From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0526AC433FE for ; Wed, 2 Nov 2022 17:11:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231296AbiKBRLK (ORCPT ); Wed, 2 Nov 2022 13:11:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231143AbiKBRKx (ORCPT ); Wed, 2 Nov 2022 13:10:53 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 281F41CB1C for ; Wed, 2 Nov 2022 10:10:52 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id D2F7921D91; Wed, 2 Nov 2022 17:10:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1667409050; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CN7rpKi1JV2qkEsMCHV68X0g7v+Lhbb9nJKm2oiwPZU=; b=mAQp1ZgQJP0vX2tskn5KkVkJOI670pTg2w8TneMpJRXk8RExrcPyoSo+KGEFf1FcdmETE/ iVExAu+9vD44Rfo6/z2wnOzsXrUFPjqpjPG4u+jqHvz2okPQfidpFwDNBFz10cukhrlzQR CMGQZp4gum5CS/Cm3JqrEcLCwGdTouw= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 83D7113AE0; Wed, 2 Nov 2022 17:10:50 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id +vY3H5qkYmN1OAAAMHmgww (envelope-from ); Wed, 02 Nov 2022 17:10:50 +0000 Date: Wed, 2 Nov 2022 18:10:49 +0100 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Tejun Heo Cc: Josh Don , Peter Zijlstra , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , linux-kernel@vger.kernel.org, Joel Fernandes , Christian Brauner , Zefan Li Subject: Re: [PATCH v2] sched: async unthrottling for cfs bandwidth Message-ID: <20221102171049.GC10591@blackbody.suse.cz> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="QRj9sO5tAVLaXnSD" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --QRj9sO5tAVLaXnSD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Nov 01, 2022 at 12:38:23PM -1000, Tejun Heo wrote: > (cc'ing Michal, Christian and Li for context) Thanks. > > We're in the process of transitioning to using bw instead for this > > instead in order to maintain parallelism. Fixing bw is definitely > > going to be useful, but I'm afraid we'll still likely have some issues > > from low throughput for non-bw reasons (some of which we can't > > directly control, since arbitrary jobs can spin up and configure their > > hierarchy/threads in antagonistic ways, in effect pushing out the > > latency of some of their threads). >=20 > Yeah, thanks for the explanation. Making the lock more granular is tedious > but definitely doable. I don't think I can work on it in the near future = but > will keep it on mind. If anyone's interested in attacking it, please be my > guest. =46rom my experience, throttling while holding kernel locks (not just cgroup_mutex) causes more trouble than plain cgroup_mutex scalability currently. But I acknowledge the latter issue too. Michal --QRj9sO5tAVLaXnSD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iHUEARYIAB0WIQTrXXag4J0QvXXBmkMkDQmsBEOquQUCY2KklwAKCRAkDQmsBEOq uZ9JAP4z/W1MGdhX6ZkuGKjgkWAmGksEpsGwm6hcT3ngQNH4PgEAm4jQZq/iaK4d P42yKxWJy4D0SNDA9w+Dx+N0GFXf6ww= =aZnM -----END PGP SIGNATURE----- --QRj9sO5tAVLaXnSD--