perf diff: Percent calcs should use double values
Otherwise we do integer math and the delta values round up to
multiples of 1.0%.
Also, calculate absolute values. Things look precise now:
$ perf report -i perf.data.old --sort dso,symbol | head -13
9.02% libc-2.10.1.so [.] _IO_vfprintf_internal
4.88% find [.] 0x00000000014af0
2.91% [kernel] [k] __kmalloc
2.85% [kernel] [k] ext4_htree_store_dirent
2.50% libc-2.10.1.so [.] __GI_memmove
2.44% [kernel] [k] half_md4_transform
2.43% [kernel] [k] _spin_lock
2.33% [kernel] [k] system_call
$ perf report -i perf.data --sort dso,symbol | head -13
8.55% libc-2.10.1.so [.] _IO_vfprintf_internal
3.11% [kernel] [k] __kmalloc
3.07% [kernel] [k] ext4_htree_store_dirent
2.66% find [.] 0x00000000016bcf
2.61% [kernel] [k] _atomic_dec_and_lock
2.46% [kernel] [k] half_md4_transform
2.41% libc-2.10.1.so [.] __GI_memmove
2.30% find [.] 0x00000000009219
$ perf diff | head -13
9.02% -0.47% libc-2.10.1.so [.] _IO_vfprintf_internal
2.91% +0.20% [kernel] [k] __kmalloc
2.85% +0.23% [kernel] [k] ext4_htree_store_dirent
1.99% +0.62% [kernel] [k] _atomic_dec_and_lock
2.44% +0.02% [kernel] [k] half_md4_transform
2.50% -0.09% libc-2.10.1.so [.] __GI_memmove
1.88% +0.01% [kernel] [k] __d_lookup
2.43% -0.75% [kernel] [k] _spin_lock
0.97% +0.62% [kernel] [k] path_get
1.99% -0.42% libc-2.10.1.so [.] _int_malloc
$
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: <1260981109-2621-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
1 file changed