Re: [PATCH BUGFIX/IMPROVEMENT V2 0/3] three bfq fixes restoring service guarantees with random sync writes in bg
From: Paolo Valente <hidden>
Date: 2017-08-31 17:13:04
Also in:
lkml
From: Paolo Valente <hidden>
Date: 2017-08-31 17:13:04
Also in:
lkml
Il giorno 31 ago 2017, alle ore 19:06, Mike Galbraith [off-list ref] =
ha scritto:
=20 On Thu, 2017-08-31 at 15:42 +0100, Mel Gorman wrote:quoted
On Thu, Aug 31, 2017 at 08:46:28AM +0200, Paolo Valente wrote:quoted
[SECOND TAKE, with just the name of one of the tester fixed] =20 Hi, while testing the read-write unfairness issues reported by Mel, I found BFQ failing to guarantee good responsiveness against heavy random sync writes in the background, i.e., multiple writers doing random writes and systematic fdatasync [1]. The failure was caused =
by
quoted
quoted
three related bugs, because of which BFQ failed to guarantee to high-weight processes the expected fraction of the throughput. =20=20 Queued on top of Ming's most recent series even though that's still a =
work
quoted
in progress. I should know in a few days how things stand.=20 It seems to have cured an interactivity issue I regularly meet during kbuild final link/depmod phase of fat kernel kbuild, especially bad with evolution mail usage during that on spinning rust. Can't really say for sure given this is not based on measurement. =20
Great! Actually, when I found these bugs, I thought also about the issues you told me you experienced with updatedb running. But then I forgot to tell you that these fixes might help. Thanks, Paolo
-Mike=20