From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, eranian@google.com, jolsa@redhat.com
Cc: linux-kernel@vger.kernel.org, tonyj@suse.com,
nelson.dsouza@intel.com, peterz@infradead.org
Subject: [RFC][PATCH 5/8] perf/x86/intel: Optimize intel_get_excl_constraints()
Date: Thu, 14 Mar 2019 14:01:18 +0100 [thread overview]
Message-ID: <20190314130705.852659665@infradead.org> (raw)
In-Reply-To: 20190314130113.919278615@infradead.org
Avoid the POPCNT by noting we can decrement the weight for each
cleared bit.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/events/intel/core.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2838,7 +2838,7 @@ intel_get_excl_constraints(struct cpu_hw
struct intel_excl_cntrs *excl_cntrs = cpuc->excl_cntrs;
struct intel_excl_states *xlo;
int tid = cpuc->excl_thread_id;
- int is_excl, i;
+ int is_excl, i, w;
/*
* validating a group does not require
@@ -2894,36 +2894,40 @@ intel_get_excl_constraints(struct cpu_hw
* SHARED : sibling counter measuring non-exclusive event
* UNUSED : sibling counter unused
*/
+ w = c->weight;
for_each_set_bit(i, c->idxmsk, X86_PMC_IDX_MAX) {
/*
* exclusive event in sibling counter
* our corresponding counter cannot be used
* regardless of our event
*/
- if (xlo->state[i] == INTEL_EXCL_EXCLUSIVE)
+ if (xlo->state[i] == INTEL_EXCL_EXCLUSIVE) {
__clear_bit(i, c->idxmsk);
+ w--;
+ continue;
+ }
/*
* if measuring an exclusive event, sibling
* measuring non-exclusive, then counter cannot
* be used
*/
- if (is_excl && xlo->state[i] == INTEL_EXCL_SHARED)
+ if (is_excl && xlo->state[i] == INTEL_EXCL_SHARED) {
__clear_bit(i, c->idxmsk);
+ w--;
+ continue;
+ }
}
/*
- * recompute actual bit weight for scheduling algorithm
- */
- c->weight = hweight64(c->idxmsk64);
-
- /*
* if we return an empty mask, then switch
* back to static empty constraint to avoid
* the cost of freeing later on
*/
- if (c->weight == 0)
+ if (!w)
c = &emptyconstraint;
+ c->weight = w;
+
return c;
}
next prev parent reply other threads:[~2019-03-14 13:11 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-14 13:01 [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Peter Zijlstra
2019-03-14 13:01 ` [PATCH 1/8] perf/x86/intel: Fix memory corruption Peter Zijlstra
2019-03-15 11:29 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2019-03-19 6:29 ` [PATCH 1/8] " Stephane Eranian
2019-03-19 11:05 ` Peter Zijlstra
2019-03-19 17:52 ` Stephane Eranian
2019-03-19 18:20 ` Peter Zijlstra
2019-03-20 20:47 ` Stephane Eranian
2019-03-20 20:52 ` Stephane Eranian
2019-03-20 22:22 ` Peter Zijlstra
2019-03-21 12:38 ` Peter Zijlstra
2019-03-21 16:45 ` Thomas Gleixner
2019-03-21 17:10 ` Peter Zijlstra
2019-03-21 17:17 ` Thomas Gleixner
2019-03-21 18:20 ` Peter Zijlstra
2019-03-21 19:42 ` Tony Jones
2019-03-21 19:47 ` DSouza, Nelson
2019-03-21 20:07 ` Peter Zijlstra
2019-03-21 23:16 ` DSouza, Nelson
2019-03-22 22:14 ` DSouza, Nelson
2019-03-21 17:23 ` Stephane Eranian
2019-03-21 17:51 ` Thomas Gleixner
2019-03-22 19:04 ` Stephane Eranian
2019-04-03 7:32 ` Peter Zijlstra
2019-04-03 10:40 ` [tip:perf/urgent] perf/x86/intel: Initialize TFA MSR tip-bot for Peter Zijlstra
2019-04-03 11:30 ` Thomas Gleixner
2019-04-03 12:23 ` Vince Weaver
2019-03-14 13:01 ` [RFC][PATCH 2/8] perf/x86/intel: Simplify intel_tfa_commit_scheduling() Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 3/8] perf/x86: Simplify x86_pmu.get_constraints() interface Peter Zijlstra
2019-03-19 21:21 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT_COMMITTED Peter Zijlstra
2019-03-19 20:48 ` Stephane Eranian
2019-03-19 21:00 ` Peter Zijlstra
2019-03-20 13:14 ` Peter Zijlstra
2019-03-20 12:23 ` Peter Zijlstra
2019-03-14 13:01 ` Peter Zijlstra [this message]
2019-03-19 23:43 ` [RFC][PATCH 5/8] perf/x86/intel: Optimize intel_get_excl_constraints() Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 6/8] perf/x86: Clear ->event_constraint[] on put Peter Zijlstra
2019-03-19 21:50 ` Stephane Eranian
2019-03-20 12:25 ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 7/8] perf/x86: Optimize x86_schedule_events() Peter Zijlstra
2019-03-19 23:55 ` Stephane Eranian
2019-03-20 13:11 ` Peter Zijlstra
2019-03-20 19:30 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 8/8] perf/x86: Add sanity checks to x86_schedule_events() Peter Zijlstra
2019-03-15 7:15 ` [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Stephane Eranian
2019-03-15 7:15 ` Stephane Eranian
2019-03-15 8:01 ` Peter Zijlstra
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