diff options
Diffstat (limited to 'tools/perf/Documentation/perf-stat.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-stat.txt | 60 |
1 files changed, 35 insertions, 25 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index db420dd75e43..9f9f29025e49 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -166,6 +166,11 @@ use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'. If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'. +--for-each-cgroup name:: +Expand event list for each cgroup in "name" (allow multiple cgroups separated +by comma). This has same effect that repeating -e option and -G option for +each event x name. This option cannot be used with -G/--cgroup option. + -o file:: --output file:: Print the output into the designated file. @@ -180,43 +185,45 @@ with it. --append may be used here. Examples: 3>results perf stat --log-fd 3 -- $cmd 3>>results perf stat --log-fd 3 --append -- $cmd ---control fd:ctl-fd[,ack-fd] +--control=fifo:ctl-fifo[,ack-fifo]:: +--control=fd:ctl-fd[,ack-fd]:: +ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows. Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events). Measurements can be started with events disabled using --delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor to synchronize with the controlling process. Example of bash shell script to enable and disable events during measurements: -#!/bin/bash + #!/bin/bash -ctl_dir=/tmp/ + ctl_dir=/tmp/ -ctl_fifo=${ctl_dir}perf_ctl.fifo -test -p ${ctl_fifo} && unlink ${ctl_fifo} -mkfifo ${ctl_fifo} -exec {ctl_fd}<>${ctl_fifo} + ctl_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} + 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=$! + perf stat -D -1 -e cpu-cycles -a -I 1000 \ + --control fd:${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})" + 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_ack}>&- + unlink ${ctl_ack_fifo} -exec {ctl_fd}>&- -unlink ${ctl_fifo} + exec {ctl_fd}>&- + unlink ${ctl_fifo} -wait -n ${perf_pid} -exit $? + wait -n ${perf_pid} + exit $? --pre:: @@ -361,6 +368,11 @@ if the workload is actually bound by the CPU and not by something else. For best results it is usually a good idea to use it with interval mode like -I 1000, as the bottleneck of workloads can change often. +This enables --metric-only, unless overridden with --no-metric-only. + +The following restrictions only apply to older Intel CPUs and Atom, +on newer CPUs (IceLake and later) TopDown can be collected for any thread: + The top down metrics are collected per core instead of per CPU thread. Per core mode is automatically enabled and -a (global monitoring) is needed, requiring root rights or @@ -372,8 +384,6 @@ echo 0 > /proc/sys/kernel/nmi_watchdog for best results. Otherwise the bottlenecks may be inconsistent on workload with changing phases. -This enables --metric-only, unless overridden with --no-metric-only. - To interpret the results it is usually needed to know on which CPUs the workload runs on. If needed the CPUs can be forced using taskset. |