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

2017-08-10 Thread Mel Gorman
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 little

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

2017-08-09 Thread Paolo Valente
> 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 >>> ha scritto: >>> Il giorno 07 ago 2017, alle ore 19:32, Paolo Va

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

2017-08-08 Thread Mel Gorman
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

2017-08-08 Thread Paolo Valente
> 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 >>> ha scritto: >>> Il giorno 05 ago 2017, alle ore 00:05, Paolo Va

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

2017-08-08 Thread Paolo Valente
> 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 from mmtests using ext4 as a

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

2017-08-08 Thread Mel Gorman
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 > >> wrote: > >> > >> > > >> > o I've queue

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

2017-08-08 Thread Ming Lei
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 >> wrote: >> >> > >> > o I've queued a subset of tests with Ming's v3 patchset as that was the >> > latest branc

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

2017-08-08 Thread Mel Gorman
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 > wrote: > > > > > o I've queued a subset of tests with Ming's v3 patchset as that was the > > latest branch at the time I looked. It'll take quite some time to execut

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

2017-08-08 Thread Ming Lei
Hi Mel Gorman, On Tue, Aug 8, 2017 at 6:30 PM, Mel Gorman wrote: > > o I've queued a subset of tests with Ming's v3 patchset as that was the > latest branch at the time I looked. It'll take quite some time to execute > as the grid I use to collect data is backlogged with other work The

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

2017-08-08 Thread Mel Gorman
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 from mmtests using > >> ext4 as a filesystem. The same is not true for XFS so the filesystem > >> matters.

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

2017-08-08 Thread Paolo Valente
> 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 >>> ha scritto: >>> Il giorno 04 ago 2017, alle ore 13:01, Mel Gorm

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

2017-08-07 Thread Paolo Valente
> 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 >>> ha scritto: >>> >>> On Fri, Aug 04, 2017 at 09:26:20AM +0200, Paolo Valente w

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

2017-08-07 Thread Paolo Valente
> 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 take with any >> application

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

2017-08-07 Thread Paolo Valente
> 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 account BFQ with low-latency was also tested and the

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

2017-08-05 Thread Mel Gorman
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 th

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

2017-08-04 Thread Paolo Valente
> 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 be a noticable >>> improvemen

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

2017-08-04 Thread Mel Gorman
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

2017-08-04 Thread Paolo Valente
> 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 question can be reproduced with >>>

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

2017-08-03 Thread Ming Lei
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 Mel Gorman, >> >> >> >> On Thu, Aug 3, 2017 at 4:51 PM, Me

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

2017-08-03 Thread Mel Gorman
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 configurations

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

2017-08-03 Thread Mel Gorman
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 > >> wrote: > >> > Hi Christoph, > >> > > >> > I

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

2017-08-03 Thread Mel Gorman
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 mq-none

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

2017-08-03 Thread Ming Lei
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 for switching to MQ by default but just be aware that >> > i

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

2017-08-03 Thread Paolo Valente
> Il giorno 03 ago 2017, alle ore 11:42, Mel Gorman > ha scritto: > > 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 b

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

2017-08-03 Thread Mel Gorman
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 albeit it the biggest issues I'v

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

2017-08-03 Thread Ming Lei
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 hazards albeit it the biggest issues I've seen are switchin

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

2017-08-03 Thread Paolo Valente
> 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 home grid, there is some experime

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

2017-08-03 Thread Ming Lei
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 grid, there is some experimental a

Switching to MQ by default may generate some bug reports

2017-08-03 Thread Mel Gorman
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. Yesterda