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| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2010-06-03 18:26:24 +0800 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2010-07-20 22:05:34 -0400 |
| commit | bc289ae98b75d93228d24f521ef02a076e506e94 (patch) | |
| tree | 50d151d0fbde1b106932c0f80a2639839d261ca3 /include/linux/ftrace_event.h | |
| parent | 985023dee6e212493831431ba2e3ce8918f001b2 (diff) | |
| download | lwn-bc289ae98b75d93228d24f521ef02a076e506e94.tar.gz lwn-bc289ae98b75d93228d24f521ef02a076e506e94.zip | |
tracing: Reduce latency and remove percpu trace_seq
__print_flags() and __print_symbolic() use percpu trace_seq:
1) Its memory is allocated at compile time, it wastes memory if we don't use tracing.
2) It is percpu data and it wastes more memory for multi-cpus system.
3) It disables preemption when it executes its core routine
"trace_seq_printf(s, "%s: ", #call);" and introduces latency.
So we move this trace_seq to struct trace_iterator.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4C078350.7090106@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ftrace_event.h')
| -rw-r--r-- | include/linux/ftrace_event.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 2b7b1395b4d5..02b8b24f8f51 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -11,8 +11,6 @@ struct trace_array; struct tracer; struct dentry; -DECLARE_PER_CPU(struct trace_seq, ftrace_event_seq); - struct trace_print_flags { unsigned long mask; const char *name; @@ -58,6 +56,9 @@ struct trace_iterator { struct ring_buffer_iter *buffer_iter[NR_CPUS]; unsigned long iter_flags; + /* trace_seq for __print_flags() and __print_symbolic() etc. */ + struct trace_seq tmp_seq; + /* The below is zeroed out in pipe_read */ struct trace_seq seq; struct trace_entry *ent; |