[Libreoffice] ccache support

[Terrence Enger]

On Tue, 2011-08-09 at 21:33 +0200, Christian Lohmaier wrote:
> Hi *,
> 
> On Tue, Aug 9, 2011 at 8:58 PM, Terrence Enger <tenger at iseries-guru.com> wrote:
> > On Mon, 2011-08-08 at 11:40 +0200, Christian Lohmaier wrote:
> >>
> >> Not true either. Default ccache size is 1GB, and that is enough when
> >> you focus on one branch. (a build uses less than 500MB)
> >
> > Just a note about what I have observed, for anybody who
> > happens to care.
> >
> >
> >    cache directory                     /home/terry/.ccache
> >    cache hit (direct)                  6158
> >    cache hit (preprocessed)              37
> >    cache miss                         11986
> > [...]
> >    files in cache                     30789
> >    cache size                           4.1 Gbytes
> >    max cache size                      10.0 Gbytes
> >
> > This makes me really glad that I set a max cache size larger
> > than the default 1 GB,
> 
> So you showed some irrelevant numbers, at least for the current topic.
> Your cache is filled with other stuff already, not with just the files
> from one single build.
> And of course ccache will happily use whatever size is available
> before it starts to expire old files.

Actually, my cache was empty when I started just after
midnight ...

    cache directory                     /home/terry/.ccache
    cache hit (direct)                     0
    cache hit (preprocessed)               0
    cache miss                             0
    files in cache                         0
    cache size                             0 Kbytes
    max cache size                       1.0 Gbytes

Then I increased the maximum size.

> 
> But yes, If you build with debug symbols, you need larger cache size.
> The <500MB for a build was referring to product builds, without any
> debugging options.
> 
> > For comparison, after I had completed several non-product
> > builds of OpenOffice, my cache statistics looked like ...
> >
> >    cache directory                     /media/2ced347d-3cdc-49f5-956d-099d36784957/terry/OOo_hacking/SRC_DIR_ccache
> >    cache hit (direct)                     0
> >    cache hit (preprocessed)           15499
> >    cache miss                         14993
> 
> That is a rather bad hit ratio - something between 5:1 and 10:1 when
> building often would be what I expect. 1:1 is when you build versions
> that did have lots of changes in between.
> And no direct hits? Did you disable it?

This is from last year.  I suspect the numbers result from
two builds, the first giving almost all misses and second
giving almost all hits.

I dunno about direct hits.  Direct hits may be a feature
newer than the ccache I was running then.

> (snip)
> >    max files                         100000
> 
> Any reason why you set a limit on the number of files?

No, I think ccache did that all on its own.  OTOH, the man
page says there is no default value for --max-files.  The
output from `script` does not contain the string
"max-files".  Sigh.


Terry.