From: Keith Busch <kbusch@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@fb.com>, Hannes Reinecke <hare@suse.com>,
John Garry <john.garry@huawei.com>,
Bart Van Assche <bvanassche@acm.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Long Li <longli@microsoft.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
Keith Busch <keith.busch@intel.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism
Date: Fri, 6 Sep 2019 16:25:55 -0600 [thread overview]
Message-ID: <20190906222555.GB4260@localhost.localdomain> (raw)
In-Reply-To: <20190906221920.GA12290@ming.t460p>
On Sat, Sep 07, 2019 at 06:19:21AM +0800, Ming Lei wrote:
> On Fri, Sep 06, 2019 at 05:50:49PM +0000, Long Li wrote:
> > >Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism
> > >
> > >Why are all 8 nvmes sharing the same CPU for interrupt handling?
> > >Shouldn't matrix_find_best_cpu_managed() handle selecting the least used
> > >CPU from the cpumask for the effective interrupt handling?
> >
> > The tests run on 10 NVMe disks on a system of 80 CPUs. Each NVMe disk has 32 hardware queues.
>
> Then there are total 320 NVMe MSI/X vectors, and 80 CPUs, so irq matrix
> can't avoid effective CPUs overlapping at all.
Sure, but it's at most half, meanwhile the CPU that's dispatching requests
would naturally be throttled by the other half who's completions are
interrupting that CPU, no?
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next prev parent reply other threads:[~2019-09-06 22:35 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190827085344.30799-1-ming.lei@redhat.com>
[not found] ` <20190827085344.30799-2-ming.lei@redhat.com>
[not found] ` <alpine.DEB.2.21.1908271633450.1939@nanos.tec.linutronix.de>
[not found] ` <20190827225827.GA5263@ming.t460p>
[not found] ` <alpine.DEB.2.21.1908280104330.1939@nanos.tec.linutronix.de>
[not found] ` <20190828110633.GC15524@ming.t460p>
[not found] ` <alpine.DEB.2.21.1908281316230.1869@nanos.tec.linutronix.de>
[not found] ` <20190828135054.GA23861@ming.t460p>
[not found] ` <alpine.DEB.2.21.1908281605190.23149@nanos.tec.linutronix.de>
2019-09-03 3:30 ` [PATCH 1/4] softirq: implement IRQ flood detection mechanism 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
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 [this message]
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
[not found] ` <20190827085344.30799-5-ming.lei@redhat.com>
2019-09-06 8:50 ` [PATCH 4/4] genirq: use irq's affinity for threaded irq with IRQF_RESCUE_THREAD John Garry
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