From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 4ABF920F8 for ; Sun, 26 Mar 2023 13:39:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RjRNfqSt/cZcdh2NlAVQZwyjFXasWigZvmeJpOPbLg0=; b=SKslSt4ARXe4rPkahfBqUw5DWo +n9Zo9pnI0cwbcrWrgIxUNXVEtOyeyF/oeUv5e3Ylx1CWOD/X4X3lR9LPEptwT64cCeIkJt2i43z/ eQW+z0Ogg03shniHpCW/DTZ4+4OgUpA049lE75IYMpwQfUy63z6ynpWnGtB26MWi86OHeb70PVFwg hcBhATwYcc8pUqIKTzuFg0YN9L0/5Yo60Zy7RIWq2aW+jMU3uGDIB95x+HodAyRxuv5lCgLDzY22W uxDLOepvRkHmifsp9Y58kwpSqdgmTGpfsuxRyk5wSPgA0VBZfem7BenZmkELRpXJL8DraWSveAzxd DGjwlU8w==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pgQaC-005q5h-2t; Sun, 26 Mar 2023 13:38:53 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 581A13001E5; Sun, 26 Mar 2023 15:38:51 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3AF25240FBBBC; Sun, 26 Mar 2023 15:38:51 +0200 (CEST) Date: Sun, 26 Mar 2023 15:38:51 +0200 From: Peter Zijlstra To: Chen Yu Cc: oe-lkp@lists.linux.dev, lkp@intel.com, Oliver Sang , Chen Yu , Ingo Molnar Subject: Re: [peterz-queue:sched/eevdf] [sched/fair] 23669fce72: aim7.jobs-per-min -18.6% regression Message-ID: <20230326133851.GA2994912@hirez.programming.kicks-ass.net> References: <202303201517.399a9b16-oliver.sang@intel.com> <20230320075850.GA2194297@hirez.programming.kicks-ass.net> <20230321090318.GB2234901@hirez.programming.kicks-ass.net> <20230326110024.GA2990748@hirez.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: oe-lkp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230326110024.GA2990748@hirez.programming.kicks-ass.net> On Sun, Mar 26, 2023 at 01:00:24PM +0200, Peter Zijlstra wrote: > sched/eevdf + place_bonus (based on tip/sched/urgent -- will push out > later today) > > root@ivb-ep:~# echo NO_PLACE_BONUS > /debug/sched/features ; stress-ng --futex 40 -t 5 --metrics 2>&1 | awk '{ if ($4 == "futex") print $0 }' > stress-ng: info: [2373] futex 6541589 5.00 4.28 194.83 1308211.07 32854.97 99.54 2288 > root@ivb-ep:~# echo PLACE_BONUS > /debug/sched/features ; stress-ng --futex 40 -t 5 --metrics 2>&1 | awk '{ if ($4 == "futex") print $0 }' > stress-ng: info: [2537] futex 9745715 5.00 5.38 194.55 1948945.01 48745.49 99.96 2288 > > > The whole sleeper bonus is something that's fairly controversial but it > was needed in CFS to make some 'starvation' cases go away -- the lag > based placement cures them too. And given the whole (recent) trainwreck with: > > 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") > a53ce18cacb4 ("sched/fair: Sanitize vruntime of entity being migrated") > > I'm happy to delete all that. Still, let me think a little, perhaps I > can come up with something slightly less horrible than all that which we > can default-disable for now... OK, pushed a new version of sched/eevdf that includes a default disabled PLACE_BONUS. (and lots of other cleanups, eg. moved to scale_load_down() for avg_vruntime and measured the max delta to be ~44 bits for a systemd/cgroup using kernel build -- after I fixed a cgroup placement issue).