Re: [PATCH V2] Consider inflight IO in io accounting for high latency devices

From: Bart Van Assche
Date: Mon Oct 16 2023 - 17:16:19 EST


On 10/16/23 13:01, Gulam Mohamed wrote:
[GULAM]: Yes, it will be called for every submitted bio but for the
high latency devices it will not have much impact. This is indicated
by the latency figures I provided in the review mail, with and
without our patch.

Calling tag iteration code from the hot path is wrong.

There are more devices than only hard disks that have a single hardware
queue, e.g. certain SSDs. I'm pretty sure that this patch will have a
significant negative performance impact for such devices.

Thanks,

Bart.