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 A2751EB64D9 for ; Wed, 14 Jun 2023 09:28:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244045AbjFNJ2N (ORCPT ); Wed, 14 Jun 2023 05:28:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244015AbjFNJ16 (ORCPT ); Wed, 14 Jun 2023 05:27:58 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A9E82101 for ; Wed, 14 Jun 2023 02:27:48 -0700 (PDT) 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=VDebGFAjszJ5XxlaZqcuzZVx+4xABvp4FBCOBoh0wpk=; b=oVFOIK4NIs1FPvKm+/aEHyFM+j cRPcx5dQiV0T+ATXpvKSOXcsGC+nbTxY4G8QZSOD6bcRDCWS8zAPo0MiwUVf0pMMh6wIfrs+GIYEU dDJDfygNp1+D25051m/UJiAQyZioxKtuBBJx6xZBolTA+x1gnlB0s73TAx9kJUC/LMuqOk7qOi0s1 udvv48BeWmxmmFz0Aeuc4eBF80p2PHMm8O+1riUcARsspO0/pkXey7HyRfbEdgJWdOvSob66mXqL4 WdCusxBjVjpZkydMkpb0qgg5wDKGlajsHh5agAZp3lCK2FRS3UetZSnyq2zdYjyjz53Cvhk3/a5I9 s4uiLljg==; 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 1q9MmT-00AfgI-1t; Wed, 14 Jun 2023 09:27:10 +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)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AB4F7300195; Wed, 14 Jun 2023 11:27:07 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 64B672C676971; Wed, 14 Jun 2023 11:27:07 +0200 (CEST) Date: Wed, 14 Jun 2023 11:27:07 +0200 From: Peter Zijlstra To: Aaron Lu Cc: David Vernet , linux-kernel@vger.kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, joshdon@google.com, roman.gushchin@linux.dev, tj@kernel.org, kernel-team@meta.com Subject: Re: [RFC PATCH 3/3] sched: Implement shared wakequeue in CFS Message-ID: <20230614092707.GG1639749@hirez.programming.kicks-ass.net> References: <20230613052004.2836135-1-void@manifault.com> <20230613052004.2836135-4-void@manifault.com> <20230613083203.GR4253@hirez.programming.kicks-ass.net> <20230614043529.GA1942@ziqianlu-dell> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230614043529.GA1942@ziqianlu-dell> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 14, 2023 at 12:35:29PM +0800, Aaron Lu wrote: > On Tue, Jun 13, 2023 at 10:32:03AM +0200, Peter Zijlstra wrote: > > > > Still gotta read it properly, however: > > > > On Tue, Jun 13, 2023 at 12:20:04AM -0500, David Vernet wrote: > > > Single-socket | 32-core | 2-CCX | AMD 7950X Zen4 > > > Single-socket | 72-core | 6-CCX | AMD Milan Zen3 > > > Single-socket | 176-core | 11-CCX | 2-CCX per CCD | AMD Bergamo Zen4c > > > > Could you please also benchmark on something Intel that has these stupid > > large LLCs ? > > > > Because the last time I tried something like this, it came apart real > > quick. And AMD has these relatively small 8-core LLCs. > > I tested on Intel(R) Xeon(R) Platinum 8358, which has 2 sockets and each > socket has a single LLC with 32 cores/64threads. > The lock contention due to the per-LLC swqueue->lock is quite serious: Yep, that's what I was expecting -- complete meltdown that.