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([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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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?