With 'perf script' it is common that we just want to add or remove a field.
Currently this requires figuring out the long list of default fields and
specifying them first, and then adding/removing the new field.
This patch adds a new + - syntax to merely add or remove fields,
that allows more succint and clearer command lines
For example to remove the comm field from PMU samples:
Previously
$ perf script -F tid,cpu,time,event,sym,ip,dso,period | head -1
swapper 0 [000] 504345.383126: 1 cycles: ffffffff90060c66 native_write_msr ([kernel.kallsyms])
with the new syntax
perf script -F -comm | head -1
0 [000] 504345.383126: 1 cycles: ffffffff90060c66 native_write_msr ([kernel.kallsyms])
The new syntax cannot be mixed with normal overriding.
v2: Fix example in description. Use tid vs pid. No functional changes.
v3: Don't skip initialization when user specified explicit type.
v4: Rebase. Remove empty line.
Committer testing:
# perf record -a usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 1.748 MB perf.data (14 samples) ]
Without a explicit field list specified via -F, defaults to:
# perf script | head -2
perf 6338 [000] 18467.058607: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
swapper 0 [001] 18467.058617: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
#
Which is equivalent to:
# perf script -F comm,tid,cpu,time,period,event,ip,sym,dso | head -2
perf 6338 [000] 18467.058607: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
swapper 0 [001] 18467.058617: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
#
So if we want to remove the comm, as in your original example, we would have to
figure out the default field list and remove ' comm' from it:
# perf script -F tid,cpu,time,period,event,ip,sym,dso | head -2
6338 [000] 18467.058607: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
0 [001] 18467.058617: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
#
With your patch this becomes simpler, one can remove fields by prefixing them
with '-':
# perf script -F -comm | head -2
6338 [000] 18467.058607: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
0 [001] 18467.058617: 1 cycles: ffffffff89060c36 native_write_msr (/lib/modules/4.11.0-rc8+/build/vmlinux)
#
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Milian Wolff <milian.wolff@kdab.com>
Link: http://lkml.kernel.org/r/20170602154810.15875-1-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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