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 X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 260F1ECDE5F for ; Thu, 19 Jul 2018 09:26:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBCE820856 for ; Thu, 19 Jul 2018 09:26:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="2UrTct1T" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBCE820856 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727556AbeGSKIr (ORCPT ); Thu, 19 Jul 2018 06:08:47 -0400 Received: from merlin.infradead.org ([205.233.59.134]:33382 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727441AbeGSKIr (ORCPT ); Thu, 19 Jul 2018 06:08:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; 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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=/XzYF6OgunbOCgX1qSMgWlG2svJbh/a+gYsM8px3vOQ=; b=2UrTct1TTh99ANKw7NpiSZmc+ 0NZS3UQ6cBIcbHNb4sN2U+yetfGdkVYM0uRe9VyDSKvu+927ANZXnZBiX/GXDa04DwqA2tqTRncD/ xdHZzyQEwEYW/DUCzBD7mf1mAJXwp1szVCkqCLUg6tHzhv++zvnmjWxYOmpXUroolyDMtQg4+oinU iLLnhysu4TV6jUByFlkrOYUbE/lsL9VbH1f7BQOYcRGy+75PWgQI+DAeMQsKZbOUqwZBCdShBagdy LqMslZdDXEK1K+/QaB3kq1Quhtnt7uOQeZ7yWYM8PGxK/wVNZrqxvAP6gKUzex5zLwSqgIZPGio6S 6badXPe3g==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fg5CR-00023M-Jm; Thu, 19 Jul 2018 09:26:15 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5E7BD20289330; Thu, 19 Jul 2018 11:26:14 +0200 (CEST) Date: Thu, 19 Jul 2018 11:26:14 +0200 From: Peter Zijlstra To: Johannes Weiner Cc: Ingo Molnar , Andrew Morton , Linus Torvalds , Tejun Heo , Suren Baghdasaryan , Vinayak Menon , Christopher Lameter , Mike Galbraith , Shakeel Butt , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 08/10] psi: pressure stall information for CPU, memory, and IO Message-ID: <20180719092614.GY2512@hirez.programming.kicks-ass.net> References: <20180712172942.10094-1-hannes@cmpxchg.org> <20180712172942.10094-9-hannes@cmpxchg.org> <20180718120318.GC2476@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180718120318.GC2476@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 18, 2018 at 02:03:18PM +0200, Peter Zijlstra wrote: > Leaving us just 5 bytes short of needing a single cacheline :/ > > struct ponies { > unsigned int tasks[3]; /* 0 12 */ > unsigned int cpu_state:2; /* 12:30 4 */ > unsigned int io_state:2; /* 12:28 4 */ > unsigned int mem_state:2; /* 12:26 4 */ > > /* XXX 26 bits hole, try to pack */ > > /* typedef u64 */ long long unsigned int last_time; /* 16 8 */ > /* typedef u64 */ long long unsigned int some_time[3]; /* 24 24 */ > /* typedef u64 */ long long unsigned int full_time[2]; /* 48 16 */ > /* --- cacheline 1 boundary (64 bytes) --- */ > /* typedef u64 */ long long unsigned int nonidle_time; /* 64 8 */ > > /* size: 72, cachelines: 2, members: 8 */ > /* bit holes: 1, sum bit holes: 26 bits */ > /* last cacheline: 8 bytes */ > }; > > ARGGH! It _might_ be possible to use curr->se.exec_start for last_time if you very carefully audit and place the hooks. I've not gone through it in detail, but it might just work.