Hi Vincent, >> >>> >>>> ------------------------------------------------------------ >>>> Here we have RT activity running on big CPU cluster induced with rt-app, >>>> and running hackbench in parallel. The RT tasks are bound to 4 CPUs on >>>> the big cluster (cpu 4,5,6,7) and have 100ms periodicity with >>>> runtime=20ms sleep=80ms. >>>> >>>> Hackbench shows big benefit (30%) improvement when number of tasks is 8 >>>> and 32: Note: data is completion time in seconds (lower is better). >>>> Number of loops for 8 and 16 tasks is 50000, and for 32 tasks its 20000. >>>> +--------+-----+-------+-------------------+---------------------------+ >>>> | groups | fds | tasks | Without Patch | With Patch | >>>> +--------+-----+-------+---------+---------+-----------------+---------+ >>>> | | | | Mean | Stdev | Mean | Stdev | >>>> | | | +-------------------+-----------------+---------+ >>>> | 1 | 8 | 8 | 1.0534 | 0.13722 | 0.7293 (+30.7%) | 0.02653 | >>>> | 2 | 8 | 16 | 1.6219 | 0.16631 | 1.6391 (-1%) | 0.24001 | >>>> | 4 | 8 | 32 | 1.2538 | 0.13086 | 1.1080 (+11.6%) | 0.16201 | >>>> +--------+-----+-------+---------+---------+-----------------+---------+ >>> >>> Out of curiosity, do you know why you don't see any improvement for >>> 16 tasks but only for 8 and 32 tasks ? >> >> Yes I'm not fully sure why 16 tasks didn't show that much improvement. > > Yes. This is just to make sure that there no unexpected side effect
Just got back from vacation. Tried to reproduce these results, looks like our product kernel changed enough that I am not able to exactly replicate these results and I don't recall the tree I ran these on. I will redo these tests and share my data in the next rev. Worst case I can probably drop this test, since there are other hackbench tests in this patch as well that show improvements. But I'll give it a shot to make sure no side effects from this. thanks. - Joel
