From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-184.mta1.migadu.com (out-184.mta1.migadu.com [95.215.58.184]) (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 A60A54A08 for ; Thu, 13 Feb 2025 02:57:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739415455; cv=none; b=fGYx2cnHf3CKgmcoAzgvAE+zR7CbYPOp7al8i31EEF7tTw6r55ml6NR7BqsKIDfEVKYTyShvYDE1GAunMhkAyZ0eC9s0IX+e/RfTrwNAYAO5J1stIykmIyilCM1qBQn4nTxwU0RgbmW47n2oaUIdIUnIddOa4qjbhzGoakXANZY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739415455; c=relaxed/simple; bh=CpcRkamTjzxXr7oWqpFy5FD2Fuz+fACZLhbK+eoL7wA=; h=MIME-Version:Date:Content-Type:From:Message-ID:Subject:To:Cc: In-Reply-To:References; b=W5k0Xx4G9vrMtzT+Ur2rh9pwNj0S67U66XXGW2ehuSYXoJ6ByYwlPIJc8HVApW8SlGpX/LIeXV2UkRD8llqM3fV74OvCbHeGSIkMOUFkvySxBVLgn9jCHzXMGFJ95/+90EC0piXT2kki5AXcnsdbrg357matIoKaVmAIdLNMMog= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=u1drbhpy; arc=none smtp.client-ip=95.215.58.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="u1drbhpy" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1739415450; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NmWV5qLBGFJ380Q636JbOBAatzAC28wVNjP4Bc1s1jY=; b=u1drbhpyXca+ZGXrN2eKhW797pCKeYFtckSmOgpaly4XqfrUi0RKF0Zi8FCQpWkVWcqLRG wOdHIVDU29LKTCRpasCW+6ns0+bLvOaOi7ssmTz9Aax8GpIqgTGkswExqdQMYk8dCeCo42 HxSa1vj8ZjeGQdz/cjFa6wCr/yF6J0o= Date: Thu, 13 Feb 2025 02:57:28 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Yosry Ahmed" Message-ID: <25268fbedb82a06ba0c13e2c490b164846ef508b@linux.dev> TLS-Required: No Subject: Re: [PATCHv4 14/17] zsmalloc: make zspage lock preemptible To: "Sergey Senozhatsky" Cc: "Sergey Senozhatsky" , "Andrew Morton" , "Minchan Kim" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kairui Song" In-Reply-To: References: <6vtpamir4bvn3snlj36tfmnmpcbd6ks6m3sdn7ewmoles7jhau@nbezqbnoukzv> <6uhsj4bckhursiblkxe54azfgyqal6tq2de3lpkxw6omkised6@uylodcjruuei> X-Migadu-Flow: FLOW_OUT February 12, 2025 at 6:18 PM, "Sergey Senozhatsky" wrote: >=20 >=20On (25/02/12 15:35), Yosry Ahmed wrote: >=20 >=20>=20 >=20> Difference at 95.0% confidence > >=20 >=20> -1.03219e+08 +/- 55308.7 > >=20 >=20> -27.9705% +/- 0.0149878% > >=20 >=20> (Student's t, pooled s =3D 58864.4) > >=20 >=20>=20=20 >=20>=20 >=20> Thanks for sharing these results, but I wonder if this will captur= e > >=20 >=20> regressions from locking changes (e.g. a lock being preemtible)? I= IUC > >=20 >=20> this is counting the instructions executed in these paths, and tha= t > >=20 >=20> won't change if the task gets preempted. Lock contention may be ca= ptured > >=20 >=20> as extra instructions, but I am not sure we'll directly see its ef= fect > >=20 >=20> in terms of serialization and delays. > >=20 >=20 > Yeah.. >=20 >=20>=20 >=20> I think we also need some high level testing (e.g. concurrent > >=20 >=20> swapins/swapouts) to find that out. I think that's what Kairui's t= esting > >=20 >=20> covers. > >=20 >=20 > I do a fair amount of high-level testing: heavy parallel (make -j36 and >=20 >=20parallel dd) workloads (multiple zram devices configuration - zram0 e= xt4, >=20 >=20zram1 writeback device, zram2 swap) w/ and w/o lockdep. In addition I= also >=20 >=20run these workloads under heavy memory pressure (a 4GB VM), when oom-= killer >=20 >=20starts to run around with a pair of scissors. But it's mostly regress= ion >=20 >=20testing. > If we can get some numbers from these parallel workloads that would be be= tter than the perf stats imo.