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PERF_4.4-TRACE(1) | perf Manual | PERF_4.4-TRACE(1) |
NAME¶
perf-trace - strace inspired toolSYNOPSIS¶
perf trace perf trace record
DESCRIPTION¶
This command will show the events associated with the target, initially syscalls, but other system events like pagefaults, task lifetime events, scheduling events, etc. This is a live mode tool in addition to working with perf.data files like the other perf tools. Files can be generated using the perf record command but the session needs to include the raw_syscalls events (-e raw_syscalls:*). Alternatively, perf trace record can be used as a shortcut to automatically include the raw_syscalls events when writing events to a file. The following options apply to perf trace; options to perf trace record are found in the perf record man page.OPTIONS¶
-a, --all-cpusSystem-wide collection from all CPUs.
-e, --expr
List of syscalls to show, currently only syscall names.
Prefixing with ! shows all syscalls but the ones specified. You may need to
escape it.
-o, --output=
Output file name.
-p, --pid=
Record events on existing process ID (comma separated
list).
-t, --tid=
Record events on existing thread ID (comma separated
list).
-u, --uid=
Record events in threads owned by uid. Name or
number.
--filter-pids=
Filter out events for these pids and for trace
itself (comma separated list).
-v, --verbose=
Verbosity level.
--no-inherit
Child tasks do not inherit counters.
-m, --mmap-pages=
Number of mmap data pages (must be a power of two) or
size specification with appended unit character - B/K/M/G. The size is rounded
up to have nearest pages power of two value.
-C, --cpu
Collect samples only on the list of CPUs provided.
Multiple CPUs can be provided as a comma-separated list with no space: 0,1.
Ranges of CPUs are specified with -: 0-2. In per-thread mode with inheritance
mode on (default), Events are captured only when the thread executes on the
designated CPUs. Default is to monitor all CPUs.
--duration: Show only events that had a duration greater than N.M ms.
--sched: Accrue thread runtime and provide a summary at the end of the session.
-i --input Process events from a given perf data file.
-T --time Print full timestamp rather time relative to first sample.
--comm
Show process COMM right beside its ID, on by default,
disable with --no-comm.
-s, --summary
Show only a summary of syscalls by thread with min, max,
and average times (in msec) and relative stddev.
-S, --with-summary
Show all syscalls followed by a summary by thread with
min, max, and average times (in msec) and relative stddev.
--tool_stats
Show tool stats such as number of times
fd→pathname was discovered thru hooking the open syscall return +
vfs_getname or via reading /proc/pid/fd, etc.
-F=[all|min|maj], --pf=[all|min|maj]
Trace pagefaults. Optionally, you can specify whether you
want minor, major or all pagefaults. Default value is maj.
--syscalls
Trace system calls. This options is enabled by
default.
--event
Trace other events, see perf list for a complete
list.
--proc-map-timeout
When processing pre-existing threads /proc/XXX/mmap, it
may take a long time, because the file may be huge. A time out is needed in
such cases. This option sets the time out limit. The default value is 500
ms.
PAGEFAULTS¶
When tracing pagefaults, the format of the trace is as follows: <min|maj>fault [<ip.symbol>+<ip.offset>] ⇒ < addr.dso@addr.offset[1]> (<map type><addr level>).•min/maj indicates whether fault event is minor or
major;
•ip.symbol shows symbol for instruction pointer
(the code that generated the fault); if no debug symbols available, perf trace
will print raw IP;
•addr.dso shows DSO for the faulted address;
•map type is either d for non-executable
maps or x for executable maps;
•addr level is either k for kernel dso or
. for user dso.
For symbols resolution you may need to install debugging symbols.
Please be aware that duration is currently always 0 and doesn’t reflect
actual time it took for fault to be handled!
When --verbose specified, perf trace tries to print all available information
for both IP and fault address in the form of dso@symbol[2]+offset.
EXAMPLES¶
Trace only major pagefaults:$ perf trace --no-syscalls -F
$ perf trace -F all
1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)
As you can see, there was major pagefault in python process, from CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
SEE ALSO¶
perf_4.4-record(1), perf_4.4-script(1)NOTES¶
- 1.
- addr.dso@addr.offset
mailto:addr.dso@addr.offset
- 2.
- dso@symbol
mailto:dso@symbol
2016-03-20 | perf |