From: Ming Lei <ming.lei@redhat.com>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Keith Busch <keith.busch@intel.com>,
Hannes Reinecke <hare@suse.com>,
Bart Van Assche <bvanassche@acm.org>,
linux-scsi@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
Long Li <longli@microsoft.com>,
John Garry <john.garry@huawei.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-nvme@lists.infradead.org, Jens Axboe <axboe@fb.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism
Date: Sat, 7 Sep 2019 08:01:01 +0800 [thread overview]
Message-ID: <20190907000100.GC12290@ming.t460p> (raw)
In-Reply-To: <6eb2a745-7b92-73ce-46f5-cc6a5ef08abc@grimberg.me>
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
next prev parent reply other threads:[~2019-09-07 0:01 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 8:53 [PATCH 0/4] genirq/nvme: add IRQF_RESCUE_THREAD for avoiding IRQ flood Ming Lei
2019-08-27 8:53 ` [PATCH 1/4] softirq: implement IRQ flood detection mechanism Ming Lei
2019-08-27 14:42 ` Thomas Gleixner
2019-08-27 16:19 ` Thomas Gleixner
2019-08-27 23:04 ` Ming Lei
2019-08-27 23:12 ` Thomas Gleixner
2019-08-27 22:58 ` Ming Lei
2019-08-27 23:09 ` Thomas Gleixner
2019-08-28 11:06 ` Ming Lei
2019-08-28 11:23 ` Thomas Gleixner
2019-08-28 13:50 ` Ming Lei
2019-08-28 14:07 ` Thomas Gleixner
2019-09-03 3:30 ` Ming Lei
2019-09-03 5:59 ` Daniel Lezcano
2019-09-03 6:31 ` Ming Lei
2019-09-03 6:40 ` Daniel Lezcano
2019-09-03 7:28 ` Ming Lei
2019-09-03 7:50 ` Daniel Lezcano
2019-09-03 9:30 ` Ming Lei
2019-09-04 17:07 ` Bart Van Assche
2019-09-04 17:31 ` Daniel Lezcano
2019-09-04 17:38 ` Bart Van Assche
2019-09-04 18:02 ` Peter Zijlstra
2019-09-04 19:47 ` Bart Van Assche
2019-09-05 9:11 ` Ming Lei
2019-09-05 9:06 ` Ming Lei
2019-09-05 10:37 ` Daniel Lezcano
2019-09-06 1:22 ` Long Li
2019-09-06 4:36 ` Daniel Lezcano
2019-09-06 4:44 ` Long Li
2019-09-06 1:48 ` Ming Lei
2019-09-06 5:14 ` Daniel Lezcano
2019-09-06 18:30 ` Sagi Grimberg
2019-09-06 18:52 ` Keith Busch
2019-09-07 0:01 ` Ming Lei [this message]
2019-09-10 3:10 ` Sagi Grimberg
2019-09-18 0:00 ` Long Li
2019-09-20 17:14 ` Sagi Grimberg
2019-09-20 19:12 ` Long Li
2019-09-20 20:45 ` Sagi Grimberg
2019-09-24 0:57 ` Long Li
2019-09-18 14:37 ` Ming Lei
2019-09-20 17:09 ` Sagi Grimberg
2019-09-06 14:18 ` Keith Busch
2019-09-06 17:50 ` Long Li
2019-09-06 22:19 ` Ming Lei
2019-09-06 22:25 ` Keith Busch
2019-09-06 23:13 ` Ming Lei
2019-09-10 0:24 ` Ming Lei
2019-09-03 8:09 ` Thomas Gleixner
2019-09-03 9:24 ` Ming Lei
2019-08-29 6:15 ` Long Li
2019-08-30 0:55 ` Ming Lei
2019-08-27 8:53 ` [PATCH 2/4] genirq: add IRQF_RESCUE_THREAD Ming Lei
2019-08-27 8:53 ` [PATCH 3/4] nvme: pci: pass IRQF_RESCURE_THREAD to request_threaded_irq Ming Lei
2019-08-27 9:06 ` Johannes Thumshirn
2019-08-27 9:09 ` Ming Lei
2019-08-27 9:12 ` Johannes Thumshirn
2019-08-27 14:34 ` Keith Busch
2019-08-27 14:44 ` Keith Busch
2019-08-27 15:10 ` Bart Van Assche
2019-08-28 1:45 ` Ming Lei
2019-08-27 8:53 ` [PATCH 4/4] genirq: use irq's affinity for threaded irq with IRQF_RESCUE_THREAD Ming Lei
2019-08-27 14:35 ` Keith Busch
2019-09-06 8:50 ` John Garry
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