2009-12-15 06:09:31 +08:00
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perf-diff(1)
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2010-05-05 22:23:27 +08:00
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============
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2009-12-15 06:09:31 +08:00
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NAME
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----
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2009-12-15 17:24:08 +08:00
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perf-diff - Read two perf.data files and display the differential profile
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2009-12-15 06:09:31 +08:00
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SYNOPSIS
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--------
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[verse]
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'perf diff' [oldfile] [newfile]
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DESCRIPTION
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-----------
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2009-12-15 17:24:08 +08:00
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This command displays the performance difference amongst two perf.data files
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2009-12-15 06:09:31 +08:00
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captured via perf record.
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If no parameters are passed it will assume perf.data.old and perf.data.
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2012-09-06 23:46:55 +08:00
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The differential profile is displayed only for events matching both
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specified perf.data files.
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2009-12-15 06:09:31 +08:00
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OPTIONS
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-------
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2010-12-01 09:57:12 +08:00
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-M::
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--displacement::
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Show position displacement relative to baseline.
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-D::
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--dump-raw-trace::
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Dump raw trace in ASCII.
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-m::
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--modules::
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Load module symbols. WARNING: use only with -k and LIVE kernel
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perf diff: Use perf_session__fprintf_hists just like 'perf record'
That means that almost everything you can do with 'perf report'
can be done with 'perf diff', for instance:
$ perf record -f find / > /dev/null
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data (~2699
samples) ] $ perf record -f find / > /dev/null
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data (~2687
samples) ] perf diff | head -8
9.02% +1.00% find libc-2.10.1.so [.] _IO_vfprintf_internal
2.91% -1.00% find [kernel] [k] __kmalloc
2.85% -1.00% find [kernel] [k] ext4_htree_store_dirent
1.99% -1.00% find [kernel] [k] _atomic_dec_and_lock
2.44% find [kernel] [k] half_md4_transform
$
So if you want to zoom into libc:
$ perf diff --dsos libc-2.10.1.so | head -8
37.34% find [.] _IO_vfprintf_internal
10.34% find [.] __GI_memmove
8.25% +2.00% find [.] _int_malloc
5.07% -1.00% find [.] __GI_mempcpy
7.62% +2.00% find [.] _int_free
$
And if there were multiple commands using libc, it is also
possible to aggregate them all by using --sort symbol:
$ perf diff --dsos libc-2.10.1.so --sort symbol | head -8
37.34% [.] _IO_vfprintf_internal
10.34% [.] __GI_memmove
8.25% +2.00% [.] _int_malloc
5.07% -1.00% [.] __GI_mempcpy
7.62% +2.00% [.] _int_free
$
The displacement column now is off by default, to use it:
perf diff -m --dsos libc-2.10.1.so --sort symbol | head -8
37.34% [.] _IO_vfprintf_internal
10.34% [.] __GI_memmove
8.25% +2.00% [.] _int_malloc
5.07% -1.00% +2 [.] __GI_mempcpy
7.62% +2.00% -1 [.] _int_free
$
Using -t/--field-separator can be used for scripting:
$ perf diff -t, -m --dsos libc-2.10.1.so --sort symbol | head -8
37.34, , ,[.] _IO_vfprintf_internal
10.34, , ,[.] __GI_memmove
8.25,+2.00%, ,[.] _int_malloc
5.07,-1.00%, +2,[.] __GI_mempcpy
7.62,+2.00%, -1,[.] _int_free
6.99,+1.00%, -1,[.] _IO_new_file_xsputn
1.89,-2.00%, +4,[.] __readdir64
$
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1260978567-550-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16 23:49:27 +08:00
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-d::
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--dsos=::
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Only consider symbols in these dsos. CSV that understands
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file://filename entries.
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-C::
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--comms=::
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Only consider symbols in these comms. CSV that understands
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file://filename entries.
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-S::
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--symbols=::
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Only consider these symbols. CSV that understands
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file://filename entries.
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-s::
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--sort=::
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Sort by key(s): pid, comm, dso, symbol.
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-t::
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--field-separator=::
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Use a special separator character and don't pad with spaces, replacing
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2010-12-01 09:57:12 +08:00
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all occurrences of this separator in symbol names (and other output)
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perf diff: Use perf_session__fprintf_hists just like 'perf record'
That means that almost everything you can do with 'perf report'
can be done with 'perf diff', for instance:
$ perf record -f find / > /dev/null
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data (~2699
samples) ] $ perf record -f find / > /dev/null
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.062 MB perf.data (~2687
samples) ] perf diff | head -8
9.02% +1.00% find libc-2.10.1.so [.] _IO_vfprintf_internal
2.91% -1.00% find [kernel] [k] __kmalloc
2.85% -1.00% find [kernel] [k] ext4_htree_store_dirent
1.99% -1.00% find [kernel] [k] _atomic_dec_and_lock
2.44% find [kernel] [k] half_md4_transform
$
So if you want to zoom into libc:
$ perf diff --dsos libc-2.10.1.so | head -8
37.34% find [.] _IO_vfprintf_internal
10.34% find [.] __GI_memmove
8.25% +2.00% find [.] _int_malloc
5.07% -1.00% find [.] __GI_mempcpy
7.62% +2.00% find [.] _int_free
$
And if there were multiple commands using libc, it is also
possible to aggregate them all by using --sort symbol:
$ perf diff --dsos libc-2.10.1.so --sort symbol | head -8
37.34% [.] _IO_vfprintf_internal
10.34% [.] __GI_memmove
8.25% +2.00% [.] _int_malloc
5.07% -1.00% [.] __GI_mempcpy
7.62% +2.00% [.] _int_free
$
The displacement column now is off by default, to use it:
perf diff -m --dsos libc-2.10.1.so --sort symbol | head -8
37.34% [.] _IO_vfprintf_internal
10.34% [.] __GI_memmove
8.25% +2.00% [.] _int_malloc
5.07% -1.00% +2 [.] __GI_mempcpy
7.62% +2.00% -1 [.] _int_free
$
Using -t/--field-separator can be used for scripting:
$ perf diff -t, -m --dsos libc-2.10.1.so --sort symbol | head -8
37.34, , ,[.] _IO_vfprintf_internal
10.34, , ,[.] __GI_memmove
8.25,+2.00%, ,[.] _int_malloc
5.07,-1.00%, +2,[.] __GI_mempcpy
7.62,+2.00%, -1,[.] _int_free
6.99,+1.00%, -1,[.] _IO_new_file_xsputn
1.89,-2.00%, +4,[.] __readdir64
$
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1260978567-550-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16 23:49:27 +08:00
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with a '.' character, that thus it's the only non valid separator.
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2009-12-15 06:09:31 +08:00
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-v::
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--verbose::
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2009-12-15 17:24:08 +08:00
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Be verbose, for instance, show the raw counts in addition to the
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2009-12-15 06:09:31 +08:00
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diff.
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2009-12-15 21:01:22 +08:00
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2010-12-01 09:57:12 +08:00
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-f::
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--force::
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Don't complain, do it.
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2010-12-10 04:27:07 +08:00
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--symfs=<directory>::
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Look for files with symbols relative to this directory.
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2010-12-01 09:57:12 +08:00
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2012-10-05 22:44:40 +08:00
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-b::
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--baseline-only::
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Show only items with match in baseline.
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2012-10-05 22:44:41 +08:00
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-c::
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--compute::
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2012-10-05 22:44:43 +08:00
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Differential computation selection - delta,ratio,wdiff (default is delta).
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2012-10-05 22:44:42 +08:00
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If '+' is specified as a first character, the output is sorted based
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on the computation results.
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2012-10-05 22:44:41 +08:00
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See COMPARISON METHODS section for more info.
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COMPARISON METHODS
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------------------
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delta
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~~~~~
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If specified the 'Delta' column is displayed with value 'd' computed as:
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d = A->period_percent - B->period_percent
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with:
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- A/B being matching hist entry from first/second file specified
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(or perf.data/perf.data.old) respectively.
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- period_percent being the % of the hist entry period value within
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single data file
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ratio
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~~~~~
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If specified the 'Ratio' column is displayed with value 'r' computed as:
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r = A->period / B->period
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with:
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- A/B being matching hist entry from first/second file specified
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(or perf.data/perf.data.old) respectively.
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- period being the hist entry period value
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2012-10-05 22:44:43 +08:00
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wdiff
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~~~~~
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If specified the 'Weighted diff' column is displayed with value 'd' computed as:
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d = B->period * WEIGHT-A - A->period * WEIGHT-B
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- A/B being matching hist entry from first/second file specified
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(or perf.data/perf.data.old) respectively.
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- period being the hist entry period value
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- WEIGHT-A/WEIGHT-B being user suplied weights in the the '-c' option
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behind ':' separator like '-c wdiff:1,2'.
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2012-10-05 22:44:41 +08:00
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2009-12-15 06:09:31 +08:00
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SEE ALSO
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--------
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linkperf:perf-record[1]
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