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author | Paolo Bonzini <pbonzini@redhat.com> | 2020-09-11 13:12:11 -0400 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-09-11 13:12:11 -0400 |
commit | 1b67fd086dd7be076f190dfe4b52403d0cf58375 (patch) | |
tree | b7ea623c62bd8b1a1310c5e9d24dbf155a9d04aa /tools/perf/Documentation/perf-stat.txt | |
parent | b5331379bc62611d1026173a09c73573384201d9 (diff) | |
parent | 7b75cd5128421c673153efb1236705696a1a9812 (diff) |
Merge tag 'kvmarm-fixes-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for Linux 5.9, take #1
- Multiple stolen time fixes, with a new capability to match x86
- Fix for hugetlbfs mappings when PUD and PMD are the same level
- Fix for hugetlbfs mappings when PTE mappings are enforced
(dirty logging, for example)
- Fix tracing output of 64bit values
Diffstat (limited to 'tools/perf/Documentation/perf-stat.txt')
-rw-r--r-- | tools/perf/Documentation/perf-stat.txt | 44 |
1 files changed, 42 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index b029ee728a0b..c9bfefc051fb 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -176,6 +176,45 @@ with it. --append may be used here. Examples: 3>results perf stat --log-fd 3 -- $cmd 3>>results perf stat --log-fd 3 --append -- $cmd +--control fd:ctl-fd[,ack-fd] +Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, +'disable': disable events). Measurements can be started with events disabled using +--delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor +to synchronize with the controlling process. Example of bash shell script to enable and +disable events during measurements: + +#!/bin/bash + +ctl_dir=/tmp/ + +ctl_fifo=${ctl_dir}perf_ctl.fifo +test -p ${ctl_fifo} && unlink ${ctl_fifo} +mkfifo ${ctl_fifo} +exec {ctl_fd}<>${ctl_fifo} + +ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo +test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo} +mkfifo ${ctl_ack_fifo} +exec {ctl_fd_ack}<>${ctl_ack_fifo} + +perf stat -D -1 -e cpu-cycles -a -I 1000 \ + --control fd:${ctl_fd},${ctl_fd_ack} \ + -- sleep 30 & +perf_pid=$! + +sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})" +sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})" + +exec {ctl_fd_ack}>&- +unlink ${ctl_ack_fifo} + +exec {ctl_fd}>&- +unlink ${ctl_fifo} + +wait -n ${perf_pid} +exit $? + + --pre:: --post:: Pre and post measurement hooks, e.g.: @@ -238,8 +277,9 @@ mode, use --per-node in addition to -a. (system-wide). -D msecs:: --delay msecs:: -After starting the program, wait msecs before measuring. This is useful to -filter out the startup phase of the program, which is often very different. +After starting the program, wait msecs before measuring (-1: start with events +disabled). This is useful to filter out the startup phase of the program, +which is often very different. -T:: --transaction:: |