From: David Carrillo-Cisneros <davidcc@google.com>
To: linux-kernel@vger.kernel.org
Cc: "x86@kernel.org" <x86@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andi Kleen <ak@linux.intel.com>, Kan Liang <kan.liang@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@suse.de>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Vikas Shivappa <vikas.shivappa@linux.intel.com>,
Mark Rutland <mark.rutland@arm.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Vince Weaver <vince@deater.net>, Paul Turner <pjt@google.com>,
Stephane Eranian <eranian@google.com>,
David Carrillo-Cisneros <davidcc@google.com>
Subject: [RFC 5/6] perf/core: rotation no longer necessary. Behavior has changed. Beware
Date: Tue, 10 Jan 2017 02:25:01 -0800 [thread overview]
Message-ID: <20170110102502.106187-6-davidcc@google.com> (raw)
In-Reply-To: <20170110102502.106187-1-davidcc@google.com>
The sched in/out process updates timestamps and "rotates"
ctx->inactive_groups.
This changes the speed at which rotation happens. Before events will
rotate one event per interruption, now they will rotate q events each
timer interruption. Where q is the number of events added to the pmu per
sched in.
Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
---
kernel/events/core.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c7715b2627a9..f5d9c13b485f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3642,19 +3642,6 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
raw_spin_unlock(&ctx->lock);
}
-/*
- * Round-robin a context's events:
- */
-static void rotate_ctx(struct perf_event_context *ctx)
-{
- /*
- * Rotate the first entry last of non-pinned groups. Rotation might be
- * disabled by the inheritance code.
- */
- if (!ctx->rotate_disable)
- list_rotate_left(&ctx->flexible_groups);
-}
-
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
{
struct perf_event_context *ctx = NULL;
@@ -3681,10 +3668,11 @@ static int perf_rotate_context(struct perf_cpu_context *cpuctx)
if (ctx)
ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
- rotate_ctx(&cpuctx->ctx);
- if (ctx)
- rotate_ctx(ctx);
-
+ /*
+ * A sched out will insert event groups at end of inactive_groups,
+ * a sched in will schedule events at the beginning of inactive_groups.
+ * This causes a rotation.
+ */
perf_event_sched_in(cpuctx, ctx, current);
perf_pmu_enable(cpuctx->ctx.pmu);
--
2.11.0.390.gc69c2f50cf-goog
next prev parent reply other threads:[~2017-01-10 10:26 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-10 10:24 [RFC 0/6] optimize ctx switch with rb-tree David Carrillo-Cisneros
2017-01-10 10:24 ` [RFC 1/6] perf/core: create active and inactive event groups David Carrillo-Cisneros
2017-01-10 13:49 ` Mark Rutland
2017-01-10 20:45 ` David Carrillo-Cisneros
2017-01-12 11:05 ` Mark Rutland
[not found] ` <CALcN6mhPmpSqKhE3Ua+j-xROLzeAyrgdCk4AGGtfF9kExXRTJg@mail.gmail.com>
2017-01-13 11:01 ` Mark Rutland
2017-01-10 10:24 ` [RFC 2/6] perf/core: add a rb-tree index to inactive_groups David Carrillo-Cisneros
2017-01-10 14:14 ` Mark Rutland
2017-01-10 20:20 ` David Carrillo-Cisneros
2017-01-12 11:47 ` Mark Rutland
2017-01-13 7:34 ` David Carrillo-Cisneros
2017-01-16 2:03 ` [lkp-developer] [perf/core] 33da94bd89: BUG:unable_to_handle_kernel kernel test robot
2017-01-10 10:24 ` [RFC 3/6] perf/core: use rb-tree to sched in event groups David Carrillo-Cisneros
2017-01-10 16:38 ` Mark Rutland
2017-01-10 20:51 ` David Carrillo-Cisneros
2017-01-12 12:14 ` Mark Rutland
2017-01-13 8:01 ` David Carrillo-Cisneros
2017-01-13 10:24 ` Mark Rutland
2017-01-11 20:31 ` Liang, Kan
2017-01-12 10:11 ` Mark Rutland
2017-01-12 13:28 ` Liang, Kan
2017-01-13 8:05 ` David Carrillo-Cisneros
2017-01-10 10:25 ` [RFC 4/6] perf/core: avoid rb-tree traversal when no inactive events David Carrillo-Cisneros
2017-01-10 10:25 ` David Carrillo-Cisneros [this message]
2017-01-10 10:25 ` [RFC 6/6] perf/core: use rb-tree index to optimize filtered perf_iterate_ctx David Carrillo-Cisneros
2017-01-16 2:05 ` [lkp-developer] [perf/core] 49c04ee1a7: WARNING:at_kernel/events/core.c:#perf_iterate_ctx_matching kernel test robot
2017-04-25 17:27 ` [RFC 0/6] optimize ctx switch with rb-tree Liang, Kan
2017-04-25 17:49 ` David Carrillo-Cisneros
2017-04-25 18:11 ` Budankov, Alexey
2017-04-25 18:54 ` David Carrillo-Cisneros
2017-04-26 10:34 ` Budankov, Alexey
2017-04-26 19:40 ` David Carrillo-Cisneros
2017-04-26 10:52 ` Mark Rutland
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