[BUGFIX,IMPROVEMENT,V2,0/1] block, bfq: eliminate latency regression with fast drives
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Message ID 20190715105719.20353-1-paolo.valente@linaro.org
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  • block, bfq: eliminate latency regression with fast drives
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Paolo Valente July 15, 2019, 10:57 a.m. UTC
[V2 that should apply cleanly on current HEAD]

Hi Jens,
I've spotted a regression on a fast SSD: a loss of I/O-latency control
with interactive tasks (such as the application start up I usually
test). Details in the commit.

I do hope that, after proper review, this commit makes it for 5.3.

Thanks,
Paolo


Paolo Valente (1):
  block, bfq: check also in-flight I/O in dispatch plugging

 block/bfq-iosched.c | 67 +++++++++++++++++++++++++++++----------------
 1 file changed, 43 insertions(+), 24 deletions(-)

--
2.20.1

Comments

Jens Axboe July 16, 2019, 2:11 p.m. UTC | #1
On 7/15/19 4:57 AM, Paolo Valente wrote:
> [V2 that should apply cleanly on current HEAD]
> 
> Hi Jens,
> I've spotted a regression on a fast SSD: a loss of I/O-latency control
> with interactive tasks (such as the application start up I usually
> test). Details in the commit.
> 
> I do hope that, after proper review, this commit makes it for 5.3.

If it's a regression, it should have a Fixes: line telling us which
commit originally introduced the regression. This is important for
folks doing backports. Can you add that?
Paolo Valente July 18, 2019, 7:06 a.m. UTC | #2
> Il giorno 16 lug 2019, alle ore 16:11, Jens Axboe <axboe@kernel.dk> ha scritto:
> 
> On 7/15/19 4:57 AM, Paolo Valente wrote:
>> [V2 that should apply cleanly on current HEAD]
>> 
>> Hi Jens,
>> I've spotted a regression on a fast SSD: a loss of I/O-latency control
>> with interactive tasks (such as the application start up I usually
>> test). Details in the commit.
>> 
>> I do hope that, after proper review, this commit makes it for 5.3.
> 
> If it's a regression, it should have a Fixes: line telling us which
> commit originally introduced the regression. This is important for
> folks doing backports.

Right, sorry.

> Can you add that?
> 

Added, together with an explanation of why the fixed commit fails.

Sending a V3.

Thanks,
Paolo

> -- 
> Jens Axboe
>