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x86, perf: P4 PMU - Fix typos in comments and style cleanup

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This patch:

 - fixes typos in comments and clarifies the text
 - renames obscure p4_event_alias::original and ::alter members to
   ::original and ::alternative as appropriate
 - drops parenthesis from the return of p4_get_alias_event()

No functional changes.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/20110721160625.GX7492@sun
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Cyrill Gorcunov 2011-07-21 20:06:25 +04:00 committed by Ingo Molnar
parent baf040a0d1
commit f53173e47d
2 changed files with 31 additions and 37 deletions
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2
arch/x86/include/asm/perf_event_p4.h
View File

@ -133,7 +133,7 @@
/*
* In case of event aliasing we need to preserve some
* caller bits otherwise the mapping won't be complete.
* caller bits, otherwise the mapping won't be complete.
*/
#define P4_CONFIG_EVENT_ALIAS_MASK \
(p4_config_pack_escr(P4_CONFIG_MASK_ESCR) | \

66
arch/x86/kernel/cpu/perf_event_p4.c
View File

@ -571,35 +571,34 @@ static __initconst const u64 p4_hw_cache_event_ids
};
/*
* Because of Netburst being quite restricted in now
* many same events can run simultaneously, we use
* event aliases, ie different events which have the
* same functionallity but use non-intersected resources
* (ESCR/CCCR/couter registers). This allow us to run
* two or more semi-same events together. It is done
* transparently to a user space.
* Because of Netburst being quite restricted in how many
* identical events may run simultaneously, we introduce event aliases,
* ie the different events which have the same functionality but
* utilize non-intersected resources (ESCR/CCCR/counter registers).
*
* Never set any cusom internal bits such as P4_CONFIG_HT,
* This allow us to relax restrictions a bit and run two or more
* identical events together.
*
* Never set any custom internal bits such as P4_CONFIG_HT,
* P4_CONFIG_ALIASABLE or bits for P4_PEBS_METRIC, they are
* either up-to-dated automatically either not appliable
* at all.
*
* And be really carefull choosing aliases!
* either up to date automatically or not applicable at all.
*/
struct p4_event_alias {
u64 orig;
u64 alter;
u64 original;
u64 alternative;
} p4_event_aliases[] = {
{
/*
* Non-halted cycles can be substituted with
* non-sleeping cycles (see Intel SDM Vol3b for
* details).
* Non-halted cycles can be substituted with non-sleeping cycles (see
* Intel SDM Vol3b for details). We need this alias to be able
* to run nmi-watchdog and 'perf top' (or any other user space tool
* which is interested in running PERF_COUNT_HW_CPU_CYCLES)
* simultaneously.
*/
.orig =
.original =
p4_config_pack_escr(P4_ESCR_EVENT(P4_EVENT_GLOBAL_POWER_EVENTS) |
P4_ESCR_EMASK_BIT(P4_EVENT_GLOBAL_POWER_EVENTS, RUNNING)),
.alter =
.alternative =
p4_config_pack_escr(P4_ESCR_EVENT(P4_EVENT_EXECUTION_EVENT) |
P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, NBOGUS0)|
P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, NBOGUS1)|
@ -620,25 +619,21 @@ static u64 p4_get_alias_event(u64 config)
int i;
/*
* Probably we're lucky and don't have to do
* matching over all config bits.
* Only event with special mark is allowed,
* we're to be sure it didn't come as malformed
* RAW event.
*/
if (!(config & P4_CONFIG_ALIASABLE))
return 0;
config_match = config & P4_CONFIG_EVENT_ALIAS_MASK;
/*
* If an event was previously swapped to the alter config
* we should swap it back otherwise contnention on registers
* will return back.
*/
for (i = 0; i < ARRAY_SIZE(p4_event_aliases); i++) {
if (config_match == p4_event_aliases[i].orig) {
config_match = p4_event_aliases[i].alter;
if (config_match == p4_event_aliases[i].original) {
config_match = p4_event_aliases[i].alternative;
break;
} else if (config_match == p4_event_aliases[i].alter) {
config_match = p4_event_aliases[i].orig;
} else if (config_match == p4_event_aliases[i].alternative) {
config_match = p4_event_aliases[i].original;
break;
}
}
@ -646,8 +641,7 @@ static u64 p4_get_alias_event(u64 config)
if (i >= ARRAY_SIZE(p4_event_aliases))
return 0;
return config_match |
(config & P4_CONFIG_EVENT_ALIAS_IMMUTABLE_BITS);
return config_match | (config & P4_CONFIG_EVENT_ALIAS_IMMUTABLE_BITS);
}
static u64 p4_general_events[PERF_COUNT_HW_MAX] = {
@ -1229,9 +1223,9 @@ static int p4_pmu_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign
again:
/*
* Aliases are swappable so we may hit circular
* lock if both original config and alias need
* resources (MSR registers) which already busy.
* It's possible to hit a circular lock
* between original and alternative events
* if both are scheduled already.
*/
if (pass > 2)
goto done;
@ -1251,7 +1245,7 @@ again:
cntr_idx = p4_next_cntr(thread, used_mask, bind);
if (cntr_idx == -1 || test_bit(escr_idx, escr_mask)) {
/*
* Probably an event alias is still available.
* Check whether an event alias is still available.
*/
config_alias = p4_get_alias_event(hwc->config);
if (!config_alias)