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| author | Adrian Hunter <adrian.hunter@intel.com> | 2021-10-27 11:03:32 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-10-27 22:20:30 +0300 |
| commit | c3afd6e50fce824f551914c690f6b905787783cf (patch) | |
| tree | 3508fe29122003b3d89f0a19ac6caea58224b5aa /tools/perf/Documentation | |
| parent | f2b91386ffe66dba0860c03c9dec1c6b45c2daba (diff) | |
| download | linux-c3afd6e50fce824f551914c690f6b905787783cf.tar.xz | |
perf dlfilter: Add dlfilter-show-cycles
Add a new dlfilter to show cycles.
Cycle counts are accumulated per CPU (or per thread if CPU is not recorded)
from IPC information, and printed together with the change since the last
print, at the start of each line. Separate counts are kept for branches,
instructions or other events.
Note also, the itrace A option can be useful to provide higher granularity
cycle information.
Example:
$ perf record -e intel_pt/cyc/u uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.044 MB perf.data ]
$ perf script --itrace=A --call-trace --dlfilter dlfilter-show-cycles.so --deltatime | head
0 perf-exec 8509 [001] 0.000000000: psb offs: 0
0 perf-exec 8509 [001] 0.000000000: cbr: 42 freq: 4219 MHz (156%)
833 833 uname 8509 [001] 0.000047689: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _start
833 uname 8509 [001] 0.000003261: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_start
2015 1182 uname 8509 [001] 0.000000282: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_start
2676 661 uname 8509 [001] 0.000002629: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_start
3612 936 uname 8509 [001] 0.000001232: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_start
4579 967 uname 8509 [001] 0.000002519: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_start
6145 1566 uname 8509 [001] 0.000001050: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_setup_hash
6239 94 uname 8509 [001] 0.000000023: (/usr/lib/x86_64-linux-gnu/ld-2.31.so ) _dl_sysdep_start
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20211027080334.365596-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation')
| -rw-r--r-- | tools/perf/Documentation/perf-intel-pt.txt | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt index 8914335db84b..c792fa7b59d3 100644 --- a/tools/perf/Documentation/perf-intel-pt.txt +++ b/tools/perf/Documentation/perf-intel-pt.txt @@ -164,7 +164,9 @@ actual number of cycles increases even though the cycles reported does not. The number of instructions is known, but if IPC is reported, cycles can be too low and so IPC is too high. Note that inaccuracy decreases as the period of sampling increases i.e. if the number of cycles is too low by a small amount, -that becomes less significant if the number of cycles is large. +that becomes less significant if the number of cycles is large. It may also be +useful to use the 'A' option in conjunction with dlfilter-show-cycles.so to +provide higher granularity cycle information. Also note that the IPC instruction count may or may not include the current instruction. If the cycle count is associated with an asynchronous branch @@ -1082,6 +1084,21 @@ The Z option is equivalent to having recorded a trace without TSC decoding a trace of a virtual machine. +dlfilter-show-cycles.so +~~~~~~~~~~~~~~~~~~~~~~~ + +Cycles can be displayed using dlfilter-show-cycles.so in which case the itrace A +option can be useful to provide higher granularity cycle information: + + perf script --itrace=A --call-trace --dlfilter dlfilter-show-cycles.so + +To see a list of dlfilters: + + perf script -v --list-dlfilters + +See also linkperf:perf-dlfilters[1] + + dump option ~~~~~~~~~~~ |