22.09.2014 10:28, I wrote: > 22.09.2014 05:20, David Henningsson wrote: >> On 2014-09-21 12:28, Alexander E. Patrakov wrote: >>> 21.09.2014 16:19, Tanu Kaskinen wrote: >>>> Patch review status updated: >>>> http://www.freedesktop.org/wiki/Software/PulseAudio/PatchStatus/ >>> >>> "Reduce hardware pointer update syscalls" is not exactly "waiting for >>> review". I have tested it and found it to fail an assertion when the >>> sink is autosuspended. Also I did some profiling using perf, but testing >>> on one card does not give enough justification to reject the patch on >>> the "no performance improvement" basis. It does look like a valid >>> cleanup and simplification attempt, though. >>> >>> Of course this cannot count as a proper review, but, due to the failed >>> assertion, the need for a new version of the patch is quite obvious at >>> this point. >> >> I'm currently waiting for Peter to see if he notices any substantial >> perfomance improvements on his card(s). If he does, it makes sense to >> submit a new, and more robust, version. If not, maybe it's easier to >> just drop the idea (no use optimising things that don't take much time >> anyway). > > I think it may still be a valid optimization, but only when combined > with the removal of the loop that increases j from mmap_write() and > unix_write(). I.e., currently, there may be several attempts to write > data, i.e. several syscalls that move the pointer (via writei or > mmap_commit). In the worst case, by asking Peter to test the version > that still has the loop about j, you are wasting his time. Sorry for the last phrase. In the worst case, by asking to try removing the j loop, I am wasting your time. So, your choice what to do next. -- Alexander E. Patrakov
