> Il giorno 03 ago 2017, alle ore 11:42, Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> 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 <mgorman@xxxxxxxxxxxxxxxxxxx> 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 automatic testing >>> running every few weeks searching for regressions. Yesterday, it noticed >>> that creating some work files for a postgres simulator called pgioperf >>> was 38.33% slower and it auto-bisected to the switch to MQ. This is just >>> linearly writing two files for testing on another benchmark and is not >>> remarkable. The relevant part of the report is >> >> We saw some SCSI-MQ performance issue too, please see if the following >> patchset fixes your issue: >> >> http://marc.info/?l=linux-block&m=150151989915776&w=2 >> > > 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 or mq-deadline? Thanks, Paolo > -- > Mel Gorman > SUSE Labs
