Re: [ccache] Radically different ccache performance on Linux vs OSX
As a poorly-informed guess, maybe the OS X build is turning on pre-compiled headers in a way ccache 2.4 can't cope well with? -- Martin ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
Re: [ccache] Radically different ccache performance on Linux vs OSX
On 2010-09-14 21:43, Christopher Tate wrote: > [...] > Right now I'm doing some tests around using the new > CCACHE_SLOPPINESS=file_macro tweak, and initial results are > promising... but that begs the question of why the results on OSX with > 2.4 are so poor in general. > > The obvious guess is that there's *something* about our cross-build > chain and environment that differs from the Linux-hosted versions just > enough to be upsetting ccache. Any tips on what I should go looking > for? My guess is that some include file in the OSX toolchain contains a __FILE__ or __TIME__ macro that gets expanded (and kept). This would explain the cache misses for both ccache 2.4 and 3.0. You should be able to find the difference by comparing the preprocessor output of two identical compilation commands. That is, given that you compile with something like gcc ...options... -c file.c -o file.o you could do this: gcc ...options... -E file.c -o file1.i gcc ...options... -E file.c -o file2.i diff file1.i file2.i If the culprit is a __FILE__ or __TIME__, you could consider patching the toolchain, or you could set CCACHE_SLOPPINESS as you mention. (But setting CCACHE_SLOPPINESS only affects direct mode, so preprocessor mode will still miss.) -- Joel ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
[ccache] Radically different ccache performance on Linux vs OSX
We have a large cross-compilation environment that is essentially identical on both Linux and MacOS X hosts. The build system uses ccache to try to reduce redundant recompilation, but we're seeing radically different outcomes on OSX versus Linux hosts. We're still using ccache 2.4. On Linux hosts, the aggregate performance seems to be roughly a 3:1 cache hit-to-miss ratio. However, on OSX, ccache seems to be providing almost no benefit: we see something like a 1:15 cache hit-to-miss ratio -- at which point we might as well not be using ccache at all. I've been looking into this a bit with 3.0 (actually tip of tree) on OSX. Using ccache 3 [in its default mode of direct mode then fallback to preprocessor], 90%+ of the misses that I see in the log are failure to find the manifest file at all, and I'm seeing a similar very low hit rate overall. Right now I'm doing some tests around using the new CCACHE_SLOPPINESS=file_macro tweak, and initial results are promising... but that begs the question of why the results on OSX with 2.4 are so poor in general. The obvious guess is that there's *something* about our cross-build chain and environment that differs from the Linux-hosted versions just enough to be upsetting ccache. Any tips on what I should go looking for? Thanks! -- chris tate android framework engineer ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
Re: [ccache] ccache and Sun Studio
On Tue, Sep 14, 2010 at 5:20 PM, Joel Rosdahl wrote: > I didn't know about this specific clash, but there are others very > similar described in this bug report: > > https://bugzilla.samba.org/show_bug.cgi?id=7556 > > You can create a new bug report if you want, or just leave a comment in > 7556. Thanks a lot, I added a comment to that bug. m. ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
Re: [ccache] ccache and Sun Studio
On 2010-09-14 12:23, Mehturt wrote: > I tried to use ccache 3.0.1 with Sun's Studio 12 compiler. > It seems to work just fine, except for some -x parameters that the > compiler has, such as -xarch, -xtarget etc.. > The ccache thinks of the -x parameter as the language setting, which > works only for gcc. A possible workaround is to add --ccache-skip before each troublesome parameter. Or rather: It should have been possible, but it's buggy in 3.0.1. It will be fixed in 3.1. > So is ccache supposed to work with Sun's Studio 12? Should I create a > bug report for this? I didn't know about this specific clash, but there are others very similar described in this bug report: https://bugzilla.samba.org/show_bug.cgi?id=7556 You can create a new bug report if you want, or just leave a comment in 7556. As noted in a comment to the bug report, I think that a good way to handle this is to make ccache perform compiler detection (and cache the results of it) so that it knows to (in this case) leave -xarch and friends alone. I guess it's also feasible to introduce a ccache setting that let's you select which kind of compiler you have, but it would be nicer to handle it transparently. -- Joel ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
[ccache] ccache and Sun Studio
Hi, I tried to use ccache 3.0.1 with Sun's Studio 12 compiler. It seems to work just fine, except for some -x parameters that the compiler has, such as -xarch, -xtarget etc.. The ccache thinks of the -x parameter as the language setting, which works only for gcc. So is ccache supposed to work with Sun's Studio 12? Should I create a bug report for this? Thanks.. m. ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
