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2023-11-30libperf: Lazily allocate/size mmap event copyIan Rogers1-1/+2
The event copy in the mmap is used to have storage to read an event. Not all users of mmaps read the events, such as perf record. The amount of buffer was also statically set to PERF_SAMPLE_MAX_SIZE rather than the amount necessary from the header's event size. Switch to a model where the event_copy is reallocated if too small to the event's size. This adds the potential for the event to move, so if a copy of the event pointer were stored it could be broken. All the current users do: while(event = perf_mmap__read_event()) { ... } and so they would be broken due to the event being overwritten if they had stored the pointer. Manual inspection and address sanitizer testing also shows the event pointer not being stored. Signed-off-by: Ian Rogers <[email protected]> Acked-by: Namhyung Kim <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Athira Jajeev <[email protected]> Cc: Changbin Du <[email protected]> Cc: Colin Ian King <[email protected]> Cc: Dmitrii Dolgov <[email protected]> Cc: German Gomez <[email protected]> Cc: Guilherme Amadio <[email protected]> Cc: Huacai Chen <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Clark <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: K Prateek Nayak <[email protected]> Cc: Kajol Jain <[email protected]> Cc: Kan Liang <[email protected]> Cc: Leo Yan <[email protected]> Cc: Li Dong <[email protected]> Cc: Liam Howlett <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Masami Hiramatsu (Google) <[email protected]> Cc: Miguel Ojeda <[email protected]> Cc: Ming Wang <[email protected]> Cc: Nick Terrell <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ravi Bangoria <[email protected]> Cc: Sandipan Das <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: Steinar H. Gunderson <[email protected]> Cc: Vincent Whitchurch <[email protected]> Cc: Wenyu Liu <[email protected]> Cc: Yang Jihong <[email protected]> Link: https://lore.kernel.org/r/[email protected] [ Replace two lines with equivalent zfree(&map->event_copy) ] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
2022-01-12perf cpumap: Give CPUs their own typeIan Rogers1-2/+3
A common problem is confusing CPU map indices with the CPU, by wrapping the CPU with a struct then this is avoided. This approach is similar to atomic_t. Committer notes: To make it build with BUILD_BPF_SKEL=1 these files needed the conversions to 'struct perf_cpu' usage: tools/perf/util/bpf_counter.c tools/perf/util/bpf_counter_cgroup.c tools/perf/util/bpf_ftrace.c Also perf_env__get_cpu() was removed back in "perf cpumap: Switch cpu_map__build_map to cpu function". Additionally these needed to be fixed for the ARM builds to complete: tools/perf/arch/arm/util/cs-etm.c tools/perf/arch/arm64/util/pmu.c Suggested-by: John Garry <[email protected]> Signed-off-by: Ian Rogers <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Clark <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kajol Jain <[email protected]> Cc: Kan Liang <[email protected]> Cc: Leo Yan <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Mathieu Poirier <[email protected]> Cc: Mike Leach <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Paul Clarke <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Riccardo Mancini <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Suzuki Poulouse <[email protected]> Cc: Vineet Singh <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
2021-04-20libperf: Add support for user space counter accessRob Herring1-0/+3
x86 and arm64 can both support direct access of event counters in userspace. The access sequence is less than trivial and currently exists in perf test code (tools/perf/arch/x86/tests/rdpmc.c) with copies in projects such as PAPI and libpfm4. In order to support userspace access, an event must be mmapped first with perf_evsel__mmap(). Then subsequent calls to perf_evsel__read() will use the fast path (assuming the arch supports it). Committer notes: Added a '__maybe_unused' attribute to the read_perf_counter() argument to fix the build on arches other than x86_64 and arm. Committer testing: Building and running the libperf tests in verbose mode (V=1) now shows those "loop = N, count = N" extra lines, testing user space counter access. # make V=1 -C tools/lib/perf tests make: Entering directory '/home/acme/git/perf/tools/lib/perf' make -f /home/acme/git/perf/tools/build/Makefile.build dir=. obj=libperf make -C /home/acme/git/perf/tools/lib/api/ O= libapi.a make -f /home/acme/git/perf/tools/build/Makefile.build dir=./fd obj=libapi make -f /home/acme/git/perf/tools/build/Makefile.build dir=./fs obj=libapi make -C tests gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -o test-cpumap-a test-cpumap.c ../libperf.a /home/acme/git/perf/tools/lib/api/libapi.a gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -o test-threadmap-a test-threadmap.c ../libperf.a /home/acme/git/perf/tools/lib/api/libapi.a gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -o test-evlist-a test-evlist.c ../libperf.a /home/acme/git/perf/tools/lib/api/libapi.a gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -o test-evsel-a test-evsel.c ../libperf.a /home/acme/git/perf/tools/lib/api/libapi.a gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -L.. -o test-cpumap-so test-cpumap.c /home/acme/git/perf/tools/lib/api/libapi.a -lperf gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -L.. -o test-threadmap-so test-threadmap.c /home/acme/git/perf/tools/lib/api/libapi.a -lperf gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -L.. -o test-evlist-so test-evlist.c /home/acme/git/perf/tools/lib/api/libapi.a -lperf gcc -I/home/acme/git/perf/tools/lib/perf/include -I/home/acme/git/perf/tools/include -I/home/acme/git/perf/tools/lib -g -Wall -L.. -o test-evsel-so test-evsel.c /home/acme/git/perf/tools/lib/api/libapi.a -lperf make -C tests run running static: - running test-cpumap.c...OK - running test-threadmap.c...OK - running test-evlist.c...OK - running test-evsel.c... loop = 65536, count = 333926 loop = 131072, count = 655781 loop = 262144, count = 1311141 loop = 524288, count = 2630126 loop = 1048576, count = 5256955 loop = 65536, count = 524594 loop = 131072, count = 1058916 loop = 262144, count = 2097458 loop = 524288, count = 4205429 loop = 1048576, count = 8406606 OK running dynamic: - running test-cpumap.c...OK - running test-threadmap.c...OK - running test-evlist.c...OK - running test-evsel.c... loop = 65536, count = 328102 loop = 131072, count = 655782 loop = 262144, count = 1317494 loop = 524288, count = 2627851 loop = 1048576, count = 5255187 loop = 65536, count = 524601 loop = 131072, count = 1048923 loop = 262144, count = 2107917 loop = 524288, count = 4194606 loop = 1048576, count = 8409322 OK make: Leaving directory '/home/acme/git/perf/tools/lib/perf' # Signed-off-by: Rob Herring <[email protected]> Acked-by: Jiri Olsa <[email protected]> Acked-by: Namhyung Kim <[email protected]> Tested-by: Arnaldo Carvalho de Melo <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Itaru Kitayama <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Will Deacon <[email protected]> Link: http://lore.kernel.org/lkml/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
2020-01-06libperf: Move to tools/lib/perfJiri Olsa1-0/+55
Move libperf from its current location under tools/perf to a separate directory under tools/lib/. Also change various paths (mainly includes) to reflect the libperf move to a separate directory and add a new directory under MANIFEST. Signed-off-by: Jiri Olsa <[email protected]> Tested-by: Arnaldo Carvalho de Melo <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Michael Petlan <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lore.kernel.org/lkml/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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