diff options
author | Ingo Molnar <mingo@elte.hu> | 2009-11-23 10:57:59 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-11-23 11:48:27 +0100 |
commit | a4234bfcf4d72a10a99176cdef007345e9c3b4aa (patch) | |
tree | 240da1dbbdd6d2f88e9491774e623dc82caaa911 /lib/crc16.c | |
parent | 6e3d8330ae2c4b2c11a9577a0130d2ecda1c610d (diff) |
perf_events: Optimize the swcounter hotpath
The structure init creates a bit memcpy, which shows
up big time in perf annotate output:
: ffffffff810a859d <__perf_sw_event>:
1.68 : ffffffff810a859d: 55 push %rbp
1.69 : ffffffff810a859e: 41 89 fa mov %edi,%r10d
0.01 : ffffffff810a85a1: 49 89 c9 mov %rcx,%r9
0.00 : ffffffff810a85a4: 31 c0 xor %eax,%eax
1.71 : ffffffff810a85a6: b9 16 00 00 00 mov $0x16,%ecx
0.00 : ffffffff810a85ab: 48 89 e5 mov %rsp,%rbp
0.00 : ffffffff810a85ae: 48 83 ec 60 sub $0x60,%rsp
1.52 : ffffffff810a85b2: 48 8d 7d a0 lea -0x60(%rbp),%rdi
85.20 : ffffffff810a85b6: f3 ab rep stos %eax,%es:(%rdi)
None of the callees depends on the structure being pre-initialized,
so only initialize ->addr. This gets rid of the memcpy overhead.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib/crc16.c')
0 files changed, 0 insertions, 0 deletions