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This ended up triggering these warnings when building on Ubuntu 12.04.5:
util/scripting-engines/trace-event-perl.c: In function 'perl_process_callchain':
util/scripting-engines/trace-event-perl.c:293:4: error: value computed is not used [-Werror=unused-value]
util/scripting-engines/trace-event-perl.c:294:4: error: value computed is not used [-Werror=unused-value]
util/scripting-engines/trace-event-perl.c:295:4: error: value computed is not used [-Werror=unused-value]
util/scripting-engines/trace-event-perl.c:297:4: error: value computed is not used [-Werror=unused-value]
util/scripting-engines/trace-event-perl.c:309:4: error: value computed is not used [-Werror=unused-value]
cc1: all warnings being treated as errors
mv: cannot stat `/tmp/build/perf/util/scripting-engines/.trace-event-perl.o.tmp': No such file or directory
make[4]: *** [/tmp/build/perf/util/scripting-engines/trace-event-perl.o] Error 1
Fix it by doing error checking when building the perl data structures
related to callchains.
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Dima Kogan <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Fixes: f7380c12ec6c ("perf script perl: Perl scripts now get a backtrace, like the python ones")
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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If not, tell the user that:
config/Makefile:273: Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157
And return -ENOTSUPP in die_get_var_range(), failing features that
need it, like the one pointed out above.
This fixes the build on older systems, such as Ubuntu 12.04.5.
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Vinson Lee <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Fix build error on Ubuntu 12.04.5 with GCC 4.6.3.
CC util/config.o
util/config.c: In function ‘perf_buildid_config’:
util/config.c:384:15: error: declaration of ‘dirname’ shadows a global declaration [-Werror=shadow]
Signed-off-by: Vinson Lee <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Taeung Song <[email protected]>
Cc: Wang Nan <[email protected]>
Fixes: 9cb5987c8227 ("perf config: Rework buildid_dir_command_config to perf_buildid_config")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Misc kernel side fixes:
- fix event leak
- fix AMD PMU driver bug
- fix core event handling bug
- fix build bug on certain randconfigs
Plus misc tooling fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/amd/ibs: Fix pmu::stop() nesting
perf/core: Don't leak event in the syscall error path
perf/core: Fix time tracking bug with multiplexing
perf jit: genelf makes assumptions about endian
perf hists: Fix determination of a callchain node's childlessness
perf tools: Add missing initialization of perf_sample.cpumode in synthesized samples
perf tools: Fix build break on powerpc
perf/x86: Move events_sysfs_show() outside CPU_SUP_INTEL
perf bench: Fix detached tarball building due to missing 'perf bench memcpy' headers
perf tests: Fix tarpkg build test error output redirection
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Before this patch we can see very large time in the events before the
'bpf-output' event. For example:
# perf trace -vv -T --ev sched:sched_switch \
--ev bpf-output/no-inherit,name=evt/ \
--ev ./test_bpf_trace.c/map:channel.event=evt/ \
usleep 10
...
18446744073709.551 (18446564645918.480 ms): usleep/4157 nanosleep(rqtp: 0x7ffd3f0dc4e0) ...
18446744073709.551 ( ): evt:Raise a BPF event!..)
179427791.076 ( ): perf_bpf_probe:func_begin:(ffffffff810eb9a0))
179427791.081 ( ): sched:sched_switch:usleep:4157 [120] S ==> swapper/2:0 [120])
...
We can also see the differences between bpf-output events and
breakpoint events:
For bpf output event:
sample_type IP|TID|RAW|IDENTIFIER
For tracepoint events:
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
This patch fix this differences by adding more sample type for
bpf-output events.
After this patch:
# perf trace -vv -T --ev sched:sched_switch \
--ev bpf-output/no-inherit,name=evt/ \
--ev ./test_bpf_trace.c/map:channel.event=evt/ \
usleep 10
...
179877370.878 ( 0.003 ms): usleep/5336 nanosleep(rqtp: 0x7ffff866c450) ...
179877370.878 ( ): evt:Raise a BPF event!..)
179877370.878 ( ): perf_bpf_probe:func_begin:(ffffffff810eb9a0))
179877370.882 ( ): sched:sched_switch:usleep:5336 [120] S ==> swapper/4:0 [120])
179877370.945 ( ): evt:Raise a BPF event!..)
...
# ./perf trace -vv -T --ev sched:sched_switch \
--ev bpf-output/no-inherit,name=evt/ \
--ev ./test_bpf_trace.c/map:channel.event=evt/ \
usleep 10 2>&1 | grep sample_type
sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW
sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW
sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW
sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW
sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW
sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW
The 'IDENTIFIER' info is not required because all events have the same
sample_type.
Committer notes:
Further testing, on top of the changes making 'perf trace' avoid samples
from events without PERF_SAMPLE_TIME:
Before:
# trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10
<SNIP>
0.560 ( 0.001 ms): brk( ) = 0x55e5a1df8000
18446640227439.430 (18446640227438.859 ms): nanosleep(rqtp: 0x7ffc96643370) ...
18446640227439.430 ( ): evt:Raise a BPF event!..)
0.576 ( ): perf_bpf_probe:func_begin:(ffffffff81112460))
18446640227439.430 ( ): evt:Raise a BPF event!..)
0.645 ( ): perf_bpf_probe:func_end:(ffffffff81112460 <- ffffffff81003d92))
0.646 ( 0.076 ms): ... [continued]: nanosleep()) = 0
#
After:
# trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10
<SNIP>
0.292 ( 0.001 ms): brk( ) = 0x55c7cd6e1000
0.302 ( 0.004 ms): nanosleep(rqtp: 0x7ffedd8bc0f0) ...
0.302 ( ): evt:Raise a BPF event!..)
0.303 ( ): perf_bpf_probe:func_begin:(ffffffff81112460))
0.397 ( ): evt:Raise a BPF event!..)
0.397 ( ): perf_bpf_probe:func_end:(ffffffff81112460 <- ffffffff81003d92))
0.398 ( 0.100 ms): ... [continued]: nanosleep()) = 0
Signed-off-by: Wang Nan <[email protected]>
Reported-and-Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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This was causing bogus values to be shown at the timestamp column:
Before:
# trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10
94631143.385 ( 0.001 ms): brk( ) = 0x555555757000
94631143.398 ( 0.003 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: -1) = 0x7ffff7ff6000
94631143.406 ( 0.004 ms): access(filename: 0xf7df9e10, mode: R ) = -1 ENOENT No such file or directory
94631143.412 ( 0.004 ms): open(filename: 0xf7df8761, flags: CLOEXEC) = 3
94631143.415 ( 0.002 ms): fstat(fd: 3, statbuf: 0x7fffffffd6b0 ) = 0
94631143.419 ( 0.003 ms): mmap(len: 106798, prot: READ, flags: PRIVATE, fd: 3) = 0x7ffff7fdb000
94631143.420 ( 0.001 ms): close(fd: 3 ) = 0
94631143.432 ( 0.004 ms): open(filename: 0xf7ff6640, flags: CLOEXEC) = 3
<SNIP>
After:
# trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10
0.022 ( 0.001 ms): brk( ) = 0x55d7668a6000
0.037 ( 0.003 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: -1) = 0x7f8fbeb97000
0.123 ( 0.083 ms): access(filename: 0xbe995e10, mode: R ) = -1 ENOENT No such file or directory
0.130 ( 0.004 ms): open(filename: 0xbe994761, flags: CLOEXEC) = 3
0.133 ( 0.002 ms): fstat(fd: 3, statbuf: 0x7fff6487a890 ) = 0
0.138 ( 0.003 ms): mmap(len: 106798, prot: READ, flags: PRIVATE, fd: 3) = 0x7f8fbeb7c000
0.140 ( 0.001 ms): close(fd: 3 ) = 0
0.151 ( 0.004 ms): open(filename: 0xbeb97640, flags: CLOEXEC) = 3
<SNIP>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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That is used in both live runs, i.e.:
# trace ls
As when processing events recorded in a perf.data file:
# trace -i perf.data
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Currently the max value of format is calculated by the bits number. It
relies on the continuity of the format.
However, uncore event format is not continuous. E.g. uncore qpi event
format can be 0-7,21.
If bit 21 is set, there is parsing issues as below.
$ perf stat -a -e uncore_qpi_0/event=0x200002,umask=0x8/
event syntax error: '..pi_0/event=0x200002,umask=0x8/'
\___ value too big for format, maximum is 511
This patch return the real max value by setting all possible bits to 1.
Signed-off-by: Kan Liang <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Jiri Olsa <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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For Intel PT / BTS, define the environment variable that selects TSC
timestamps in the jitdump file.
Signed-off-by: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Intel PT uses TSC as a timestamp, so add support for using TSC instead
of the monotonic clock. Use of TSC is selected by an environment
variable "JITDUMP_USE_ARCH_TIMESTAMP" and flagged in the jitdump file
with flag JITDUMP_FLAGS_ARCH_TIMESTAMP.
Signed-off-by: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Added the fixup from He Kuang to make it build on other arches, ]
[ such as aarch64, to avoid inserting this bisectiong breakage upstream ]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Intel PT uses the time members from the perf_event_mmap_page to convert
between TSC and perf time.
Due to a lack of foresight when Intel PT was implemented, those time
members were recorded in the (implementation dependent) AUXTRACE_INFO
event, the structure of which is generally inaccessible outside of the
Intel PT decoder. However now the conversion between TSC and perf time
is needed when processing a jitdump file when Intel PT has been used for
tracing.
So add a user event to record the time members. 'perf record' will
synthesize the event if the information is available. And session
processing will put a copy of the event on the session so that tools
like 'perf inject' can easily access it.
Signed-off-by: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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# trace -e getrandom
35622.560 ( 0.023 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
35622.585 ( 0.006 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
35622.594 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
35627.395 ( 0.010 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK ) = 16
35630.940 ( 0.013 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK ) = 16
35718.613 ( 0.015 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
35718.629 ( 0.005 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
35718.637 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
35719.355 ( 0.010 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK ) = 16
35721.042 ( 0.030 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK ) = 16
41090.830 ( 0.012 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
41090.845 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
41090.851 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
41091.750 ( 0.010 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK ) = 16
41091.823 ( 0.006 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK ) = 16
41122.078 ( 0.053 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
41122.129 ( 0.009 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
41122.139 ( 0.004 ms): systemd-udevd/631 getrandom(buf: 0x55621e3c18f0, count: 16, flags: NONBLOCK) = 16
41124.492 ( 0.007 ms): libvirtd/1353 getrandom(buf: 0x7f7a1bfa35c0, count: 16, flags: NONBLOCK ) = 16
41124.470 ( 0.013 ms): fwupd/16120 getrandom(buf: 0x7f63243aa5c0, count: 16, flags: NONBLOCK ) = 16
41590.832 ( 0.014 ms): chrome/5957 getrandom(buf: 0x7fabac7b15b0, count: 16, flags: NONBLOCK ) = 16
41590.884 ( 0.004 ms): chrome/5957 getrandom(buf: 0x7fabac7b15c0, count: 16, flags: NONBLOCK ) = 16
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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E.g:
# trace -e seccomp
200.061 (0.009 ms): :2441/2441 seccomp(op: FILTER, flags: TSYNC ) = -1 EFAULT Bad address
200.910 (0.121 ms): :2441/2441 seccomp(op: FILTER, flags: TSYNC, uargs: 0x7fff57479fe0) = 0
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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We catch this record to provide a visual indication that events are
getting lost, then call the default method to allow extra logging shared
with the other tools to take place.
This extra logging was done twice because we were continuing to the
"default" clause where machine__process_event() will end up calling
machine__process_lost_event() again, fix it.
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull perf/core improvements and fixes:
User visible changes:
- Add support for skipping itrace instructions, useful to fast forward
processor trace (Intel PT, BTS) to right after initialization code at the start
of a workload (Andi Kleen)
- Add support for backtraces in perl 'perf script's (Dima Kogan)
- Add -U/-K (--all-user/--all-kernel) options to 'perf mem' (Jiri Olsa)
- Make -f/--force option documentation consistent across tools (Jiri Olsa)
Infrastructure changes:
- Add 'perf test' to check for event times (Jiri Olsa)
- 'perf config' cleanups (Taeung Song)
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Commit 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
incorrectly assumed that PowerPC is big endian only.
Simplify things by consolidating the define of GEN_ELF_ENDIAN and checking
for __BYTE_ORDER == __BIG_ENDIAN.
The PowerPC checks were also incorrect, they do not match what gcc
emits. We should first look for __powerpc64__, then __powerpc__.
Signed-off-by: Anton Blanchard <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Cc: Carl Love <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Cc: [email protected]
Fixes: 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
Link: http://lkml.kernel.org/r/20160329175944.33a211cc@kryten
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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The 4b3a3212233a ("perf hists browser: Support flat callchains") commit
over-aggressively tried to optimize callchain_node__init_have_children().
That lead to --tui mode not allowing to expand call chain elements if a
call chain element had only one parent. That's why --inverted callgraphs
looked halfway sane, but plain ones didn't.
Revert that individual optimization, it wasn't really related to the
rest of the commit.
Signed-off-by: Andres Freund <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Fixes: 4b3a3212233a ("perf hists browser: Support flat callchains")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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When using 'perf script' to look at PT traces it is often useful to
ignore the initialization code at the beginning.
On larger traces which may have many millions of instructions in
initialization code doing that in a pipeline can be very slow, with perf
script spending a lot of CPU time calling printf and writing data.
This patch adds an extension to the --itrace argument that skips 'n'
events (instructions, branches or transactions) at the beginning. This
is much more efficient.
v2:
Add support for BTS (Adrian Hunter)
Document in itrace.txt
Fix branch check
Check transactions and instructions too
Committer note:
To test intel_pt one needs to make sure VT-x isn't active, i.e.
stopping KVM guests on the test machine, as described by Andi Kleen
at http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andi Kleen <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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We have some infrastructure to use perl or python to analyze logs
generated by perf. Prior to this patch, only the python tools had
access to backtrace information. This patch makes this information
available to perl scripts as well. Example:
Let's look at malloc() calls made by the seq utility. First we
create a probe point:
$ perf probe -x /lib/x86_64-linux-gnu/libc.so.6 malloc
Added new events:
...
Now we run seq, while monitoring malloc() calls with perf
$ perf record --call-graph=dwarf -e probe_libc:malloc seq 5
1
2
3
4
5
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.064 MB perf.data (6 samples) ]
We can use perf to look at its log to see the malloc calls and the backtrace
$ perf script
seq 14195 [000] 1927993.748254: probe_libc:malloc: (7f9ff8edd320) bytes=0x22
7f9ff8edd320 malloc (/lib/x86_64-linux-gnu/libc-2.22.so)
7f9ff8e8eab0 set_binding_values.part.0 (/lib/x86_64-linux-gnu/libc-2.22.so)
7f9ff8e8eda1 __bindtextdomain (/lib/x86_64-linux-gnu/libc-2.22.so)
401b22 main (/usr/bin/seq)
7f9ff8e82610 __libc_start_main (/lib/x86_64-linux-gnu/libc-2.22.so)
402799 _start (/usr/bin/seq)
...
We can also use the scripting facilities. We create a skeleton perl
script that simply prints out the events
$ perf script -g perl
generated Perl script: perf-script.pl
We can then use this script to see the malloc() calls with a
backtrace. Prior to this patch, the backtrace was not available to
the perl scripts.
$ perf script -s perf-script.pl
probe_libc::malloc 0 1927993.748254260 14195 seq __probe_ip=140325052863264, bytes=34
[7f9ff8edd320] malloc
[7f9ff8e8eab0] set_binding_values.part.0
[7f9ff8e8eda1] __bindtextdomain
[401b22] main
[7f9ff8e82610] __libc_start_main
[402799] _start
...
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dima Kogan <[email protected]>
|
|
Change the variable name 'v' to 'home' to make it more readable.
Signed-off-by: Taeung Song <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
To avoid repeated calling perf_config() remove
buildid_dir_command_config() and add new perf_buildid_config into
perf_default_config.
Because perf_config() is already called with perf_default_config at
main().
Signed-off-by: Taeung Song <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Signed-off-by: Taeung Song <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
This test creates software event 'cpu-clock' attaches it in several ways
and checks that enabled and running times match.
Committer notes:
Testing it:
[acme@jouet linux]$ perf test -v times
44: Test events times :
--- start ---
test child forked, pid 27170
attaching to spawned child, enable on exec
OK : ena 307328, run 307328
attaching to current thread as enabled
OK : ena 7826, run 7826
attaching to current thread as disabled
OK : ena 738, run 738
attaching to CPU 0 as enabled
SKIP : not enough rights
attaching to CPU 0 as enabled
SKIP : not enough rights
test child finished with -2
---- end ----
Test events times: Skip
[acme@jouet linux]$
[root@jouet ~]# perf test times
44: Test events times : Ok
[root@jouet ~]# perf test -v times
44: Test events times :
--- start ---
test child forked, pid 27306
attaching to spawned child, enable on exec
OK : ena 479290, run 479290
attaching to current thread as enabled
OK : ena 11356, run 11356
attaching to current thread as disabled
OK : ena 987, run 987
attaching to CPU 0 as enabled
OK : ena 3717, run 3717
attaching to CPU 0 as enabled
OK : ena 2323, run 2323
test child finished with 0
---- end ----
Test events times: Ok
[root@jouet ~]#
Signed-off-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Signed-off-by: Jiri Olsa <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
No need to export hists__collapse_insert_entry function.
Signed-off-by: Jiri Olsa <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Add -U/-K (--all-user/--all-kernel) options to use the perf record
--all-user/--all-kernel options.
Signed-off-by: Jiri Olsa <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
samples
In 473398a21d28 ("perf tools: Add cpumode to struct perf_sample"), I
missed some places where perf_sample fields are directly initialized in
addition to what is done in perf_evsel__parse_sample(), namely when
synthesizing PERF_RECORD_{MMAP*,COMM,FORK,EXIT} for pre-existing threads
and also in intel_pt and intel_bts when synthesizing events from
processor trace, the jitdump code also was affected, fix it.
The problem was noticed with running:
# perf record -e intel_pt//u true
# perf script
Where the samples wouldn't get resolved because perf_sample.cpumode
would be left as zero, i.e. PERF_RECORD_MISC_CPUMODE_UNKNOWN, not
resolving as kernel, hypervisor or user cpu modes.
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 473398a21d28 ("perf tools: Add cpumode to struct perf_sample")
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Commit 531d2410635c ("perf tools: Do not include stringify.h from the
kernel sources") seems to have accidentially removed the inclusion of
"util/header.h" from "arch/powerpc/util/header.c".
"util/header.h" provides the prototype for get_cpuid() and is needed to
build perf on Powerpc:
arch/powerpc/util/header.c:17:1: error: no previous prototype for 'get_cpuid' [-Werror=missing-prototypes]
Reported-by: Michael Ellerman <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Fixes: 531d2410635c ("perf tools: Do not include stringify.h from the kernel sources")
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
[ Included "util.h" too, to get the scnprintf() prototype ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"This tree contains various perf fixes on the kernel side, plus three
hw/event-enablement late additions:
- Intel Memory Bandwidth Monitoring events and handling
- the AMD Accumulated Power Mechanism reporting facility
- more IOMMU events
... and a final round of perf tooling updates/fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
perf llvm: Use strerror_r instead of the thread unsafe strerror one
perf llvm: Use realpath to canonicalize paths
perf tools: Unexport some methods unused outside strbuf.c
perf probe: No need to use formatting strbuf method
perf help: Use asprintf instead of adhoc equivalents
perf tools: Remove unused perf_pathdup, xstrdup functions
perf tools: Do not include stringify.h from the kernel sources
tools include: Copy linux/stringify.h from the kernel
tools lib traceevent: Remove redundant CPU output
perf tools: Remove needless 'extern' from function prototypes
perf tools: Simplify die() mechanism
perf tools: Remove unused DIE_IF macro
perf script: Remove lots of unused arguments
perf thread: Rename perf_event__preprocess_sample_addr to thread__resolve
perf machine: Rename perf_event__preprocess_sample to machine__resolve
perf tools: Add cpumode to struct perf_sample
perf tests: Forward the perf_sample in the dwarf unwind test
perf tools: Remove misplaced __maybe_unused
perf list: Fix documentation of :ppp
perf bench numa: Fix assertion for nodes bitfield
...
|
|
headers
A change on kernel files included by the 'perf bench memcpy' code grew some new
include deps, breaking the detached tarball build:
$ make -C tools/perf build-test
make: Entering directory '/home/acme/git/linux/tools/perf'
- tarpkg: ./tests/perf-targz-src-pkg .
tests/make:302: recipe for target 'tarpkg' failed
make[1]: *** [tarpkg] Error 2
Makefile:102: recipe for target 'build-test' failed
make: *** [build-test] Error 2
make: Leaving directory '/home/acme/git/linux/tools/perf'
$ cat tools/perf/tarpkg
./tests/perf-targz-src-pkg .
PERF_VERSION = 4.5.g05f5ec
PERF_VERSION = 4.5.g05f5ec
In file included from bench/mem-memcpy-x86-64-asm.S:9:0:
bench/../../../arch/x86/lib/memcpy_64.S:5:29: fatal error: asm/cpufeatures.h: No such file or directory
compilation terminated.
mv: cannot stat ‘bench/.mem-memcpy-x86-64-asm.o.tmp’: No such file or directory
make[5]: *** [bench/mem-memcpy-x86-64-asm.o] Error 1
make[5]: *** Waiting for unfinished jobs....
make[4]: *** [bench] Error 2
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [perf-in.o] Error 2
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [all] Error 2
$
Add arch/*/include/asm/*features.h to tools/perf/MANIFEST so that we can
continue to use detached tarballs to build perf.
Now it builds ok, doing it manually:
$ make help | grep perf
perf-tar-src-pkg - Build perf-4.5.0.tar source tarball
perf-targz-src-pkg - Build perf-4.5.0.tar.gz source tarball
perf-tarbz2-src-pkg - Build perf-4.5.0.tar.bz2 source tarball
perf-tarxz-src-pkg - Build perf-4.5.0.tar.xz source tarball
$ ls -la perf-4.5.0.tar
ls: cannot access perf-4.5.0.tar: No such file or directory
$ make perf-tar-src-pkg
TAR
PERF_VERSION = 4.5.g32c25b
$ ls -la perf-4.5.0.tar
-rw-rw-r--. 1 acme acme 6318080 Mar 24 11:52 perf-4.5.0.tar
$ mv perf-4.5.0.tar /tmp
$ cd /tmp
$ tar xf perf-4.5.0.tar
$ cd perf-4.5.0/tools/perf
$ make > /dev/null
PERF_VERSION = 4.5.g32c25b
$ ls -la perf
-rwxrwxr-x. 1 acme acme 14046416 Mar 24 11:53 perf
$ ./perf --version
perf version 4.5.g32c25b
$ perf bench
Usage:
perf bench [<common options>] <collection> <benchmark> [<options>]
# List of all available benchmark collections:
sched: Scheduler and IPC benchmarks
mem: Memory access benchmarks
numa: NUMA scheduling and MM benchmarks
futex: Futex stressing benchmarks
all: All benchmarks
$ perf bench mem
# List of available benchmarks for collection 'mem':
memcpy: Benchmark for memcpy() functions
memset: Benchmark for memset() functions
all: Run all memory access benchmarks
$ perf bench mem memcpy
# Running 'mem/memcpy' benchmark:
# function 'default' (Default memcpy() provided by glibc)
# Copying 1MB bytes ...
15.024038 GB/sec
# function 'x86-64-unrolled' (unrolled memcpy() in arch/x86/lib/memcpy_64.S)
# Copying 1MB bytes ...
17.438616 GB/sec
# function 'x86-64-movsq' (movsq-based memcpy() in arch/x86/lib/memcpy_64.S)
# Copying 1MB bytes ...
25.040064 GB/sec
# function 'x86-64-movsb' (movsb-based memcpy() in arch/x86/lib/memcpy_64.S)
# Copying 1MB bytes ...
25.040064 GB/sec
$
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Hitoshi Mitake <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
So we need to trow away just stdout, leaving stderr to be caught by
the build tests infrastructure, so that we can see what went wrong
when the tarpkg build test fails:
$ make -C tools/perf build-test
make: Entering directory '/home/acme/git/linux/tools/perf'
- tarpkg: ./tests/perf-targz-src-pkg .
tests/make:302: recipe for target 'tarpkg' failed
make[1]: *** [tarpkg] Error 2
Makefile:102: recipe for target 'build-test' failed
make: *** [build-test] Error 2
make: Leaving directory '/home/acme/git/linux/tools/perf'
$ cat tools/perf/tarpkg
./tests/perf-targz-src-pkg .
PERF_VERSION = 4.5.g05f5ec
PERF_VERSION = 4.5.g05f5ec
In file included from bench/mem-memcpy-x86-64-asm.S:9:0:
bench/../../../arch/x86/lib/memcpy_64.S:5:29: fatal error: asm/cpufeatures.h: No such file or directory
compilation terminated.
mv: cannot stat ‘bench/.mem-memcpy-x86-64-asm.o.tmp’: No such file or directory
make[5]: *** [bench/mem-memcpy-x86-64-asm.o] Error 1
make[5]: *** Waiting for unfinished jobs....
make[4]: *** [bench] Error 2
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [perf-in.o] Error 2
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [all] Error 2
$
So the test flow is:
1. Run: 'make -C tools/perf build-test'
2. One of its tests failed, in this case, the 'tarpkg' one
3. Look at what went wrong, by looking at the output of that test, in
tools/perf/tarpkg
Admittedly, this should be shortcircuited to showing what went wrong directly
from the 'make build-test' step, but lets first fix this tarpkg one and the
problem it spotted, which should be fixed by adding some extra file to the
tools/perf/MANIFEST so that detached tarballs continue being self contained and
build successfully.
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
To kill the last user of make_nonrelative_path(), that gets ditched,
one more panicking function killed.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
We have addch() for chars, add() for fixed size data, and addstr() for
variable length strings, use them.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
That doesn't chekcs malloc return and that, when using strbuf, if it
can't grow, just explodes away via die().
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Use instead the copy just made to tools/include/linux/.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
This should die altogether, but for now lets remove a bit of this stuff,
as it is not used at all.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Since none of the perf_event fields are used anymore, just the
perf_sample ones, and since this resolves to (map, symbol) from data
structures within struct thread, rename it to thread__resolve and make
the argument ordering similar to the one in machine__resolve().
Cc: Adrian Hunter <[email protected]>
Cc: Hemant Kumar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Since we only deal with fields in the passed struct perf_sample move
this method to struct machine, that is where the perf_sample fields
will be resolved to a struct addr_location, i.e. thread, map, symbol,
etc.
Cc: Adrian Hunter <[email protected]>
Cc: Hemant Kumar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
To avoid parsing event->header.misc in many locations.
This will also allow setting perf.sample.{ip,cpumode} in a single place,
from tracepoint fields, as needed by 'perf kvm' with PPC guests, where
the guest hardware counters is not available at the host.
Cc: Adrian Hunter <[email protected]>
Cc: Hemant Kumar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
It _will_ be used, no sense in receiving it and nor fowarding it along.
Cc: Adrian Hunter <[email protected]>
Cc: Hemant Kumar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
All over the tree.
Cc: David Ahern <[email protected]>
cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Correctly document what is implemented for :ppp on Intel CPUs in recent
kernels.
Signed-off-by: Andi Kleen <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Comparing bits and bytes in numa benchmark assertion
I hit the issue on two socket Power8 machine presenting its numa nodes
as 0,1,16,17 (according to numactl). Therefore I got error (and hang of
parent process):
perf: bench/numa.c:296: bind_to_memnode: Assertion `!(g->p.nr_nodes > (int)sizeof(nodemask))' failed.
This is obviously false positive. We can fit all the 18 nodes into
bitfield of 8 bytes (long on 64b architecture).
Signed-off-by: Jakub Jelen <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jakub Jelen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull 'objtool' stack frame validation from Ingo Molnar:
"This tree adds a new kernel build-time object file validation feature
(ONFIG_STACK_VALIDATION=y): kernel stack frame correctness validation.
It was written by and is maintained by Josh Poimboeuf.
The motivation: there's a category of hard to find kernel bugs, most
of them in assembly code (but also occasionally in C code), that
degrades the quality of kernel stack dumps/backtraces. These bugs are
hard to detect at the source code level. Such bugs result in
incorrect/incomplete backtraces most of time - but can also in some
rare cases result in crashes or other undefined behavior.
The build time correctness checking is done via the new 'objtool'
user-space utility that was written for this purpose and which is
hosted in the kernel repository in tools/objtool/. The tool's (very
simple) UI and source code design is shaped after Git and perf and
shares quite a bit of infrastructure with tools/perf (which tooling
infrastructure sharing effort got merged via perf and is already
upstream). Objtool follows the well-known kernel coding style.
Objtool does not try to check .c or .S files, it instead analyzes the
resulting .o generated machine code from first principles: it decodes
the instruction stream and interprets it. (Right now objtool supports
the x86-64 architecture.)
From tools/objtool/Documentation/stack-validation.txt:
"The kernel CONFIG_STACK_VALIDATION option enables a host tool named
objtool which runs at compile time. It has a "check" subcommand
which analyzes every .o file and ensures the validity of its stack
metadata. It enforces a set of rules on asm code and C inline
assembly code so that stack traces can be reliable.
Currently it only checks frame pointer usage, but there are plans to
add CFI validation for C files and CFI generation for asm files.
For each function, it recursively follows all possible code paths
and validates the correct frame pointer state at each instruction.
It also follows code paths involving special sections, like
.altinstructions, __jump_table, and __ex_table, which can add
alternative execution paths to a given instruction (or set of
instructions). Similarly, it knows how to follow switch statements,
for which gcc sometimes uses jump tables."
When this new kernel option is enabled (it's disabled by default), the
tool, if it finds any suspicious assembly code pattern, outputs
warnings in compiler warning format:
warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup
warning: objtool:__schedule()+0x3c0: duplicate frame pointer save
warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer
... so that scripts that pick up compiler warnings will notice them.
All known warnings triggered by the tool are fixed by the tree, most
of the commits in fact prepare the kernel to be warning-free. Most of
them are bugfixes or cleanups that stand on their own, but there are
also some annotations of 'special' stack frames for justified cases
such entries to JIT-ed code (BPF) or really special boot time code.
There are two other long-term motivations behind this tool as well:
- To improve the quality and reliability of kernel stack frames, so
that they can be used for optimized live patching.
- To create independent infrastructure to check the correctness of
CFI stack frames at build time. CFI debuginfo is notoriously
unreliable and we cannot use it in the kernel as-is without extra
checking done both on the kernel side and on the build side.
The quality of kernel stack frames matters to debuggability as well,
so IMO we can merge this without having to consider the live patching
or CFI debuginfo angle"
* 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
objtool: Only print one warning per function
objtool: Add several performance improvements
tools: Copy hashtable.h into tools directory
objtool: Fix false positive warnings for functions with multiple switch statements
objtool: Rename some variables and functions
objtool: Remove superflous INIT_LIST_HEAD
objtool: Add helper macros for traversing instructions
objtool: Fix false positive warnings related to sibling calls
objtool: Compile with debugging symbols
objtool: Detect infinite recursion
objtool: Prevent infinite recursion in noreturn detection
objtool: Detect and warn if libelf is missing and don't break the build
tools: Support relative directory path for 'O='
objtool: Support CROSS_COMPILE
x86/asm/decoder: Use explicitly signed chars
objtool: Enable stack metadata validation on 64-bit x86
objtool: Add CONFIG_STACK_VALIDATION option
objtool: Add tool to perform compile-time stack metadata validation
x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard
sched: Always inline context_switch()
...
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