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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 282FAC43331 for ; Fri, 6 Sep 2019 18:31:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 100D720674 for ; Fri, 6 Sep 2019 18:31:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436555AbfIFSbC (ORCPT ); Fri, 6 Sep 2019 14:31:02 -0400 Received: from mail-ot1-f66.google.com ([209.85.210.66]:33112 "EHLO mail-ot1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730881AbfIFSbB (ORCPT ); Fri, 6 Sep 2019 14:31:01 -0400 Received: by mail-ot1-f66.google.com with SMTP id g25so5359165otl.0; Fri, 06 Sep 2019 11:31:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=inlyOQUAj9IgrEa/tTn6FC+PgqOBuK2w0K+3C9jmY5A=; b=JQwQDjtYLZWP992ll5UVMiS2LzKBYMGWv8gfsVWoNQvMAZjF06y9OZ4GKs0FHpYhwA fwxMBKUA4dYJ7EJ+POoS5W8jiIexr6Aez4ABCUFRTfDnl5APQWz4JkjHZQM98oxWt7rA u93s8u4Gl3+kzKH/Fv36sPfDE6vVddSqffpmRuVQLVxVLx5XqVokyI5k4/Jm7d/vT/gi fgkkmCahRBDag+NJpsIy4tn/OubFL9Iouhd2Wroa0pxkDU+MFdgmlOpZ44iOTSOAfsOf SEmPv75W0FE/WITNmioBR64ER29PQEHcHzfcbpJemQXCIS/dALa0MAoYlp7Z92W6aZ+a xjxw== X-Gm-Message-State: APjAAAUqTtX+BwAM5pDJbMtVq0xZv8+PUxNMcOK4xcaIJsBMaaXQTTso pn8SFG5BD8ATMmYd8avL9Ng= X-Google-Smtp-Source: APXvYqxWAkAjBw9LI0HQBqKJ+CxguDMlNik/iXtNNjR5JA1VPQ+boOZQ7WXXD7Me44XzHY7PgXFxsw== X-Received: by 2002:a9d:66d2:: with SMTP id t18mr8790061otm.355.1567794660729; Fri, 06 Sep 2019 11:31:00 -0700 (PDT) Received: from ?IPv6:2600:1700:65a0:78e0:514:7862:1503:8e4d? ([2600:1700:65a0:78e0:514:7862:1503:8e4d]) by smtp.gmail.com with ESMTPSA id t30sm1086635otj.40.2019.09.06.11.30.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 Sep 2019 11:30:59 -0700 (PDT) Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism To: Daniel Lezcano , Ming Lei Cc: Jens Axboe , Hannes Reinecke , Bart Van Assche , linux-scsi@vger.kernel.org, Peter Zijlstra , Long Li , John Garry , LKML , linux-nvme@lists.infradead.org, Keith Busch , Ingo Molnar , Thomas Gleixner , Christoph Hellwig References: <20190903033001.GB23861@ming.t460p> <299fb6b5-d414-2e71-1dd2-9d6e34ee1c79@linaro.org> <20190903063125.GA21022@ming.t460p> <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> From: Sagi Grimberg Message-ID: <6eb2a745-7b92-73ce-46f5-cc6a5ef08abc@grimberg.me> Date: Fri, 6 Sep 2019 11:30:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org > > 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?