Slowdown when local fs lru cache fills up

[drahnr]

Once the server side file cache hits the limit, compilation slows down significantly.

Compile requests                     503
Compile requests executed            383
Cache hits                           359
Cache hits (C/C++)                    15
Cache hits (Rust)                    344
Cache misses                          14
Cache misses (Rust)                   14
Cache timeouts                         1
Cache read errors                      0
Forced recaches                        0
Cache write errors                     0
Compilation failures                   2
Cache errors                           0
Non-cacheable compilations             0
Non-cacheable calls                  118
Non-compilation calls                  2
Unsupported compiler calls             0
Average cache write                6.028 s <<<<<<<<
Average cache read miss           29.963 s <<<<<<<<
Average cache read hit             3.808 s <<<<<<<<
Failed distributed compilations        4

Successful distributed compiles
  XXXXXXXXXXXXXX                10

Non-cacheable reasons:
crate-type                            98
unknown source language               15
-                                      4
-E                                     1

Cache location                  Redis: XXXXXXX
Cache size                            16 GiB
Max cache size                        16 GiB