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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,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 0656FC43387 for ; Wed, 9 Jan 2019 18:24:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C737C214C6 for ; Wed, 9 Jan 2019 18:24:25 +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="FTTWKA3b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726963AbfAISYV (ORCPT ); Wed, 9 Jan 2019 13:24:21 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:36938 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726221AbfAISYU (ORCPT ); Wed, 9 Jan 2019 13:24:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=hl/E6OTbfUDCWrNXtNrojAg8mlkKgNjYPdSbJh0+gIo=; b=FTTWKA3bMyxzdygMiOVXhisnS SkPefX3UrEzfC1qjoSCawywq9vIE1LFOLCXXw4bXGKMtqdqI7vX/TAZh7g9us9xlXpZMLRK1tjRfD v0lKqwtYVNLNxJaQhSUUhG41orxQ9T8dyJerTSUCVjxrrEoQezVbkY1va5eEeC+EhRIci1/TavSrk vwS8TOTULqeK1mNqjWjWiNTpw6z1hcMuJKkgceBJ1HhCIwpbm3rejn7ezN6BNN7AAm0KOLhfh7DP6 Mkd64hMoEUotAj6KhMEyDYXbiuV9Cyc0XA7XYfkk3ar/VUAlkcZLWMu2+BxvXzt0ebQ/xbX29kLVT hgE+SDKSA==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghIWY-0006H6-4x; Wed, 09 Jan 2019 18:24:18 +0000 Date: Wed, 9 Jan 2019 10:24:17 -0800 From: Matthew Wilcox To: Waiman Long Cc: Andrew Morton , Alexey Dobriyan , Kees Cook , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Davidlohr Bueso , Miklos Szeredi , Daniel Colascione , Dave Chinner , Randy Dunlap Subject: Re: [PATCH v2 0/4] /proc/stat: Reduce irqs counting performance overhead Message-ID: <20190109182417.GO6310@bombadil.infradead.org> References: <1547054628-12703-1-git-send-email-longman@redhat.com> <20190109174403.GN6310@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 09, 2019 at 01:03:33PM -0500, Waiman Long wrote: > The paragraph above may be a bit misleading. This v2 patch actually > touches very little on percpu accounting aspect of the IRQ counts. See > patches 2 and 3 for the relevant changes which is just a few line of new > codes. Please review the individual patches before Nak'ing. > > I could theoretically generalize them into a new set of percpu counting > helpers, but the idea behind it is quite different from the use cases of > percpu counter. So it may not be a good idea of adding it to there. Did you even try just using the general purpose infrastructure that's in place? If that shows a performance problem _then_ it's time to make this special snowflake just a little more special. Not before.