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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 56BC2C2BA19 for ; Mon, 6 Apr 2020 13:46:48 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0D8BA23341 for ; Mon, 6 Apr 2020 13:46:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D8BA23341 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48wsK06r5GzDqTh for ; Mon, 6 Apr 2020 23:46:44 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48wrQ43GNGzDqRy for ; Mon, 6 Apr 2020 23:06:04 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 48wrPs5VWNz9sRR; Mon, 6 Apr 2020 23:05:53 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 0c89649a70bed679fd408c1eb82fa99dbe1354a0 In-Reply-To: <20200402121212.1118218-1-npiggin@gmail.com> To: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org From: Michael Ellerman Subject: Re: [PATCH] powerpc/64s: Fix doorbell wakeup msgclr optimisation Message-Id: <48wrPs5VWNz9sRR@ozlabs.org> Date: Mon, 6 Apr 2020 23:05:53 +1000 (AEST) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nicholas Piggin Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, 2020-04-02 at 12:12:12 UTC, Nicholas Piggin wrote: > Commit 3282a3da25bd ("powerpc/64: Implement soft interrupt replay in C") > broke the doorbell wakeup optimisation introduced by commit a9af97aa0a12 > ("powerpc/64s: msgclr when handling doorbell exceptions from system > reset"). > > This patch restores it, in C code. It's moved explicitly to the system > reset wakeup path, rather than the doorbell replay path, because it is > always the right thing to do in the wakeup case, but it could be rare to > have a pending message in other cases in which case it's wasted work -- > we would have to be done to see if that was a worthwhile optimisation, > and I suspect it would not be. > > The results are similar to those in the original commit, test on POWER8 > of context_switch selftests benchmark with polling idle disabled (e.g., > always nap, giving cross-CPU IPIs) gives the following results: > > broken patched > Different threads, same core: 317k/s 375k/s +18.7% > Different cores: 280k/s 282k/s +1.0% > > Fixes: 3282a3da25bd ("powerpc/64: Implement soft interrupt replay in C") > Signed-off-by: Nicholas Piggin Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/0c89649a70bed679fd408c1eb82fa99dbe1354a0 cheers