On 11/2/18 2:32 PM, Thomas Fjellstrom wrote: > On Saturday, October 27, 2018 1:20:10 PM MDT Jens Axboe wrote: >> On Oct 27, 2018, at 12:40 PM, Thomas Fjellstrom <[email protected]> > [snip] >> >> Can you try 4.19? A patch went in since 4.18 that fixes a starvation issue >> around requeue conditions, which SATA is the one to most often hit. >> >> Jens > > I just had to do a clean, and I have the mq kernel options I mentioned in my > previous mail enabled. (mq should be disabled) and it appears to still be > causing issues. current io scheduler appears to be cfq, and it took that > "make > clean" about 4 minutes, a lot of that time was spent with plasma, intelij, > and > chrome all starved of IO. > > I did switch to a terminal and checked iostat -d 1, and it showed very little > actual io for the time I was looking at it. > > I have no idea what's going on.
If you're using cfq, then it's not using mq at all. Maybe do something ala: # perf record -ag -- sleep 10 while the slowdown is happening and then do perf report -g --no-children and see if that yields anything interesting. Sounds like time is being spent elsewhere and you aren't actually waiting on IO. -- Jens Axboe
