forge/linux-pinenote
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

perf, x86: Improve the PEBS ABI

Browse source 
Rename perf_event_attr::precise to perf_event_attr::precise_ip and
widen it to 2 bits. This new field describes the required precision of
the PERF_SAMPLE_IP field:

  0 - SAMPLE_IP can have arbitrary skid
  1 - SAMPLE_IP must have constant skid
  2 - SAMPLE_IP requested to have 0 skid
  3 - SAMPLE_IP must have 0 skid

And modify the Intel PEBS code accordingly. The PEBS implementation
now supports up to precise_ip == 2, where we perform the IP fixup.

Also s/PERF_RECORD_MISC_EXACT/&_IP/ to clarify its meaning, this bit
should be set for each PERF_SAMPLE_IP field known to match the actual
instruction triggering the event.

This new scheme allows for a PEBS mode that uses the buffer for more
than a single event.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-04-08 23:03:20 +02:00 • committed by Ingo Molnar
commit ab608344bc
6 changed files with 59 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

25
tools/perf/util/parse-events.c
View file

@ -654,10 +654,6 @@ parse_raw_event(const char **strp, struct perf_event_attr *attr)
return EVT_FAILED;
n = hex2u64(str + 1, &config);
if (n > 0) {
if (str[n+1] == 'p') {
attr->precise = 1;
n++;
}
*strp = str + n + 1;
attr->type = PERF_TYPE_RAW;
attr->config = config;
@ -692,19 +688,29 @@ static enum event_result
parse_event_modifier(const char **strp, struct perf_event_attr *attr)
{
const char *str = *strp;
int eu = 1, ek = 1, eh = 1;
int exclude = 0;
int eu = 0, ek = 0, eh = 0, precise = 0;
if (*str++ != ':')
return 0;
while (*str) {
if (*str == 'u')
if (*str == 'u') {
if (!exclude)
exclude = eu = ek = eh = 1;
eu = 0;
else if (*str == 'k')
} else if (*str == 'k') {
if (!exclude)
exclude = eu = ek = eh = 1;
ek = 0;
else if (*str == 'h')
} else if (*str == 'h') {
if (!exclude)
exclude = eu = ek = eh = 1;
eh = 0;
else
} else if (*str == 'p') {
precise++;
} else
break;
++str;
}
if (str >= *strp + 2) {
@ -712,6 +718,7 @@ parse_event_modifier(const char **strp, struct perf_event_attr *attr)
attr->exclude_user = eu;
attr->exclude_kernel = ek;
attr->exclude_hv = eh;
attr->precise_ip = precise;
return 1;
}
return 0;