diff options
Diffstat (limited to 'tools/perf/Documentation/perf-intel-pt.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-intel-pt.txt | 53 |
1 files changed, 50 insertions, 3 deletions
diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt index d5a266d7f15b..cd362dc2af07 100644 --- a/tools/perf/Documentation/perf-intel-pt.txt +++ b/tools/perf/Documentation/perf-intel-pt.txt @@ -112,6 +112,32 @@ The flags are "bcrosyiABEx" which stand for branch, call, return, conditional, system, asynchronous, interrupt, transaction abort, trace begin, trace end, and in transaction, respectively. +perf script also supports higher level ways to dump instruction traces: + + perf script --insn-trace --xed + +Dump all instructions. This requires installing the xed tool (see XED below) +Dumping all instructions in a long trace can be fairly slow. It is usually better +to start with higher level decoding, like + + perf script --call-trace + +or + + perf script --call-ret-trace + +and then select a time range of interest. The time range can then be examined +in detail with + + perf script --time starttime,stoptime --insn-trace --xed + +While examining the trace it's also useful to filter on specific CPUs using +the -C option + + perf script --time starttime,stoptime --insn-trace --xed -C 1 + +Dump all instructions in time range on CPU 1. + Another interesting field that is not printed by default is 'ipc' which can be displayed as follows: @@ -558,7 +584,7 @@ The mmap size and auxtrace mmap size are displayed if the -vv option is used e.g Intel PT modes of operation ~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Intel PT can be used in 2 modes: +Intel PT can be used in 3 modes: full-trace mode sample mode snapshot mode @@ -571,7 +597,8 @@ Sample mode attaches a Intel PT sample to other events e.g. perf record --aux-sample -e intel_pt//u -e branch-misses:u -Snapshot mode captures the available data when a signal is sent e.g. +Snapshot mode captures the available data when a signal is sent or "snapshot" +control command is issued. e.g. using a signal perf record -v -e intel_pt//u -S ./loopy 1000000000 & [1] 11435 @@ -582,7 +609,23 @@ Note that the signal sent is SIGUSR2. Note that "Recording AUX area tracing snapshot" is displayed because the -v option is used. -The 2 modes cannot be used together. +The advantage of using "snapshot" control command is that the access is +controlled by access to a FIFO e.g. + + $ mkfifo perf.control + $ mkfifo perf.ack + $ cat perf.ack & + [1] 15235 + $ sudo ~/bin/perf record --control fifo:perf.control,perf.ack -S -e intel_pt//u -- sleep 60 & + [2] 15243 + $ ps -e | grep perf + 15244 pts/1 00:00:00 perf + $ kill -USR2 15244 + bash: kill: (15244) - Operation not permitted + $ echo snapshot > perf.control + ack + +The 3 Intel PT modes of operation cannot be used together. Buffer handling @@ -1093,6 +1136,10 @@ To display PEBS events from the Intel PT trace, use the itrace 'o' option e.g. perf script --itrace=oe +XED +--- + +include::build-xed.txt[] SEE ALSO -------- |