Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism

Daniel Lezcano
2019-09-06T04:36:31Z

On 06/09/2019 03:22, Long Li wrote:
[ ... ]
>

> Tracing shows that the CPU was in either hardirq or softirq all the
> time before warnings. During tests, the system was unresponsive at
> times.
>
> Ming's patch fixed this problem. The system was responsive throughout
> tests.
>
> As for performance hit, both resulted in a small drop in peak IOPS.
> With IRQ_TIME_ACCOUNTING I see a 3% drop. With Ming's patch it is 1%
> drop.

Do you mean IRQ_TIME_ACCOUNTING + irq threaded ?

> For the tests, I used the following fio command on 10 NVMe disks: fio
> --bs=4k --ioengine=libaio --iodepth=128
> --filename=/dev/nvme0n1:/dev/nvme1n1:/dev/nvme2n1:/dev/nvme3n1:/dev/nvme4n1:/dev/nvme5n1:/dev/nvme6n1:/dev/nvme7n1:/dev/nvme8n1:/dev/nvme9n1
> --direct=1 --runtime=12000 --numjobs=80 --rw=randread --name=test
> --group_reporting --gtod_reduce=1

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