multithreaded yum-presto Koji builds for F16 and F17

[Andre Robatino]

drago01 <drago01 <at> gmail.com> writes:

> Here it went up from 1.2MB/s to 2.1-2.6MB/s (4 cores - 8 threads). Not
> sure how many threads it actually uses but this is not a linear
> speedup. Disk is an SSD as well.

I asked Jonathan Dieter about the speedup in the bug and he responded in
https://bugzilla.redhat.com/show_bug.cgi?id=701711#c13 . I was aware that
applydeltarpm itself is not threaded (which is probably not feasible, at least
with any hope of a linear speedup) and that yum-presto instead runs multiple
instances of it in different threads. To get a linear speedup, you'd need both
for I/O not to be an issue, and for there to be enough drpms to keep all N cores
busy simultaneously. If there are only a few drpms, or some are much larger than
others, that won't happen. Of course, it's good to do updates often, but that
means relatively few drpms each time. Not as good as I expected, unfortunately.