RE: [PATCH v5 00/14] blk-mq: Reduce static requests memory footprint for shared sbitmap

From: Kashyap Desai
Date: Tue Oct 05 2021 - 10:03:43 EST


> -----Original Message-----
> From: John Garry [mailto:john.garry@xxxxxxxxxx]
> Sent: Tuesday, October 5, 2021 7:05 PM
> To: Jens Axboe <axboe@xxxxxxxxx>; kashyap.desai@xxxxxxxxxxxx
> Cc: linux-block@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> ming.lei@xxxxxxxxxx; hare@xxxxxxx; linux-scsi@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 00/14] blk-mq: Reduce static requests memory
> footprint for shared sbitmap
>
> On 05/10/2021 13:35, Jens Axboe wrote:
> >> Baseline is 1b2d1439fc25 (block/for-next) Merge branch
> >> 'for-5.16/io_uring'
> >> into for-next
> > Let's get this queued up for testing, thanks John.
>
> Cheers, appreciated
>
> @Kashyap, You mentioned that when testing you saw a performance
> regression from v5.11 -> v5.12 - any idea on that yet? Can you describe
> the
> scenario, like IO scheduler and how many disks and the type? Does
> disabling
> host_tagset_enable restore performance?

John - I am still working on this. System was not available due to some
other debugging.

>
> From checking differences between those kernels, I don't see anything
> directly relevant in sbitmap support or in the megaraid sas driver.
>
> Thanks,
> John

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