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Diffstat (limited to 'tools/perf/Documentation/perf-trace.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-trace.txt | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt index 115db9e06ecd..e113450503d2 100644 --- a/tools/perf/Documentation/perf-trace.txt +++ b/tools/perf/Documentation/perf-trace.txt @@ -171,6 +171,11 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs. --kernel-syscall-graph:: Show the kernel callchains on the syscall exit path. +--max-events=N:: + Stop after processing N events. Note that strace-like events are considered + only at exit time or when a syscall is interrupted, i.e. in those cases this + option is equivalent to the number of lines printed. + --max-stack:: Set the stack depth limit when parsing the callchain, anything beyond the specified depth will be ignored. Note that at this point @@ -238,6 +243,68 @@ Trace syscalls, major and minor pagefaults: As you can see, there was major pagefault in python process, from CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so. +Trace the first 4 open, openat or open_by_handle_at syscalls (in the future more syscalls may match here): + + $ perf trace -e open* --max-events 4 + [root@jouet perf]# trace -e open* --max-events 4 + 2272.992 ( 0.037 ms): gnome-shell/1370 openat(dfd: CWD, filename: /proc/self/stat) = 31 + 2277.481 ( 0.139 ms): gnome-shell/3039 openat(dfd: CWD, filename: /proc/self/stat) = 65 + 3026.398 ( 0.076 ms): gnome-shell/3039 openat(dfd: CWD, filename: /proc/self/stat) = 65 + 4294.665 ( 0.015 ms): sed/15879 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC) = 3 + $ + +Trace the first minor page fault when running a workload: + + # perf trace -F min --max-stack=7 --max-events 1 sleep 1 + 0.000 ( 0.000 ms): sleep/18006 minfault [__clear_user+0x1a] => 0x5626efa56080 (?k) + __clear_user ([kernel.kallsyms]) + load_elf_binary ([kernel.kallsyms]) + search_binary_handler ([kernel.kallsyms]) + __do_execve_file.isra.33 ([kernel.kallsyms]) + __x64_sys_execve ([kernel.kallsyms]) + do_syscall_64 ([kernel.kallsyms]) + entry_SYSCALL_64 ([kernel.kallsyms]) + # + +Trace the next min page page fault to take place on the first CPU: + + # perf trace -F min --call-graph=dwarf --max-events 1 --cpu 0 + 0.000 ( 0.000 ms): Web Content/17136 minfault [js::gc::Chunk::fetchNextDecommittedArena+0x4b] => 0x7fbe6181b000 (?.) + js::gc::FreeSpan::initAsEmpty (inlined) + js::gc::Arena::setAsNotAllocated (inlined) + js::gc::Chunk::fetchNextDecommittedArena (/usr/lib64/firefox/libxul.so) + js::gc::Chunk::allocateArena (/usr/lib64/firefox/libxul.so) + js::gc::GCRuntime::allocateArena (/usr/lib64/firefox/libxul.so) + js::gc::ArenaLists::allocateFromArena (/usr/lib64/firefox/libxul.so) + js::gc::GCRuntime::tryNewTenuredThing<JSString, (js::AllowGC)1> (inlined) + js::AllocateString<JSString, (js::AllowGC)1> (/usr/lib64/firefox/libxul.so) + js::Allocate<JSThinInlineString, (js::AllowGC)1> (inlined) + JSThinInlineString::new_<(js::AllowGC)1> (inlined) + AllocateInlineString<(js::AllowGC)1, unsigned char> (inlined) + js::ConcatStrings<(js::AllowGC)1> (/usr/lib64/firefox/libxul.so) + [0x18b26e6bc2bd] (/tmp/perf-17136.map) + # + +Trace the next two sched:sched_switch events, four block:*_plug events, the +next block:*_unplug and the next three net:*dev_queue events, this last one +with a backtrace of at most 16 entries, system wide: + + # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/ + 0.000 :0/0 sched:sched_switch:swapper/2:0 [120] S ==> rcu_sched:10 [120] + 0.015 rcu_sched/10 sched:sched_switch:rcu_sched:10 [120] R ==> swapper/2:0 [120] + 254.198 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051f600 len=66 + __dev_queue_xmit ([kernel.kallsyms]) + 273.977 :0/0 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051f600 len=78 + __dev_queue_xmit ([kernel.kallsyms]) + 274.007 :0/0 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051ff00 len=78 + __dev_queue_xmit ([kernel.kallsyms]) + 2930.140 kworker/u16:58/2722 block:block_plug:[kworker/u16:58] + 2930.162 kworker/u16:58/2722 block:block_unplug:[kworker/u16:58] 1 + 4466.094 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8] + 8050.123 kworker/u16:30/2694 block:block_plug:[kworker/u16:30] + 8050.271 kworker/u16:30/2694 block:block_plug:[kworker/u16:30] + # + SEE ALSO -------- linkperf:perf-record[1], linkperf:perf-script[1] |