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

Switching to MQ by default may generate some bug reports

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 grid, there is some experimental automatic testing running every few weeks searching for regressions.