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perf report: Add front-entry cache for lookups 

Before:

 Performance counter stats for './perf report -i perf.data.big':

     12453988058  instructions

 Performance counter stats for './perf report -i perf.data.big':

     12379566017  instructions

0.60% reduction.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-06-03 19:59:24 +02:00
parent 44db76c855
commit eed4dcd443
1 changed files with 14 additions and 1 deletions
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15
Documentation/perf_counter/builtin-report.c
View File

@ -229,6 +229,7 @@ static int thread__set_comm(struct thread *self, const char *comm)
}
static struct rb_root threads;
static struct thread *last_match;
static struct thread *threads__findnew(pid_t pid)
{
@ -236,12 +237,22 @@ static struct thread *threads__findnew(pid_t pid)
struct rb_node *parent = NULL;
struct thread *th;
/*
* Font-end cache - PID lookups come in blocks,
* so most of the time we dont have to look up
* the full rbtree:
*/
if (last_match && last_match->pid == pid)
return last_match;
while (*p != NULL) {
parent = *p;
th = rb_entry(parent, struct thread, rb_node);
if (th->pid == pid)
if (th->pid == pid) {
last_match = th;
return th;
}
if (pid < th->pid)
p = &(*p)->rb_left;
@ -253,7 +264,9 @@ static struct thread *threads__findnew(pid_t pid)
if (th != NULL) {
rb_link_node(&th->rb_node, parent, p);
rb_insert_color(&th->rb_node, &threads);
last_match = th;
}
return th;
}