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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 0C46CC00307 for ; Sat, 7 Sep 2019 00:01:22 +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 D78B6208C3 for ; Sat, 7 Sep 2019 00:01:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LECD13ma" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D78B6208C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=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=4dM/rwRHIQ3m++hxwKrmKOTDtmND9Cm5DjRfO7GBA2s=; b=LECD13maUlT6y/ B4cjwe1DrP37n6fNOfzlZarqqtnjmAZcq5tiC1eBf7pZdmewkQiAgSFJyVxwGj1EN3HPRuzsCvO7X rIlTSA82BRLFQ5Yjf9ke+SAiu6vbOOkyDXD/quYqJdoSdRe5USFqWb/NtORXS2FN1YLdoCpngLohc OICTOeRPqsQts5+LdULJDjkuvmIr5FaeewX4I/WACrXPcPi7iTbpIZ7TueqKgZUTVx+SHPz7QXJXM T8YblobN/vtCcrHfERStjR4OKe/z9XRjN5SXIb9RyFc+HKU6cesr6929JGZ+5CTflToRWyqmdQ/tK JK5DBVFpVRVZH0yLAc0w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i6OAK-0001us-3o; Sat, 07 Sep 2019 00:01:20 +0000 Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i6OAH-0001uY-F9 for linux-nvme@lists.infradead.org; Sat, 07 Sep 2019 00:01:19 +0000 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 75B9FA46C07; Sat, 7 Sep 2019 00:01:16 +0000 (UTC) Received: from ming.t460p (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 764675D9CA; Sat, 7 Sep 2019 00:01:06 +0000 (UTC) Date: Sat, 7 Sep 2019 08:01:01 +0800 From: Ming Lei To: Sagi Grimberg Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism Message-ID: <20190907000100.GC12290@ming.t460p> References: <6b88719c-782a-4a63-db9f-bf62734a7874@linaro.org> <20190903072848.GA22170@ming.t460p> <6f3b6557-1767-8c80-f786-1ea667179b39@acm.org> <2a8bd278-5384-d82f-c09b-4fce236d2d95@linaro.org> <20190905090617.GB4432@ming.t460p> <6a36ccc7-24cd-1d92-fef1-2c5e0f798c36@linaro.org> <20190906014819.GB27116@ming.t460p> <6eb2a745-7b92-73ce-46f5-cc6a5ef08abc@grimberg.me> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <6eb2a745-7b92-73ce-46f5-cc6a5ef08abc@grimberg.me> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Sat, 07 Sep 2019 00:01:16 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190906_170117_530384_D583A127 X-CRM114-Status: GOOD ( 14.93 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Hannes Reinecke , John Garry , Bart Van Assche , linux-scsi@vger.kernel.org, Peter Zijlstra , Long Li , Daniel Lezcano , LKML , linux-nvme@lists.infradead.org, Keith Busch , Ingo Molnar , Thomas Gleixner , Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Sep 06, 2019 at 11:30:57AM -0700, Sagi Grimberg wrote: > > > > > Ok, so the real problem is per-cpu bounded tasks. > > > > I share Thomas opinion about a NAPI like approach. > > We already have that, its irq_poll, but it seems that for this > use-case, we get lower performance for some reason. I'm not > entirely sure why that is, maybe its because we need to mask interrupts > because we don't have an "arm" register in nvme like network devices > have? Long observed that IOPS drops much too by switching to threaded irq. If softirqd is waken up for handing softirq, the performance shouldn't be better than threaded irq. Especially, Long found that context switch is increased a lot after applying your irq poll patch. http://lists.infradead.org/pipermail/linux-nvme/2019-August/026788.html Thanks, Ming _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme