From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D2165810F for ; Thu, 11 Jan 2024 20:43:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oPc4/CVB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B87E1C433A6; Thu, 11 Jan 2024 20:43:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705005830; bh=A4VhAo2thc3VPIG5HMtbRNaNrF0RwGaTT512LSk8+14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oPc4/CVBLd0WDTsE0CfRKBMLzKaJeYqEHgLAuo4IPCFvh2RmzP4+fv2iLEsKFJC2X ytStGdLBRCGiYpoeIvv6NEr98BoxG3yXGNAoS6TTFIqmLhhwy53zgp2wBUTRxiAsjP bgpqdpDzaeZk6rHBh+vqJsrINIaTU4mBzTZlYCaEoIrH02qIdZ8nSXFsWgaYla1vl0 cWb2wCdeaq4nrhRdV2rDB3Dqb3TdhGgr7lLu1KK8+cM3by12769l2pmuSJfb4YwfMT wsn6G07+eRM4zMStXioTAeguASBOxljBw+HoIMY4r6JwRt0X/aadSAoUBF3c/atWC5 /IOlL39X2X4uw== From: namhyung@kernel.org To: Peter Zijlstra , Ingo Molnar Cc: Mark Rutland , Alexander Shishkin , Arnaldo Carvalho de Melo , LKML , Mingwei Zhang , Namhyung Kim , Ian Rogers , Kan Liang Subject: [PATCH v2 2/2] perf/core: Reduce PMU access to adjust sample freq Date: Thu, 11 Jan 2024 12:43:48 -0800 Message-ID: <20240111204348.669673-2-namhyung@kernel.org> X-Mailer: git-send-email 2.43.0.275.g3460e3d667-goog In-Reply-To: <20240111204348.669673-1-namhyung@kernel.org> References: <20240111204348.669673-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Namhyung Kim For throttled events, it first starts the event and then stop unnecessarily. As it's already stopped, it can directly adjust the frequency and then move on. Reviewed-by: Ian Rogers Reviewed-by: Kan Liang Signed-off-by: Namhyung Kim --- kernel/events/core.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index e9ce79c8c145..243cd09ba7fe 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4121,10 +4121,15 @@ static void perf_adjust_freq_unthr_events(struct list_head *event_list) if (hwc->interrupts == MAX_INTERRUPTS) { hwc->interrupts = 0; perf_log_throttle(event, 1); - event->pmu->start(event, 0); - } - if (!event->attr.freq || !event->attr.sample_freq) + if (!event->attr.freq || !event->attr.sample_freq) { + delta = 0; + goto next; + } + + if (event->hw.state & PERF_HES_STOPPED) + goto adjust; + } else if (!event->attr.freq || !event->attr.sample_freq) continue; /* @@ -4132,6 +4137,7 @@ static void perf_adjust_freq_unthr_events(struct list_head *event_list) */ event->pmu->stop(event, PERF_EF_UPDATE); +adjust: now = local64_read(&event->count); delta = now - hwc->freq_count_stamp; hwc->freq_count_stamp = now; @@ -4146,6 +4152,7 @@ static void perf_adjust_freq_unthr_events(struct list_head *event_list) if (delta > 0) perf_adjust_period(event, period, delta, false); +next: event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); } } -- 2.43.0.275.g3460e3d667-goog