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CYC packets are a new Intel PT feature.
CYC packets provide even finer grain timestamp information than MTC and
TSC packets. A CYC packet contains the number of CPU cycles since the
last CYC packet. Unlike MTC and TSC packets, CYC packets are only sent
when another packet is also sent.
Support for this feature is indicated by:
/sys/bus/event_source/devices/intel_pt/caps/psb_cyc
which contains "1" if the feature is supported and "0" otherwise.
CYC packets can be requested using a PMU config term e.g. perf record -e
intel_pt/cyc/u sleep 1
The frequency of CYC packets can also be specified. e.g. perf record -e
intel_pt/cyc,cyc_thresh=2/u sleep 1
CYC packets are not requested by default.
Valid cyc_thresh values are given by:
/sys/bus/event_source/devices/intel_pt/caps/cycle_thresholds
which contains a hexadecimal value, the bits of which represent valid
values e.g. bit 2 set means value 2 is valid.
The value represents the minimum number of CPU cycles that must have
passed before a CYC packet can be sent. The number of CPU cycles is:
2 ^ (value - 1)
e.g. value 4 means 8 CPU cycles must pass before a CYC packet can be
sent. Note a CYC packet is still only sent when another packet is sent,
not at, e.g. every 8 CPU cycles.
If an invalid value is entered, the error message will give a list of
valid values e.g.
$ perf record -e intel_pt/cyc,cyc_thresh=15/u uname
Invalid cyc_thresh for intel_pt. Valid values are: 0-12
tools/perf/Documentation/intel-pt.txt is updated in a later patch as
there are a number of new features being added.
For more information refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <[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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MTC packets are a new Intel PT feature.
MTC packets provide finer grain timestamp information than TSC packets.
Support for this feature is indicated by:
/sys/bus/event_source/devices/intel_pt/caps/mtc
which contains "1" if the feature is supported and "0" otherwise.
MTC packets can be requested using a PMU config term e.g. perf record -e
intel_pt/mtc/u sleep 1
The frequency of MTC packets can also be specified. e.g. perf record -e
intel_pt/mtc,mtc_period=2/u sleep 1
The default value is 3 or the nearest lower value that is supported. 0
is always supported.
Valid values are given by:
/sys/bus/event_source/devices/intel_pt/caps/mtc_periods
which contains a hexadecimal value, the bits of which represent valid
values e.g. bit 2 set means value 2 is valid.
The value is converted to the MTC frequency as:
CTC-frequency / (2 ^ value)
e.g. value 3 means one eighth of CTC-frequency
Where CTC is the hardware crystal clock, the frequency of which can be
related to TSC via values provided in cpuid leaf 0x15.
If an invalid value is entered, the error message will give a list of
valid values e.g.
$ perf record -e intel_pt/mtc_period=15/u uname
Invalid mtc_period for intel_pt. Valid values are: 0,3,6,9
tools/perf/Documentation/intel-pt.txt is updated in a later patch as
there are a number of new features being added.
For more information refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <[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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Record additional information in the AUXTRACE_INFO event in preparation
for decoding MTC and CYC packets. Pass the information to the decoder.
The AUXTRACE_INFO record can be extended by using the size to indicate
the presence of new members.
The additional information includes PMU config bit positions and the TSC
to CTC (hardware crystal clock) ratio needed to decode MTC packets.
Signed-off-by: Adrian Hunter <[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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The PSB packet is a synchronization packet that provides a starting
point for decoding or recovery from errors.
This patch adds support for a new Intel PT feature that allows the
frequency of PSB packets to be specified.
Support for this feature is indicated by
/sys/bus/event_source/devices/intel_pt/caps/psb_cyc which contains "1"
if the feature is supported and "0" otherwise.
The PSB period can be specified as a PMU config term e.g. perf record -e
intel_pt/psb_period=2/u sleep 1
The default value is 3 or the nearest lower value that is supported. 0
is always supported.
Valid values are given by:
/sys/bus/event_source/devices/intel_pt/caps/psb_periods
which contains a hexadecimal value, the bits of which represent valid
values e.g. bit 2 set means value 2 is valid.
The value is converted to the approximate number of trace bytes between
PSB packets as:
2 ^ (value + 11)
e.g. value 3 means 16KiB bytes between PSBs
If an invalid value is entered, the error message will give a list of
valid values e.g.
$ perf record -e intel_pt/psb_period=15/u uname
Invalid psb_period for intel_pt. Valid values are: 0-5
tools/perf/Documentation/intel-pt.txt is updated in a later patch as
there are a number of new features being added.
For more information about PSB periods refer to the Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace from June 2015 or
later.
Signed-off-by: Adrian Hunter <[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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Add support for Intel Processor Trace.
Intel PT support fits within the new auxtrace infrastructure. Recording
is supporting by identifying the Intel PT PMU, parsing options and
setting up events.
Decoding is supported by queuing up trace data by cpu or thread and then
decoding synchronously delivering synthesized event samples into the
session processing for tools to consume.
Signed-off-by: Adrian Hunter <[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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