On Wed, Jul 6, 2022 at 9:40 PM Thiago Jung Bauermann < thiago.bauerm...@linaro.org> wrote:
> > 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. > That's a huge improvement! :) > > > 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
