From: Thomas Gleixner <tglx@linutronix.de>
To: xuyihang <xuyihang@huawei.com>, Ming Lei <ming.lei@redhat.com>
Cc: Peter Xu <peterx@redhat.com>, Christoph Hellwig <hch@lst.de>,
Jason Wang <jasowang@redhat.com>,
Luiz Capitulino <lcapitulino@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
minlei@redhat.com, liaochang1@huawei.com
Subject: Re: Virtio-scsi multiqueue irq affinity
Date: Mon, 10 May 2021 21:56:48 +0200 [thread overview]
Message-ID: <87wns6gy67.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <963e38b0-a7d6-0b13-af89-81b03028d1ae@huawei.com>
Yihang,
On Mon, May 10 2021 at 16:48, xuyihang wrote:
> 在 2021/5/8 20:26, Thomas Gleixner 写道:
>> Can you please provide a more detailed description of your system?
>> - Kernel version
> This experiment run on linux-4.19
Again. Please provide reports against the most recent mainline version
and not against some randomly picked kernel variant.
> If we make some change on this experiment:
>
> 1. Make this RT application use less CPU time instead of 100%, the problem
> disappear.
>
> 2, If we change rq_affinity to 2, in order to avoid handle softirq on
> the same core of RT thread, the problem also disappear. However, this approach
> result in about 10%-30% random write proformance deduction comparing
> to rq_affinity = 1, since it may has better cache utilization.
> echo 2 > /sys/block/sda/queue/rq_affinity
>
> Therefore, I want to exclude some CPU from managed irq on boot
> parameter,
Why has this realtime thread to run on CPU0 and cannot move to some
other CPU?
> which has simliar approach to 11ea68f553e2 ("genirq, sched/isolation:
> Isolate from handling managed interrupts").
Why can't you use the existing isolation mechanisms?
Thanks,
tglx
next prev parent reply other threads:[~2021-05-10 19:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 6:21 Virtio-scsi multiqueue irq affinity Peter Xu
2019-03-23 17:15 ` Thomas Gleixner
2019-03-25 5:02 ` Peter Xu
2019-03-25 7:06 ` Ming Lei
2019-03-25 8:53 ` Thomas Gleixner
2019-03-25 9:43 ` Peter Xu
2019-03-25 13:27 ` Thomas Gleixner
2019-03-25 9:50 ` Ming Lei
2021-05-08 7:52 ` xuyihang
2021-05-08 12:26 ` Thomas Gleixner
2021-05-10 3:19 ` liaochang (A)
2021-05-10 7:54 ` Thomas Gleixner
2021-05-18 1:37 ` liaochang (A)
2021-05-10 8:48 ` xuyihang
2021-05-10 19:56 ` Thomas Gleixner [this message]
2021-05-11 12:38 ` xuyihang
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