Re: ccache

From: Bakul Shah <>
Date: Tue, 04 Apr 2023 02:41:47 UTC

> On Apr 3, 2023, at 6:48 PM, Craig Leres <> wrote:
> On 4/3/23 17:09, Bakul Shah wrote:
>> Am I use ccache incorrectly or is there a bug?
>> # CCACHE_DIR=/usr/obj/ccache ccache -s
>> cache directory                     /usr/obj/ccache
>> primary config                      /usr/obj/ccache/ccache.conf
>> secondary config      (readonly)    /usr/local/etc/ccache.conf
>> stats updated                       Mon Apr  3 16:54:31 2023
>> ...
>> cleanups performed                   507
>> files in cache                   2795230
>> cache size                           2.9 GB <===
>> max cache size                      15.0 GB
>> # find /usr/obj/ccache -type f |wc
>>  2795395 2795395 142222206
>> # du -sh /usr/obj/ccache
>>  83G    /usr/obj/ccache <===
>> I have
>> CCACHE_DIR=/usr/obj/ccache
>> in /etc/make.conf
> Thank you for bringing this up; I have the same issue and have never figured it out. But I think I've found another piece or two of the puzzle.
> Using my favorite ktrace trick we can see that by default it tries to open /usr/local/etc/ccache.conf:
>    zinc 32 % cd /tmp && ktrace -di ccache -s > /dev/null
>    zinc 33 % kdump | fgrep NAMI | fgrep ccache.conf
>     17418 ccache   NAMI  "/usr/local/etc/ccache.conf"
>  17418 ccache   NAMI  "/home/zinc/u0/leres/.ccache/ccache.conf"
> I suspect the trick here is when ccache runs inside a poudriere jail, ccache.conf is not present and/or not in the right location.

I checked that it uses the correct ccache.conf and ccache dir.

> On my build server I have /var/cache/ccache/ccache.conf which I believe works for some things but I still have 46 GB in /var/cache/ccache and /var/cache/ccache/ccache.conf is trying to limit use to 8 GB.
> If I start up a poudriere jail and look around I find /root/.ccache/ccache.conf is a copy of /var/cache/ccache/ccache.conf. So I don't get why it doesn't work.
> (Now I'll sit back and wait for something who knows more chimes in...)
> Craig

I did the same thing this time as before -- I manually ran
"ccache -c".

Even now the number it reports is smaller by a few G than
what du -sh reveals, and it says there are many more files
in the cache than find reveals.

I suspect it either doesn't do proper bookkeeping or gets
confused if you ^Ced a build at the wrong time. It does
seem to update $CCACHE_DIR/?/stats files.

ccache -c took a very long time. ktrace shows it does
the equivalent of 
for each file f to be deleted
  rename $f $f.ccache.rm.tmp
  unlink $f.ccache.rm.tmp

Not sure why the rename is needed.