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

Long Li
2019-09-06T04:44:06Z

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

It's just IRQ_TIME_ACCOUNTING.

>
>
>> 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
>/nv
>>
>me4n1:/dev/nvme5n1:/dev/nvme6n1:/dev/nvme7n1:/dev/nvme8n1:/dev/n
>vme9n1
>> --direct=1 --runtime=12000 --numjobs=80 --rw=randread --name=test
>> --group_reporting --gtod_reduce=1
>
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