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 Thanks, Ming
