Hello,
I looked into ccache usage on the LLVM build bots. Mehdi AMINI <joker....@gmail.com> writes: > On Wed, Jun 29, 2022 at 3:39 PM Maxim Kuvyrkov <maxim.kuvyr...@linaro.org> > wrote: > >> We have experimented with using zorg's CCACHE settings a few years back, >> and it turned out to be more robust to configure ccache at the level of >> default system (well, container) compiler. >> >> One thing to check is whether default 5GB cache limit fits us well. IIUC, >> flang builds are particularly big, and they may overflow the cache size. >> > > Oh yeah, anything under 20GB is likely doomed, in particular if you share > the cache across configs (like one machine building gcc and clang). Yes, we do share the cache like that. > Can you try to print cache statistics? Maybe tweak the job to clear the > stats before the job and print them after each build? We were using the default ccache size of 5 GB on all the LLVM bots. I have increased them now. Some machines have bigger and/or emptier disks than others, so I chose different cache sizes on different build hosts. I'll provide more detailed information in a separate email. The machine that does the flang-aarch64-latest-gcc job (and also flang-aarch64-latest-clang as well as other flang and clang jobs) has a big and relatively empty disk so I increased its cache size to 100 GB. >> > On 29 Jun 2022, at 16:33, David Spickett <david.spick...@linaro.org> >> wrote: >> > >> > While it's not visible in the zorg config we are using ccache. Except >> > we do it by setting the compiler to a script that runs the expected >> > clang/gcc via ccache. We can certainly look at using the ccache enable >> > in zorg instead (for the first attempt it was easier to do it in a way >> > we could control on our end). >> > >> > Looking at the our flang bots overall 2 hours seems to be the average >> > (out of tree is an outlier), I don't know anything about non Linaro >> > flang bots. We will check if there is some obvious bottleneck here but >> > we have resource constraints that limit how fast we can go even with >> > perfect caching. Are there any other bots you were interested in? We >> > can check those too. >> > >> > What build times were you expecting to see? It is useful for us to >> > know what expectations are even if, unfortunately, we don't meet them >> > at this time. >> > > flang-x86_64-knl-linux seems to to average 15-20min here, which is more > like I would expect. flang-aarch64-latest-gcc builds now take between 10m and 30m, with an occasional build taking 1h. flang-aarch64-latest-clang is similar. > Even there they could go much faster: we could avoid building the world and > only build flang and the test dependencies. Right now the bottleneck is > linking all of the LLVM tools that aren't relevant for testing flang. > > Compare with the way I set up the MLIR bots: > https://lab.llvm.org/buildbot/#/builders/61/builds/28582 > The build step here is exclusively building the binaries needed for running > `check-mlir` and nothing more. > > MLIR is smaller than flang, but we're still having a turnaround of 3-5 min > when the cache is hot. I haven't looked into that approach. -- Thiago _______________________________________________ linaro-toolchain mailing list -- linaro-toolchain@lists.linaro.org To unsubscribe send an email to linaro-toolchain-le...@lists.linaro.org
