Re: [ccache] Compression on or off by default?
On Wed, 3 Mar 2010 05:00:48 -0500
Mike Frysinger vapier@gmail.com wrote:
make the default a ./configure option that defaults to off
I would prefer not to make a build-time option of this, because then the
documentation has say something in line with whether files are compressed by
default depends on how ccache was built, which I think would be unfortunate. I
chose to not include the --{en,dis}able-zlib option from the original patch for
the same reason. I think it's better to strive for good defaults and few
build-time options.
-- Joel
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Re: [ccache] Compression on or off by default?
On Thu, Mar 4, 2010 at 16:00, Joel Rosdahl wrote:
On Wed, 3 Mar 2010 05:00:48 -0500 Mike Frysinger wrote:
make the default a ./configure option that defaults to off
I would prefer not to make a build-time option of this, because then the
documentation has say something in line with whether files are compressed by
default depends on how ccache was built, which I think would be unfortunate.
I
chose to not include the --{en,dis}able-zlib option from the original patch
for
the same reason. I think it's better to strive for good defaults and few
build-time options.
i didnt mean the configure option was in place of the runtime knobs
regardless, unless the compression is very low overhead, the default
should be off
-mike
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Re: [ccache] Compression on or off by default?
On Wed, 3 Mar 2010 10:39:47 + Dalton, Tom tdal...@hp.com wrote: I would say for the first release of a new feature, default it to off. That gives people a chance to 'play' with it without potentially breaking existing installations that are simply upgrading. If there are no major problems with the feature in that first release then make it a default in the next release after that (e.g. ccache-3.1). The compression feature is actually quite well-tested: it has been enabled by default in Debian's ccache packages since 2007. But I'm leaning on disabling compression by default for ccache anyway. Score so far: 4 votes (2 off-list) for default to off and 0 votes for default to on. My direct mode feature, on the other hand, is a much larger and less tested change, which I'm very well aware of. My secret plan was to try to get people to test my first announced release, and now the 3.0pre0 release, but neither release has triggered much reaction. So, maybe 3.0 will have to have direct mode disabled by default, unless I find a way to get more testers. :-) (Opinions are welcome, as usual.) -- Joel ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
Re: [ccache] Compression on or off by default?
4 mar 2010 kl. 22.30 skrev Joel Rosdahl: On Wed, 3 Mar 2010 10:39:47 + Dalton, Tom tdal...@hp.com wrote: I would say for the first release of a new feature, default it to off. That gives people a chance to 'play' with it without potentially breaking existing installations that are simply upgrading. If there are no major problems with the feature in that first release then make it a default in the next release after that (e.g. ccache-3.1). My direct mode feature, on the other hand, is a much larger and less tested change, which I'm very well aware of. My secret plan was to try to get people to test my first announced release, and now the 3.0pre0 release, but neither release has triggered much reaction. So, maybe 3.0 will have to have direct mode disabled by default, unless I find a way to get more testers. :-) (Opinions are welcome, as usual.) -- Joel Joel, we've been using the 3.0pre0 release from day one, in a setup where a dirty dozen plus some droids share a cache. All defaults, CCACHE_PREFIX=distcc. I have nothing out of the ordinary to report. Thanks for your work! Anders Furuhed Pantor Engineering AB ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
Re: [ccache] Compression on or off by default?
On Tue, Mar 2, 2010 at 17:10, Joel Rosdahl wrote: Lars Gustäbel's compression patch (which will be incorporated in ccache 3.0) enables compression by default, and if you don't want compression you have to set CCACHE_NOCOMPRESS. I'm still a bit undecided about whether defaulting to compression is a good idea, though. Maybe we should be more conservative here and require CCACHE_COMPRESS to be set to enable compression instead? (Note that the question only is about the default behaviour when storing files in the cache -- ccache will still be able to read compressed and uncompressed files from the cache regardless of the CCACHE_(NO)COMPRESS setting.) The main argument I see for making compression opt-in is that hard-linking doesn't work for compressed files (where doesn't work means that ccache will fall back to copying), so if you would like to try out hard-linking, you must set both CCACHE_NOCOMPRESS and CCACHE_HARDLINK, and also build up the cache again. Or, if you currently have enabled hard-linking with ccache 2.4, you need to take the explicit action of disabling compression after an upgrade to get the previous behaviour. Another argument is maybe that disk space is cheap nowadays, and most people probably want to optimize for speed instead of disk space. On the other hand, the overhead of using compression is very small. In fact, I am unable to consistently measure any performance impact whatsoever. (Lars Gustäbel's own measurements can be found at http://gustaebel.de/lars/ccache/.) And, by compressing the cached files, more files will fit in the cache and also in the OS disk cache. Does anyone have an opinion to share about this? make the default a ./configure option that defaults to off -mike ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
Re: [ccache] Compression on or off by default?
I would say for the first release of a new feature, default it to off. That gives people a chance to 'play' with it without potentially breaking existing installations that are simply upgrading. If there are no major problems with the feature in that first release then make it a default in the next release after that (e.g. ccache-3.1). -Original Message- From: ccache-boun...@lists.samba.org [mailto:ccache-boun...@lists.samba.org] On Behalf Of Joel Rosdahl Sent: 02 March 2010 22:11 To: ccache@lists.samba.org Subject: [ccache] Compression on or off by default? Hi, Lars Gustäbel's compression patch (which will be incorporated in ccache 3.0) enables compression by default, and if you don't want compression you have to set CCACHE_NOCOMPRESS. I'm still a bit undecided about whether defaulting to compression is a good idea, though. Maybe we should be more conservative here and require CCACHE_COMPRESS to be set to enable compression instead? (Note that the question only is about the default behaviour when storing files in the cache -- ccache will still be able to read compressed and uncompressed files from the cache regardless of the CCACHE_(NO)COMPRESS setting.) The main argument I see for making compression opt-in is that hard-linking doesn't work for compressed files (where doesn't work means that ccache will fall back to copying), so if you would like to try out hard-linking, you must set both CCACHE_NOCOMPRESS and CCACHE_HARDLINK, and also build up the cache again. Or, if you currently have enabled hard-linking with ccache 2.4, you need to take the explicit action of disabling compression after an upgrade to get the previous behaviour. Another argument is maybe that disk space is cheap nowadays, and most people probably want to optimize for speed instead of disk space. On the other hand, the overhead of using compression is very small. In fact, I am unable to consistently measure any performance impact whatsoever. (Lars Gustäbel's own measurements can be found at http://gustaebel.de/lars/ccache/.) And, by compressing the cached files, more files will fit in the cache and also in the OS disk cache. Does anyone have an opinion to share about this? -- Joel ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
[ccache] Compression on or off by default?
Hi, Lars Gustäbel's compression patch (which will be incorporated in ccache 3.0) enables compression by default, and if you don't want compression you have to set CCACHE_NOCOMPRESS. I'm still a bit undecided about whether defaulting to compression is a good idea, though. Maybe we should be more conservative here and require CCACHE_COMPRESS to be set to enable compression instead? (Note that the question only is about the default behaviour when storing files in the cache -- ccache will still be able to read compressed and uncompressed files from the cache regardless of the CCACHE_(NO)COMPRESS setting.) The main argument I see for making compression opt-in is that hard-linking doesn't work for compressed files (where doesn't work means that ccache will fall back to copying), so if you would like to try out hard-linking, you must set both CCACHE_NOCOMPRESS and CCACHE_HARDLINK, and also build up the cache again. Or, if you currently have enabled hard-linking with ccache 2.4, you need to take the explicit action of disabling compression after an upgrade to get the previous behaviour. Another argument is maybe that disk space is cheap nowadays, and most people probably want to optimize for speed instead of disk space. On the other hand, the overhead of using compression is very small. In fact, I am unable to consistently measure any performance impact whatsoever. (Lars Gustäbel's own measurements can be found at http://gustaebel.de/lars/ccache/.) And, by compressing the cached files, more files will fit in the cache and also in the OS disk cache. Does anyone have an opinion to share about this? -- Joel ___ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
