From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 0CCFC410D24 for ; Mon, 10 Aug 2026 15:02:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786374164; cv=none; b=T5gBNFeup89AtcDNrtsZfAY4yLhBL7UkaA3d6NpCwz9BNP1md3DFatNSRy6ZSaEUTDevvdWYzkPVw1qq0Im9ufzEKAvxySYmJ1ip3RBDsiyKIEEM9NgUAFtTfet13Z+rt3UrFt+fbE3enV5PcOJ6sc+3IkqxxHge1gH2pT/tJWE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786374164; c=relaxed/simple; bh=tPk72QStPjoickmYuIutJ9AA2N0tV5W3b9J9+EArYm0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Sldx2NDodLfKLt+vr5WlN7+A73KXoyqV3Nf0tdjUHqGNG00IqLp6Hm6uXs0GaOj4gN4MvqWv5f2zn9Zaz063jYJVQLoASX4oVzaN9OBoe+EOBtkl/yk39VblGyz+OZLIFfaccVeyWZfZ/+r49E8+xDGWe14o+Hi95OiNgZpkdiE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=L6cjxrNJ; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="L6cjxrNJ" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 67AD1bZe600232; Mon, 10 Aug 2026 15:02:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=redZMT hDwiwek5xBRSC9cg066fYYUvl87iZlJJhAXmY=; b=L6cjxrNJz3xURaOBwl48oY yy95ppIkjPwL8KPCdrHFEdlkGad6Xemf8KC7zLjBW4XIsWAEN7Wh+flM35CL+SeH 16N4ySmLSffm1hvxTVKuhKgtJim64sYNMEtvkYUprRNA1xM83yExsqRN/4wur6EH EBVz/1XeDltzkSiwRnt5rPftf3yj5dRZ7gLtHYOsNjqJTxDGXWDINEQsrKHeL21w KZDPHsc/+3UtMXcqH95oxxEwGaqYKu7hoxZKiHT98mZvUXQFIYfEazxFh+cNGGhw eSdTmnrdzune3i0K1DparGp7qG/6jIAPIKVORUOsc0SSYfca4Yywl6qQQrSpK3Rw == Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fyb23hhwm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 10 Aug 2026 15:02:04 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 67AEuJa1026032; Mon, 10 Aug 2026 15:02:03 GMT Received: from smtprelay02.dal12v.mail.ibm.com ([172.16.1.4]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4fxg9gw6hy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 10 Aug 2026 15:02:03 +0000 (GMT) Received: from smtpav05.wdc07v.mail.ibm.com (smtpav05.wdc07v.mail.ibm.com [10.39.53.232]) by smtprelay02.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 67AF22m961604310 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 10 Aug 2026 15:02:03 GMT Received: from smtpav05.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AD3E358059; Mon, 10 Aug 2026 15:02:02 +0000 (GMT) Received: from smtpav05.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4542658053; Mon, 10 Aug 2026 15:01:56 +0000 (GMT) Received: from [9.43.80.244] (unknown [9.43.80.244]) by smtpav05.wdc07v.mail.ibm.com (Postfix) with ESMTP; Mon, 10 Aug 2026 15:01:55 +0000 (GMT) Message-ID: Date: Mon, 10 Aug 2026 20:31:54 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] sched/fair: Let sync wakeups target the waker's core To: Kayra Cizmeci Cc: bsegall@google.com, dietmar.eggemann@arm.com, juri.lelli@redhat.com, kprateek.nayak@amd.com, linux-kernel@vger.kernel.org, mgorman@suse.de, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, sh@gentwo.org, vincent.guittot@linaro.org, vschneid@redhat.com, Madadi Vineeth Reddy References: <20260801035532.260625-1-vineethr@linux.ibm.com> <20260806130326.79538-1-kayracizmeci@gmail.com> Content-Language: en-US From: Madadi Vineeth Reddy In-Reply-To: <20260806130326.79538-1-kayracizmeci@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=XqfK/1F9 c=1 sm=1 tr=0 ts=6a79e7ec cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=pGLkceISAAAA:8 a=yElQXcdgO0zNSMveLEIA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEwMDEyOSBTYWx0ZWRfX8ACfVnzkQ00/ GgT5/E+enLnLr8TjMnmmVn8/DSjl2LescLPNSDjfjJjagjQ6rYKLyq02DP5AbNiRpUMYXdNTjE5 ZK7YbqMGkZ2FMQwCbgqm9IWFeltEeFyzC4aHUW0X5MNKnjCYUtQQ8Ejg6NqcS+jCFmto3VTpAEH hWt/wynu2neAlTCJYwy4dDb8uLqPXK9RYUIFbvVfr932H7IHdo3LVcYy6QWxo8j+AgM+7UjSfkr NcGQknSVsRIK4LSVe8e48PTGpfGGiEZTInWpVuBH9E3DD1bIELAINCnXF4jRPxpZfxNNHTER/eq ah3/mhEMHNMkldypvO7n1RiLSarC7xsFD5PgS7jJ3qRCe10gKIvS4wJt1ygA3hgWsuPf5o+RW4I dZi4G4F9M3pBHM3rr2GMgj0sVD54RpVPsWcN2f/mC6Z6DyB8ZQKA4OzByrZvEQAm60+Mkej22F8 5ajJHv77dtqJFWHq+Rg== X-Proofpoint-ORIG-GUID: KJceXrt_eZ0UPFxagosHYexd7wkuaffn X-Proofpoint-GUID: PjIHLXGzv6VRUSprCfvw9K1l5YrRnV2v X-Proofpoint-Spam-Info: AW1haW4tMjYwODEwMDEyOSBTYWx0ZWRfXxHEKqgnuDfma 3fAynJ4fi/i6n1APDZl0G+WjvLbLCAHKl8+BnIJ9HtgE6Rf+fovKsQu6kpnXpjMgMiZioGR0J0i 89+crT0HF67lUNOGCeVbZ8F7hAoah64= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-10_03,2026-08-07_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 spamscore=0 adultscore=0 malwarescore=0 clxscore=1015 suspectscore=0 priorityscore=1501 impostorscore=0 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608100129 Hi Kayra, On 06/08/26 18:33, Kayra Cizmeci wrote: > Hi Vineeth, > > Since all the numbers on this thread are from POWER, I ran this on x86 (Zen 3). I ran the test 3 times on both > baseline and baseline + patch. > Thank you for running this on x86 > I first got the baseline from 0d83957076 that was like that: > > =num===cycles===cache-misses= > [ 1: 11266587459: 19064897 ] > [ 2: 11329575367: 18860444 ] > [ 3: 11283159019: 19121436 ] > > Then, I got the 0d83957076 + this patch: > > =num===cycles===cache-misses= > [ 1: 11128721747: 19886131 ] > [ 2: 11163014797: 20019508 ] > [ 3: 11111832330: 19764849  ] Can you also provide the benchmark numbers so as to see if this patch helped or not? I would like to see whether the ping-pong throughput moved in the same direction as cycles. > > I tested them with AMD Ryzen 7 5700X 8 Cores, 16 Threads or by other means SMT2. Busybox, minimal initramfs and > perf or to be more specific, this command: perf stat -r 10 -e cycles,cache-misses perf bench sched pipe > > There is a 1.40% decrease of cycles baseline to this patch while there is a 4.60% increase in cache-misses. > Both of these values are average values of the decrease and the increase. The values also don't overlap. > > I don't really have explanations for why this values came back like that, > I wasn't expecting them to be like this. Especially cache-misses. It would help if you can get L1, L2, L3 misses split in both cases. May be L1/L2 misses are more but since they are cheaper than L3, we may be alright or wakeup is cheaper when it stays within a core, independently of any data-cache effect, in which case the two counters are measuring unrelated things -- scheduling got cheaper while the memory access pattern got worse. I do not have evidence for that yet, which is why I would like the benchmark numbers. > > Tested-by: Kayra Cizmeci Will respin another version based on suggestions from Prateek and in_task() gate that Chen Yu suggested. Let me know if I can carry forward this tag or drop it in v2. Thanks, Vineeth > > Thanks, > Kayra