Re: Switching to MQ by default may generate some bug reports

On Wed, Aug 09, 2017 at 11:49:17PM +0200, Paolo Valente wrote: > > This discrepancy with your results makes a little bit harder for me to > > understand how to better proceed, as I see no regression. Anyway, > > since this reader-throttling issue seems relevant, I have investigated > > it a

Re: Switching to MQ by default may generate some bug reports

> Il giorno 08 ago 2017, alle ore 19:33, Paolo Valente > ha scritto: > >> >> Il giorno 08 ago 2017, alle ore 10:06, Paolo Valente >> ha scritto: >> >>> >>> Il giorno 07 ago 2017, alle ore 20:42, Paolo Valente >>>

Re: Switching to MQ by default may generate some bug reports

On Tue, Aug 08, 2017 at 07:33:37PM +0200, Paolo Valente wrote: > > Differently from bfq-sq, setting slice_idle to 0 doesn't provide any > > benefit, which lets me suspect that there is some other issue in > > blk-mq (only a suspect). I think I may have already understood how to > > guarantee that

Re: Switching to MQ by default may generate some bug reports

> Il giorno 08 ago 2017, alle ore 10:06, Paolo Valente > ha scritto: > >> >> Il giorno 07 ago 2017, alle ore 20:42, Paolo Valente >> ha scritto: >> >>> >>> Il giorno 07 ago 2017, alle ore 19:32, Paolo Valente >>>

Re: Switching to MQ by default may generate some bug reports

> Il giorno 08 ago 2017, alle ore 12:30, Mel Gorman > ha scritto: > > On Mon, Aug 07, 2017 at 07:32:41PM +0200, Paolo Valente wrote: global-dhp__io-dbench4-fsync-ext4 was a universal loss across any machine tested. This is global-dhp__io-dbench4-fsync

Re: Switching to MQ by default may generate some bug reports

On Tue, Aug 08, 2017 at 07:49:53PM +0800, Ming Lei wrote: > On Tue, Aug 8, 2017 at 7:27 PM, Mel Gorman > wrote: > > On Tue, Aug 08, 2017 at 06:43:03PM +0800, Ming Lei wrote: > >> Hi Mel Gorman, > >> > >> On Tue, Aug 8, 2017 at 6:30 PM, Mel Gorman

Re: Switching to MQ by default may generate some bug reports

> Il giorno 07 ago 2017, alle ore 20:42, Paolo Valente > ha scritto: > >> >> Il giorno 07 ago 2017, alle ore 19:32, Paolo Valente >> ha scritto: >> >>> >>> Il giorno 05 ago 2017, alle ore 00:05, Paolo Valente >>>

Re: Switching to MQ by default may generate some bug reports

> Il giorno 07 ago 2017, alle ore 19:32, Paolo Valente > ha scritto: > >> >> Il giorno 05 ago 2017, alle ore 00:05, Paolo Valente >> ha scritto: >> >>> >>> Il giorno 04 ago 2017, alle ore 13:01, Mel Gorman >>>

Re: Switching to MQ by default may generate some bug reports

> Il giorno 05 ago 2017, alle ore 13:54, Mel Gorman > ha scritto: > ... > >> In addition, as for coverage, we made the empiric assumption that >> start-up time measured with each of the above easy-to-benchmark >> applications gives an idea of the time that it would

Re: Switching to MQ by default may generate some bug reports

> Il giorno 05 ago 2017, alle ore 00:05, Paolo Valente > ha scritto: > >> >> Il giorno 04 ago 2017, alle ore 13:01, Mel Gorman >> ha scritto: >> >> On Fri, Aug 04, 2017 at 09:26:20AM +0200, Paolo Valente wrote: I took that into

Re: Switching to MQ by default may generate some bug reports

On Sat, Aug 05, 2017 at 12:05:00AM +0200, Paolo Valente wrote: > > > > True. However, the difference between legacy-deadline mq-deadline is > > roughly around the 5-10% mark across workloads for SSD. It's not > > universally true but the impact is not as severe. While this is not > > proof that

Re: Switching to MQ by default may generate some bug reports

> Il giorno 04 ago 2017, alle ore 13:01, Mel Gorman > ha scritto: > > On Fri, Aug 04, 2017 at 09:26:20AM +0200, Paolo Valente wrote: >>> I took that into account BFQ with low-latency was also tested and the >>> impact was not a universal improvement although it can

Re: Switching to MQ by default may generate some bug reports

On Fri, Aug 04, 2017 at 09:26:20AM +0200, Paolo Valente wrote: > > I took that into account BFQ with low-latency was also tested and the > > impact was not a universal improvement although it can be a noticable > > improvement. From the same machine; > > > > dbench4 Loadfile Execution Time > >

Re: Switching to MQ by default may generate some bug reports

> Il giorno 03 ago 2017, alle ore 13:01, Mel Gorman > ha scritto: > > On Thu, Aug 03, 2017 at 11:21:59AM +0200, Paolo Valente wrote: >>> For Paulo, if you want to try preemptively dealing with regression reports >>> before 4.13 releases then all the tests in

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 3, 2017 at 6:47 PM, Mel Gorman wrote: > On Thu, Aug 03, 2017 at 05:57:50PM +0800, Ming Lei wrote: >> On Thu, Aug 3, 2017 at 5:42 PM, Mel Gorman >> wrote: >> > On Thu, Aug 03, 2017 at 05:17:21PM +0800, Ming Lei wrote: >> >> Hi

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 03, 2017 at 11:21:59AM +0200, Paolo Valente wrote: > > For Paulo, if you want to try preemptively dealing with regression reports > > before 4.13 releases then all the tests in question can be reproduced with > > https://github.com/gormanm/mmtests . The most relevant test

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 03, 2017 at 05:57:50PM +0800, Ming Lei wrote: > On Thu, Aug 3, 2017 at 5:42 PM, Mel Gorman > wrote: > > On Thu, Aug 03, 2017 at 05:17:21PM +0800, Ming Lei wrote: > >> Hi Mel Gorman, > >> > >> On Thu, Aug 3, 2017 at 4:51 PM, Mel Gorman

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 03, 2017 at 11:44:06AM +0200, Paolo Valente wrote: > > That series is dealing with problems with legacy-deadline vs mq-none where > > as the bulk of the problems reported in this mail are related to > > legacy-CFQ vs mq-BFQ. > > > > Out-of-curiosity: you get no regression with

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 3, 2017 at 5:42 PM, Mel Gorman wrote: > On Thu, Aug 03, 2017 at 05:17:21PM +0800, Ming Lei wrote: >> Hi Mel Gorman, >> >> On Thu, Aug 3, 2017 at 4:51 PM, Mel Gorman >> wrote: >> > Hi Christoph, >> > >> > I know the reasons

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 03, 2017 at 05:17:21PM +0800, Ming Lei wrote: > Hi Mel Gorman, > > On Thu, Aug 3, 2017 at 4:51 PM, Mel Gorman > wrote: > > Hi Christoph, > > > > I know the reasons for switching to MQ by default but just be aware that > > it's > > not without hazards

Re: Switching to MQ by default may generate some bug reports

On Thu, Aug 3, 2017 at 5:17 PM, Ming Lei wrote: > Hi Mel Gorman, > > On Thu, Aug 3, 2017 at 4:51 PM, Mel Gorman > wrote: >> Hi Christoph, >> >> I know the reasons for switching to MQ by default but just be aware that it's >> not without

Re: Switching to MQ by default may generate some bug reports

> Il giorno 03 ago 2017, alle ore 10:51, Mel Gorman > ha scritto: > > Hi Christoph, > > I know the reasons for switching to MQ by default but just be aware that it's > not without hazards albeit it the biggest issues I've seen are switching > CFQ to BFQ. On my

Re: Switching to MQ by default may generate some bug reports

Hi Mel Gorman, On Thu, Aug 3, 2017 at 4:51 PM, Mel Gorman wrote: > Hi Christoph, > > I know the reasons for switching to MQ by default but just be aware that it's > not without hazards albeit it the biggest issues I've seen are switching > CFQ to BFQ. On my home