Messages in this thread |  | | | Date | Tue, 10 Jan 2006 16:31:21 -0600 | | From | Joel Schopp <> | | Subject | Re: PowerPC fastpaths for mutex subsystem |
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> interesting. Could you try two things? Firstly, could you add some > minimal delays to the lock/unlock path, of at least 1 usec? E.g. > "synchro-test.ko load=1 interval=1". [but you could try longer delays > too, 10 usecs is still realistic.]
Graphs attached. The summary for those who don't like to look at attachments is that the mutex fastpath (threads 1) that I sent the optimized patch for is comparable within the margin of error to semaphores. The mutex common path (threads > 1) gets embarrassed by semaphores. So mutexes common paths are not yet ready as far as ppc64 is concerned. > > secondly, could you try the VFS creat+unlink test via the test-mutex.c > code below, with something like: > > ./test-mutex V 16 10
Queued into my todo list.
> > thirdly, could you run 'vmstat 1' during the tests, and post those lines > too? Here i'm curious about two things: the average runqueue length > (whether we have overscheduling), and CPU utilization and idle time left > (how efficiently cycles are preserved in contention). [btw., does ppc > have an idle=poll equivalent mode of idling?]
Also queued in my todo list.
> > also, there seems to be some fluctuation in the numbers - could you try > to run a few more to see how stable the numbers are?
For the graphs the line is the average of 5 runs, and the 5 runs are scatter plotted as well. [image][image][image] |  |