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The validation checks that the values that were just assigned, got
assigned i.e. the error can't ever happen. Subsequent patches will call
this code in places where errors are not being returned. Changing those
code paths to return this non-existent error is counter-productive, so
just remove it.
That in turn results in perf_evlist__set_maps not needing to return an
error, but callers aren't checking it either, so remove that too.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/1441699142-18905-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
'perf top' segfaults with following operation:
# perf top -e page-faults -p 11400 # 11400 never generates page-fault
Then on the resulting empty interface, press right key:
# ./perf top -e page-faults -p 11400
perf: Segmentation fault
-------- backtrace --------
./perf[0x535428]
/lib64/libc.so.6(+0x3545f)[0x7f0dd360745f]
./perf[0x531d46]
./perf(perf_evlist__tui_browse_hists+0x96)[0x5340d6]
./perf[0x44ba2f]
/lib64/libpthread.so.0(+0x81d0)[0x7f0dd49dc1d0]
/lib64/libc.so.6(clone+0x6c)[0x7f0dd36b90dc]
The bug resides in perf_evsel__hists_browse() that, in the above
circumstance browser->selection can be NULL, but code after
skip_annotation doesn't consider it.
This patch fix it by checking browser->selection before fetching
browser->selection->map.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1442226235-117265-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In a couple of cases the 'comm' member of 'union event' has been used
instead of the correct member ('fork') when processing exit events.
In the cases where it has been used incorrectly, only the 'pid' and
'tid' are affected. The 'pid' value would be correct anyway because it
is in the same position in 'comm' and 'fork' events, but the 'tid' would
have been incorrectly assigned from 'ppid'.
However, for exit events, the kernel puts the current task in the 'ppid'
and 'ttid' which is the same as the exiting task. That is 'ppid' ==
'pid' and if the task is not multi-threaded, 'pid' == 'tid' i.e. the
data goes wrong only when tracing multi-threaded programs.
It is hard to find an example of how this would produce an error in
practice. There are 3 occurences of the fix:
1. perf script is only affected if !sample_id_all which only happens on
old kernels.
2. intel_pt is only affected when decoding without timestamps
and would probably still decode correctly - the exit event is
only used to flush out data which anyway gets flushed at the
end of the session
3. intel_bts also uses the exit event to flush data which
would probably not cause errors as it would get flushed at
the end of the session instead
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1439888825-27708-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I hit following building error randomly:
...
/bin/sh: /path/to/kernel/buildperf/util/intel-pt-decoder/inat-tables.c: No such file or directory
...
LINK /path/to/kernel/buildperf/plugin_mac80211.so
LINK /path/to/kernel/buildperf/plugin_kmem.so
LINK /path/to/kernel/buildperf/plugin_xen.so
LINK /path/to/kernel/buildperf/plugin_hrtimer.so
In file included from util/intel-pt-decoder/intel-pt-insn-decoder.c:25:0:
util/intel-pt-decoder/inat.c:24:25: fatal error: inat-tables.c: No such file or directory
#include "inat-tables.c"
^
compilation terminated.
make[4]: *** [/path/to/kernel/buildperf/util/intel-pt-decoder/intel-pt-insn-decoder.o] Error 1
make[4]: *** Waiting for unfinished jobs....
LINK /path/to/kernel/buildperf/plugin_function.so
This is caused by tools/perf/util/intel-pt-decoder/Build that, it tries
to generate $(OUTPUT)util/intel-pt-decoder/inat-tables.c atomatically
but forget to ensure the existance of $(OUTPUT)util/intel-pt-decoder
directory.
This patch fixes it by adding $(call rule_mkdir) like other similar rules.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1441087005-107540-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch modifies the -I/--int-regs option to enablepassing the name
of the registers to sample on interrupt. Registers can be specified by
their symbolic names. For instance on x86, --intr-regs=ax,si.
The motivation is to reduce the size of the perf.data file and the
overhead of sampling by only collecting the registers useful to a
specific analysis. For instance, for value profiling, sampling only the
registers used to passed arguements to functions.
With no parameter, the --intr-regs still records all possible registers
based on the architecture.
To name registers, it is necessary to use the long form of the option,
i.e., --intr-regs:
$ perf record --intr-regs=si,di,r8,r9 .....
To record any possible registers:
$ perf record -I .....
$ perf report --intr-regs ...
To display the register, one can use perf report -D
To list the available registers:
$ perf record --intr-regs=\?
available registers: AX BX CX DX SI DI BP SP IP FLAGS CS SS R8 R9 R10 R11 R12 R13 R14 R15
Signed-off-by: Stephane Eranian <eranian@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1441039273-16260-4-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It is theoretically possible to process perf.data files created on x86
and that contain Intel PT or Intel BTS data, on any other architecture,
which is why it is possible for there to be build errors on powerpc
caused by pt/bts.
The errors were:
util/intel-pt-decoder/intel-pt-insn-decoder.c: In function ‘intel_pt_insn_decoder’:
util/intel-pt-decoder/intel-pt-insn-decoder.c:138:3: error: switch missing default case [-Werror=switch-default]
switch (insn->immediate.nbytes) {
^
cc1: all warnings being treated as errors
linux-acme.git/tools/perf/perf-obj/libperf.a(libperf-in.o): In function `intel_pt_synth_branch_sample':
sources/linux-acme.git/tools/perf/util/intel-pt.c:871: undefined reference to `tsc_to_perf_time'
linux-acme.git/tools/perf/perf-obj/libperf.a(libperf-in.o): In function `intel_pt_sample':
sources/linux-acme.git/tools/perf/util/intel-pt.c:915: undefined reference to `tsc_to_perf_time'
sources/linux-acme.git/tools/perf/util/intel-pt.c:962: undefined reference to `tsc_to_perf_time'
linux-acme.git/tools/perf/perf-obj/libperf.a(libperf-in.o): In function `intel_pt_process_event':
sources/linux-acme.git/tools/perf/util/intel-pt.c:1454: undefined reference to `perf_time_to_tsc'
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1441046384-28663-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/core improvement and fixes from Arnaldo Carvalho de Melo:
User visible changes:
- Add new compaction-times python script. (Tony Jones)
- Make the --[no-]-demangle/--[no-]-demangle-kernel command line
options available in 'perf script' too. (Mark Drayton)
- Allow for negative numbers in libtraceevent's print format,
fixing up misformatting in some tracepoints. (Steven Rostedt)
Infrastructure changes:
- perf_env/perf_evlist changes to allow accessing the data
structure with the environment where some perf data was
collected in functions not necessarily related to perf.data
file processing. (Kan Liang)
- Cleanups for the tracepoint definition location paths routines. (Jiri Olsa)
- Introduce sysfs/filename__sprintf_build_id, removing code
duplication. (Masami Hiramatsu)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch creates a new script (compaction-times) to report time
spent in mm compaction. It is possible to report times in nanoseconds
(default) or microseconds (-u).
The option -p will break down results by process id, -pv will further
decompose by each compaction entry/exit.
For each compaction entry/exit what is reported is controlled by the
options:
-t report only timing
-m report migration stats
-ms report migration scanner stats
-fs report free scanner stats
The default is to report all.
Entries may be further filtered by pid, pid-range or comm (regex).
The script is useful when analysing workloads that compact memory. The
most common example will be THP allocations on systems with a lot of
uptime that has fragmented memory.
This is an example of using the script to analyse a thpscale from
mmtests which deliberately fragments memory and allocates THP in 4
separate threads
# Recording step, one of the following;
$ perf record -e 'compaction:mm_compaction_*' ./workload
# or:
$ perf script record compaction-times
# Reporting: basic
total: 2444505743ns migration: moved=357738 failed=39275
free_scanner: scanned=2705578 isolated=387875
migration_scanner: scanned=414426 isolated=397013
# Reporting: Per task stall times
$ perf script report compaction-times -- -t -p
total: 2444505743ns
6384[thpscale]: 740800017ns
6385[thpscale]: 274119512ns
6386[thpscale]: 832961337ns
6383[thpscale]: 596624877ns
# Reporting: Per-compaction attempts for task 6385
$ perf script report compaction-times -- -m -pv 6385
total: 274119512ns migration: moved=14893 failed=24285
6385[thpscale]: 274119512ns migration: moved=14893 failed=24285
6385[thpscale].1: 3033277ns migration: moved=511 failed=1
6385[thpscale].2: 9592094ns migration: moved=1524 failed=12
6385[thpscale].3: 2495587ns migration: moved=512 failed=0
6385[thpscale].4: 2561766ns migration: moved=512 failed=0
6385[thpscale].5: 2523521ns migration: moved=512 failed=0
..... output continues ...
Changes since v1:
- report stats for isolate_migratepages and isolate_freepages
(Vlastimil Babka)
- refactor code to achieve above
- add help text
- output to stdout/stderr explicitly
Signed-off-by: Tony Jones <tonyj@suse.com>
Cc: Mel Gorman <mgorman@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1439840932-8933-1-git-send-email-tonyj@suse.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
print_aggr() fails to print per-core/per-socket statistics after commit
582ec0829b ("perf stat: Fix per-socket output bug for uncore events")
if events have differnt cpus. Because in print_aggr(), aggr_get_id needs
index (not cpu id) to find core/pkg id. Also, evsel cpu maps should be
used to get aggregated id.
Here is an example:
Counting events cycles,uncore_imc_0/cas_count_read/. (Uncore event has
cpumask 0,18)
$ perf stat -e cycles,uncore_imc_0/cas_count_read/ -C0,18 --per-core sleep 2
Without this patch, it failes to get CPU 18 result.
Performance counter stats for 'CPU(s) 0,18':
S0-C0 1 7526851 cycles
S0-C0 1 1.05 MiB uncore_imc_0/cas_count_read/
S1-C0 0 <not counted> cycles
S1-C0 0 <not counted> MiB uncore_imc_0/cas_count_read/
With this patch, it can get both CPU0 and CPU18 result.
Performance counter stats for 'CPU(s) 0,18':
S0-C0 1 6327768 cycles
S0-C0 1 0.47 MiB uncore_imc_0/cas_count_read/
S1-C0 1 330228 cycles
S1-C0 1 0.29 MiB uncore_imc_0/cas_count_read/
Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Stephane Eranian <eranian@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: 582ec0829b ("perf stat: Fix per-socket output bug for uncore events")
Link: http://lkml.kernel.org/r/1435820925-51091-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It should be useful to allow 'perf probe' probe at absolute offset of a
target. For example, when (u)probing at a instruction of a shared object
in a embedded system where debuginfo is not avaliable but we know the
offset of that instruction by manually digging.
This patch enables following perf probe command syntax:
# perf probe 0xffffffff811e6615
And
# perf probe /lib/x86_64-linux-gnu/libc-2.19.so 0xeb860
In the above example, we don't need a anchor symbol, so it is possible
to compute absolute addresses using other methods and then use 'perf
probe' to create the probing points.
v1 -> v2:
Drop the leading '+' in cmdline;
Allow uprobing at offset 0x0;
Improve 'perf probe -l' result when uprobe at area without debuginfo.
v2 -> v3:
Split bugfix to a separated patch.
Test result:
# perf probe 0xffffffff8119d175 %ax
# perf probe sys_write %ax
# perf probe /lib64/libc-2.18.so 0x0 %ax
# perf probe /lib64/libc-2.18.so 0x5 %ax
# perf probe /lib64/libc-2.18.so 0xd8e40 %ax
# perf probe /lib64/libc-2.18.so __write %ax
# perf probe /lib64/libc-2.18.so 0xd8e49 %ax
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_libc/abs_0 /lib64/libc-2.18.so:0x (null) arg1=%ax
p:probe_libc/abs_5 /lib64/libc-2.18.so:0x0000000000000005 arg1=%ax
p:probe_libc/abs_d8e40 /lib64/libc-2.18.so:0x00000000000d8e40 arg1=%ax
p:probe_libc/__write /lib64/libc-2.18.so:0x00000000000d8e40 arg1=%ax
p:probe_libc/abs_d8e49 /lib64/libc-2.18.so:0x00000000000d8e49 arg1=%ax
# cat /sys/kernel/debug/tracing/kprobe_events
p:probe/abs_ffffffff8119d175 0xffffffff8119d175 arg1=%ax
p:probe/sys_write _text+1692016 arg1=%ax
# perf probe -l
Failed to find debug information for address 5
probe:abs_ffffffff8119d175 (on sys_write+5 with arg1)
probe:sys_write (on sys_write with arg1)
probe_libc:__write (on @unix/syscall-template.S:81 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_0 (on 0x0 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_5 (on 0x5 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_d8e40 (on @unix/syscall-template.S:81 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_d8e49 (on __GI___libc_write+9 in /lib64/libc-2.18.so with arg1)
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440586666-235233-7-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When manually added uprobe point with zero address, 'perf probe -l'
reports error. For example:
# echo p:probe_libc/abs_0 /path/to/lib.bin:0x0 arg1=%ax > \
/sys/kernel/debug/tracing/uprobe_events
# perf probe -l
Error: Failed to show event list.
Probing at 0x0 is possible and useful when lib.bin is not a normal
shared object but is manually mapped. However, in this case kernel
report:
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_libc/abs_0 /path/to/lib.bin:0x (null) arg1=%ax
This patch supports the above kernel output.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440586666-235233-5-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
'perf probe -l' reports error if it is unable find symbol through
address. Here is an example.
# echo 'p:probe_libc/abs_5 /lib64/libc.so.6:0x5' >
/sys/kernel/debug/tracing/uprobe_events
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_libc/abs_5 /lib64/libc.so.6:0x0000000000000005
# perf probe -l
Error: Failed to show event list
Also, this situation triggers a logical inconsistency in
convert_to_perf_probe_point() that, it returns ENOMEM but actually it
never try strdup().
This patch removes !tp->module && !is_kprobe condition, so it always
uses address to build function name if symbol not found.
Test result:
# perf probe -l
probe_libc:abs_5 (on 0x5 in /lib64/libc.so.6)
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440586666-235233-4-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
'perf probe -l' panic if there is a manually inserted probing point with
absolute address. For example:
# echo 'p:probe/abs_ffffffff811e6615 0xffffffff811e6615' > /sys/kernel/debug/tracing/kprobe_events
# perf probe -l
Segmentation fault (core dumped)
This patch fix this problem by considering the situation that
"tp->symbol == NULL" in find_perf_probe_point_from_dwarf() and
find_perf_probe_point_from_map().
After this patch:
# perf probe -l
probe:abs_ffffffff811e6615 (on SyS_write+5@fs/read_write.c)
And when debug info is missing:
# rm -rf ~/.debug
# mv /lib/modules/4.2.0-rc1+/build/vmlinux /lib/modules/4.2.0-rc1+/build/vmlinux.bak
# perf probe -l
probe:abs_ffffffff811e6615 (on sys_write+5)
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440509256-193590-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
A TRACESTOP packet is produced when an Intel PT trace enters a defined
region of the address space at which point the tracing stops.
This patch just adds decoder support.
Support for specifying TRACESTOP regions is left until later.
For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-25-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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 <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-24-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.
This patch just adds decoder support. The CPU frequency can be related
to TSC using the Maximum Non-Turbo Ratio in combination with the CBR
(core-to-bus ratio) packet. However more accuracy is achieved by simply
interpolating the number of cycles between other timing packets like MTC
or TSC. This patch takes the latter approach.
Support for a default value and validation of values is provided by a
later patch. Also documentation is updated in a separate patch.
For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-23-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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 <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-22-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
