[ccache] explanation of ccache stats
Anders Björklund
anders at itension.se
Wed Mar 16 17:24:47 UTC 2016
Stéphane Charette wrote:
>> I created a new web page with some example graphs from the ccache plugins
>> in case anyone wants to see what it looks like:
>> https://www.ccoderun.ca/ccache-munin/
>
> ...and I should have mentioned, if anyone has more ideas on additional
> graphs I can extract from ccache information, let me know and I'll create
> the necessary plugins.
We are keeping the following counters:
ccache_files
ccache_size
ccache_hit_dir
ccache_hit_cpp
ccache_miss
ccache_link
ccache_total
Basically "link" is a user error, as ccache shouldn't be used for
linking. We keep it just so that it *doesn't* happen, and also:
ccache_preprocessing
ccache_unsupported
ccache_internal
These have been useful to catch for instance --coverage before
and to catch certain, ehrm, early implementation quirks. :-)
The rest of the errors are logged, but are not being counted.
And also these non-counters (constants/strings), for info:
ccache_directory
ccache_maxfiles
ccache_maxsize
What *would* be useful is a future feature to get stats for
each build, instead of only having statistics per cache ?
The workaround is to grep them out from the debugging log,
but that's a bit expensive to have enabled by default...
So adding a feature to only keep the "Result:" part of it.
(probably already counted for you, saves | sort | uniq -c)
Another coming feature is to keep *only* the stderr output.
(so that you can get the warnings and errors without grep)
/Anders
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