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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 67CF3C43331 for ; Fri, 6 Sep 2019 19:01:20 +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 3A39A2082C for ; Fri, 6 Sep 2019 19:01:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Z+hqjvQy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A39A2082C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=uVq5mJvJhmQaBLFn1Wp+qo8/naClziAKeTk3z8gcfiA=; b=Z+hqjvQyWt6p2k yqAtu/uWI3o7sylZndX0j6J/jR5cWsR5vF/HQn/E3qeHJhGWx8CvpoQDUgz1C/FvJm+PcyE+EQKGF BYCUdmRyfIcfn2y0ZzPahmFW0NTFZGq1W63KnoaKMjVdO5QCnx49PtL3okN+8Yi9x11mwgi2c5Xuy 3jYP0f2PmrKACkxKDTNLvHF5PkknYykrGfnIgm5k3OsFn9Loa3N3S9FMcdvDx4GCjSjPsoM05Jhho xq1oJKdJxgJp6OCGjPDNPkrGblm9TWHoSxp84ZYvnoSd8Qm5cBmXMn8Cb6J5TXvsEmqlAmVgoibkb eRMbYhEgR3Y5Kh5PN5Aw==; 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 1i6JTx-0005fJ-0h; Fri, 06 Sep 2019 19:01:17 +0000 Received: from mga14.intel.com ([192.55.52.115]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i6JTu-0005ef-QN for linux-nvme@lists.infradead.org; Fri, 06 Sep 2019 19:01:15 +0000 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Sep 2019 12:01:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,474,1559545200"; d="scan'208";a="190907127" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by FMSMGA003.fm.intel.com with ESMTP; 06 Sep 2019 12:01:11 -0700 Date: Fri, 6 Sep 2019 12:52:11 -0600 From: Keith Busch To: Sagi Grimberg Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism Message-ID: <20190906185210.GA4260@localhost.localdomain> 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/1.9.1 (2017-09-22) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190906_120114_867175_A5521B37 X-CRM114-Status: GOOD ( 12.66 ) 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: Keith Busch , Hannes Reinecke , John Garry , Bart Van Assche , linux-scsi@vger.kernel.org, Peter Zijlstra , Long Li , Daniel Lezcano , LKML , linux-nvme@lists.infradead.org, Ming Lei , Jens Axboe , 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? For MSI, that's the INTMS/INTMC NVMe registers. MSI-x, though, has to disarm it in its table entry, and the Linux implementation will do a posted read in that path, which is a bit too expensive. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme