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| author | Ingo Molnar <mingo@elte.hu> | 2009-11-23 10:57:59 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-11-23 11:48:27 +0100 |
| commit | a4234bfcf4d72a10a99176cdef007345e9c3b4aa (patch) | |
| tree | 240da1dbbdd6d2f88e9491774e623dc82caaa911 /kernel | |
| parent | 6e3d8330ae2c4b2c11a9577a0130d2ecda1c610d (diff) | |
| download | blackbird-op-linux-a4234bfcf4d72a10a99176cdef007345e9c3b4aa.tar.gz blackbird-op-linux-a4234bfcf4d72a10a99176cdef007345e9c3b4aa.zip | |
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 'kernel')
| -rw-r--r-- | kernel/perf_event.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index abe1ef47496c..20df8aba8da5 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3954,12 +3954,12 @@ out: void __perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr) { - struct perf_sample_data data = { - .addr = addr, - }; + struct perf_sample_data data; - do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, - &data, regs); + data.addr = addr; + data.raw = NULL; + + do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs); } static void perf_swevent_read(struct perf_event *event) |
