On 7/13/21 9:49 AM, Bart Van Assche wrote:
On 7/11/21 5:29 AM, Avri Altman wrote:
This patch is a performance improvement because it reduces the number of
atomic operations in the hot path (test_and_clear_bit()).
Both Can & Stanley reported a performance improvement of RR with
"Optimize host lock..".
Can those short numerical studies can be repeated with this patch?
I will measure the performance impact of this patch for rq_affinity=2 as
soon as I have the time. As you may know we are close to an internal
deadline.
(replying to my own email)
Hi Avri,
The performance I measure with the current upstream UFS driver is 61.0 K
IOPS. With a variant of this patch (outstanding_reqs protected with a
new spinlock instead of the host lock), I see 62.0 K IOPS. In other
words, this patch realizes a small performance improvement. This is what
I had expected since this patch reduces the number of atomic operations
involved in updating outstanding_reqs.
Thanks,
Bart.
