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_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 5B64DECDE30 for ; Wed, 17 Oct 2018 07:38:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 041BE214C3 for ; Wed, 17 Oct 2018 07:38:41 +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="HPMDze2U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 041BE214C3 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 S1727274AbeJQPdB (ORCPT ); Wed, 17 Oct 2018 11:33:01 -0400 Received: from merlin.infradead.org ([205.233.59.134]:41744 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727218AbeJQPdB (ORCPT ); Wed, 17 Oct 2018 11:33:01 -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=js9mWpExmwFkOZjKVC/ehWJNLHxvGgpbAznO3zQxpxk=; b=HPMDze2U9AI+SyFhNpEybi77z d9b39fBk13FdF4IyVxGNWTYzospS60QG/tRIGUHQmW4LrFs3txD+1TCeboESPfog4VMOhdKQu6Bdn GgXYo/r+P7xGzKdEmYqHcoYQxqvxd13vVgxbebdArK7qv7/Vj5WwecIVNoqmFw5W508UGQLQIbNNy AYCs0+Is92a2P3XzSvbygoeiwr0bMKQohJN43dG0HXusUnznZeZuXKdo3dK/xrWh09AyUuBVtN5py gySVRmq5bj7Khm1EsEzwIhKhOqSId2Xs4YwLUG6Qb4id2PUS4xp39KXHwUPpiZWw6+pW4AtcZ28Do r8tA5E52Q==; 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 1gCgPc-0007Ph-2U; Wed, 17 Oct 2018 07:38:36 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 530942029856B; Wed, 17 Oct 2018 09:38:33 +0200 (CEST) Date: Wed, 17 Oct 2018 09:38:33 +0200 From: Peter Zijlstra To: Waiman Long Cc: Ingo Molnar , Will Deacon , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] locking/qspinlock_stat: Count instances of nested lock slowpaths Message-ID: <20181017073833.GE3121@hirez.programming.kicks-ass.net> References: <1539697507-28084-1-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1539697507-28084-1-git-send-email-longman@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 16, 2018 at 09:45:06AM -0400, Waiman Long wrote: > Queued spinlock supports up to 4 levels of lock slowpath nesting - > user context, soft IRQ, hard IRQ and NMI. However, we are not sure how > often the nesting happens. So 3 more per-cpu stat counters are added > to track the number of instances where nesting index goes to 1, 2 and > 3 respectively. > > On a dual-socket 64-core 128-thread Zen server, the following were stat > counter values under different circumstances. > > State slowpath index1 index2 index3 > ----- -------- ------ ------ ------- > After bootup 1,012,150 82 0 0 > After parallel build + perf-top 125,195,009 82 0 0 Would probably be good to check a network workload.