summaryrefslogtreecommitdiff
path: root/tools/perf/Documentation
diff options
context:
space:
mode:
authorAdrian Hunter <adrian.hunter@intel.com>2020-07-10 18:11:04 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-08-06 15:02:43 +0300
commit347a7389a7cc9b91f80deb8d7043e9827d08b328 (patch)
tree13bd633d1f0d0b4b5df2002df6d2e9f4f9ed2d62 /tools/perf/Documentation
parent7c1b16ba0e26e6802d80c99c92529f29bcdcea25 (diff)
downloadlinux-347a7389a7cc9b91f80deb8d7043e9827d08b328.tar.xz
perf intel-pt: Add support for decoding PSB+ only
A single q option decodes ip from only FUP/TIP packets. Make it so that repeating the q option (i.e. qq) decodes only PSB+, getting ip if there is a FUP packet within PSB+ (i.e. between PSB and PSBEND). Example: $ perf record -e intel_pt//u grep -rI pudding drivers [ perf record: Woken up 52 times to write data ] [ perf record: Captured and wrote 57.870 MB perf.data ] $ time perf script --itrace=bi | wc -l 58948289 real 1m23.863s user 1m23.251s sys 0m7.452s $ time perf script --itrace=biq | wc -l 3385694 real 0m4.453s user 0m4.455s sys 0m0.328s $ time perf script --itrace=biqq | wc -l 1883 real 0m0.047s user 0m0.043s sys 0m0.009s Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lore.kernel.org/lkml/20200710151104.15137-13-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.txt15
1 files changed, 15 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt
index f9fe4a4040ba..d5a266d7f15b 100644
--- a/tools/perf/Documentation/perf-intel-pt.txt
+++ b/tools/perf/Documentation/perf-intel-pt.txt
@@ -999,6 +999,21 @@ What *will* be decoded with the (single) q option:
Note the q option does not specify what events will be synthesized e.g. the p
option must be used also to show power events.
+Repeating the q option (double-q i.e. qq) results in even faster decoding and even
+less detail. The decoder decodes only extended PSB (PSB+) packets, getting the
+instruction pointer if there is a FUP packet within PSB+ (i.e. between PSB and
+PSBEND). Note PSB packets occur regularly in the trace based on the psb_period
+config term (refer config terms section). There will be a FUP packet if the
+PSB+ occurs while control flow is being traced.
+
+What will *not* be decoded with the qq option:
+
+ - everything except instruction pointer associated with PSB packets
+
+What *will* be decoded with the qq option:
+
+ - instruction pointer associated with PSB packets
+
dump option
~~~~~~~~~~~