All, I have a suspicion this will help my efforts increasing the IOPS ability of mdraid in 10-12 NVMe drive per raid group situations. Pure neophyte question, which I apologize for in advance, how can I test this? Does this end up in a 5.15 release candidate kernel? I want to make contributions wherever I can, as I have hardware and needs, so I can act as a performance validator within reason. I know I can't make contributions as a developer, but I'm willing to contribute in areas where our goals are in alignment and this appears to be one. Regards, Jim -----Original Message----- From: Jens Axboe <axboe@xxxxxxxxx> Sent: Tuesday, September 7, 2021 7:06 PM To: Song Liu <songliubraving@xxxxxx>; linux-block@xxxxxxxxxxxxxxx; linux-raid@xxxxxxxxxxxxxxx Cc: marcin.wanat@xxxxxxxxx Subject: [Non-DoD Source] Re: [PATCH] blk-mq: allow 4x BLK_MAX_REQUEST_COUNT at blk_plug for multiple_queues On 9/7/21 5:03 PM, Song Liu wrote: > Limiting number of request to BLK_MAX_REQUEST_COUNT at blk_plug hurts > performance for large md arrays. [1] shows resync speed of md array > drops for md array with more than 16 HDDs. > > Fix this by allowing more request at plug queue. The multiple_queue > flag is used to only apply higher limit to multiple queue cases. Applied, thanks. -- Jens Axboe
