On Mon, Jul 31, 2023 at 02:04:42PM +0200, Thomas Huth wrote: > On 31/07/2023 11.32, Daniel P. Berrangé wrote: > > On Mon, Jul 31, 2023 at 11:10:58AM +0200, Thomas Huth wrote: > ... > > > Or do you see another possibility how we could fix that timeout problem in > > > the 64-bit MSYS2 job? Still switching to clang, but compiling with > > > --extra-cflags="-Wno-unknown-attributes" maybe? > > > > I was surprised to see that we're not using ccache in gitlab CI. It wouldn't > > help the from-clean compile time, but thereafter it ought to help. I'm doing > > some tests with that to see the impact. > > I tried that two years ago, but the results were rather disappointing: > > https://lists.nongnu.org/archive/html/qemu-devel/2021-04/msg02189.html > > ... but that was only with the Linux runners. Maybe it helps with the MSYS > runners?
I've done some tests over the last few days and my results are rather different. The speed up is *spectacular* if the hit rate is high. eg, consider you are retriggering broadly the same pipeline over & over with iterations of your patches. eg 99% of the QEMU code probably doesn't change as you're just re-trying to fix some edge case in 1 file, and thus you'll get near 100% hit rate. With such a case I see: The msys64 job can complete in 24 minutes, instead of 50-60 minutes The build-system-fedora job can complete in 6 minutes instead of 20 minutes The build-user-hexagon job can cmplete in 3 minutes instead of 6 Basically a 50% cut in time on all compile jobs I've looked at so far. NB, these are both shared runners, since the pipeline is in my fork. I've no idea what the impact will be on the Azure private runners for upstream. Given the CI limitations these days, such a speedup is massively beneficial for our contributors though. The downside is storage for the cache. In theory gitlab has defined a quota for storage per account. In practice they are still yet to enforce that. If they do ever enforce it, we're likely doomed as our container images alone will exceed it several times over, let alone leave room for build logs, job caches, artifacts, etc. While storage quota isn't enforced though, we might as well use ccache. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
