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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 1FB61CA9EA0 for ; Fri, 18 Oct 2019 11:46:05 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 DF4AB20700 for ; Fri, 18 Oct 2019 11:46:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qenJjHIJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF4AB20700 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yGVP2X6u7uVr+LGm5PGN4qrJpfhdoZ/jCQAF6egFt2s=; b=qenJjHIJTvY52i DJSQqTG2Z4xJv3glUZhNqQHMiGQ865RwXD55l9XEU7SKQNpsL+W/1bGMEZwIj8QYZNbIConFUbEgn +nqTrrGnkEUjGIuktknLIj4QuvPVLeokFI5tHP8f5eVSah07YebgbZiEzdxF3DM5VPe1ClisI3Ud/ 7VBq1ILv+gyOb4qJq+44dXD7qRMlUnhUxGxPl6TDsvneLnNDgOqSkTI02Mkl2kh44pzpZ8322qPww U+im9oMnTrvmopFrAsZN2Bqyw37Oa16vo255yQNcnae6VbNDla6+2pAIMN+gV2Gv+hJ1829gZE4/W dhjKpof+rpw8Frim7qIg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iLQhi-0002h4-Eq; Fri, 18 Oct 2019 11:45:58 +0000 Received: from [217.140.110.172] (helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iLQhf-0002cc-To for linux-arm-kernel@lists.infradead.org; Fri, 18 Oct 2019 11:45:57 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4D43DCA3; Fri, 18 Oct 2019 04:45:45 -0700 (PDT) Received: from bogus (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7F1EE3F6C4; Fri, 18 Oct 2019 04:45:43 -0700 (PDT) Date: Fri, 18 Oct 2019 12:45:29 +0100 From: Sudeep Holla To: Yunfeng Ye Subject: Re: [PATCH V3] arm64: psci: Reduce waiting time for cpu_psci_cpu_kill() Message-ID: <20191018114529.GA15116@bogus> References: <433980c7-f246-f741-f00c-fce103a60af7@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <433980c7-f246-f741-f00c-fce103a60af7@huawei.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191018_044556_004469_836BC2C8 X-CRM114-Status: GOOD ( 21.41 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kstewart@linuxfoundation.org, lorenzo.pieralisi@arm.com, ard.biesheuvel@linaro.org, "hushiyuan@huawei.com" , catalin.marinas@arm.com, linux-kernel@vger.kernel.org, "linfeilong@huawei.com" , David.Laight@ACULAB.COM, gregkh@linuxfoundation.org, tglx@linutronix.de, wuyun.wu@huawei.com, will@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Oct 18, 2019 at 07:24:14PM +0800, Yunfeng Ye wrote: > In a case like suspend-to-disk, a large number of CPU cores need to be Add suspend-to-ram also to list, i.e. "In case like suspend-to-disk and suspend-to-ram, a large number..." > shut down. At present, the CPU hotplug operation is serialised, and the > CPU cores can only be shut down one by one. In this process, if PSCI > affinity_info() does not return LEVEL_OFF quickly, cpu_psci_cpu_kill() > needs to wait for 10ms. If hundreds of CPU cores need to be shut down, > it will take a long time. > > Normally, it is no need to wait 10ms in cpu_psci_cpu_kill(). So change s/it is/there is/ > the wait interval from 10 ms to max 1 ms and use usleep_range() instead > of msleep() for more accurate schedule. > s/for more accurate schedule/for more accurate timer/ > In addition, reduce the time interval will increase the messages output, s/reduce/reducing/ > so remove the "Retry ..." message, instead, put the number of waiting > times to the sucessful message. > > Signed-off-by: Yunfeng Ye > --- > v2 -> v3: > - update the comment > - remove the busy-wait logic, modify the loop logic and output message > > v1 -> v2: > - use usleep_range() instead of udelay() after waiting for a while > > arch/arm64/kernel/psci.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c > index c9f72b2665f1..00b8c0825a08 100644 > --- a/arch/arm64/kernel/psci.c > +++ b/arch/arm64/kernel/psci.c > @@ -91,15 +91,14 @@ static int cpu_psci_cpu_kill(unsigned int cpu) > * while it is dying. So, try again a few times. > */ > > - for (i = 0; i < 10; i++) { > + for (i = 0; i < 100; i++) { > err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); > if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { > - pr_info("CPU%d killed.\n", cpu); > + pr_info("CPU%d killed by waiting %d loops.\n", cpu, i); > return 0; > } > > - msleep(10); > - pr_info("Retrying again to check for CPU kill\n"); > + usleep_range(100, 1000); Since usleep_range can return anytime between 100us to 1ms, does it make sense to check for (time_before(jiffies, timeout)) you had in v2 ? -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel