Re: Mingw task for Cirrus CI

Hi,

On 2022-10-11 11:23:36 -0700, Andres Freund wrote:
> > + build_script:
> > + - C:\msys64\usr\bin\dash.exe -lc "cd %CIRRUS_WORKING_DIR% && ninja -C %BUILD_DIR%"
> > + upload_caches: ccache

Only remembered that just after sending my email: When using b_pch=true (which
saves a lot of time on mingw) ccache won't cache much (IIRC just the pch files
themselves) unless you do something like
export CCACHE_SLOPPINESS=pch_defines,time_macros

$ ccache -z -C
Clearing... 100.0% [==============================================================================]

$ ninja clean && ccache -z && CCACHE_SLOPPINESS= time ninja src/bin/pg_test_fsync/pg_test_fsync.exe && ccache -s
[2/2] Cleaning
Cleaning... 200 files.
Statistics zeroed
[124/124] Linking target src/bin/pg_test_fsync/pg_test_fsync.exe
0.00user 0.01system 0:07.60elapsed 0%CPU (0avgtext+0avgdata 4936maxresident)k
0inputs+0outputs (1314major+0minor)pagefaults 0swaps
Summary:
Hits: 0 / 1 (0.00 %)
Direct: 0 / 1 (0.00 %)
Preprocessed: 0 / 1 (0.00 %)
Misses: 1
Direct: 1
Preprocessed: 1
Uncacheable: 110

As you can see, most of the files are determined to be unachable. The build
took 7.6s.

$ ninja clean && ccache -z && CCACHE_SLOPPINESS=pch_defines,time_macros time ninja src/bin/pg_test_fsync/pg_test_fsync.exe && ccache -s
[2/2] Cleaning
Cleaning... 200 files.
Statistics zeroed
[124/124] Linking target src/bin/pg_test_fsync/pg_test_fsync.exe
0.00user 0.01system 0:09.91elapsed 0%CPU (0avgtext+0avgdata 4936maxresident)k
0inputs+0outputs (1313major+0minor)pagefaults 0swaps
Summary:
Hits: 0 / 111 (0.00 %)
Direct: 0 / 111 (0.00 %)
Preprocessed: 0 / 111 (0.00 %)
Misses: 111
Direct: 111
Preprocessed: 111
Primary storage:
Hits: 0 / 216 (0.00 %)
Misses: 216
Cache size (GB): 0.05 / 5.00 (0.98 %)

Files are cachable, but are cache misses (because we cleaned the cache
above). The build took 9.91s.

$ ninja clean && ccache -z && CCACHE_SLOPPINESS=pch_defines,time_macros time ninja src/bin/pg_test_fsync/pg_test_fsync.exe && ccache -s
[2/2] Cleaning
Cleaning... 200 files.
Statistics zeroed
[124/124] Linking target src/bin/pg_test_fsync/pg_test_fsync.exe
0.00user 0.01system 0:02.40elapsed 0%CPU (0avgtext+0avgdata 4936maxresident)k
0inputs+0outputs (1314major+0minor)pagefaults 0swaps
Summary:
Hits: 111 / 111 (100.0 %)
Direct: 111 / 111 (100.0 %)
Preprocessed: 0 / 0
Misses: 0
Direct: 0
Preprocessed: 0
Primary storage:
Hits: 222 / 222 (100.0 %)
Misses: 0
Cache size (GB): 0.05 / 5.00 (0.98 %)

Files are cachable, and hit the cache. The build takes 2.4s.

Using ccache's depend mode reduce the cache-miss case to 7.51s and the cache
hit case to 1.75s. So we should likely export CCACHE_DEPEND=1 as well.

Greetings,

Andres Freund