X zodb/cache: Performing GC in separate goroutine was actually a bad idea (0e2be3b3) · Commits · Levin Zimmermann / neoppod

Commit 0e2be3b3 authored Jan 08, 2018 by

Kirill Smelkov

X zodb/cache: Performing GC in separate goroutine was actually a bad idea

Probably channel signalling + goroutine scheduling overhead was taking
too much - see appendix for timings.

Once again - as in 521d3ae5 (X zodb/cache: Also free OCE entries on GC)
we can ignore *Hit/size=0 increase as /size=0 won't happen in practice
and we mostly care about NoHit overhead for which /size=0 also improves.
The HitProc/* increase, as in 521d3ae5, is also withing noise.

---- 8< ----

name old time/op new time/op delta
NoopStorage 56.6ns ± 0% 57.9ns ± 1% +2.36% (p=0.100 n=3+3)
NoopStorage-4 56.9ns ± 1% 57.4ns ± 1% ~ (p=0.200 n=3+3)
CacheStartup 1.97µs ± 3% 2.13µs ±16% ~ (p=0.600 n=3+3)
CacheStartup-4 1.29µs ± 4% 1.29µs ± 4% ~ (p=1.000 n=3+3)
CacheNoHit/size=0 1.34µs ± 1% 0.68µs ± 1% -49.43% (p=0.100 n=3+3)
CacheNoHit/size=0-4 941ns ± 1% 664ns ± 1% -29.38% (p=0.100 n=3+3)
CacheNoHit/size=16 1.38µs ± 3% 0.79µs ± 0% -42.49% (p=0.100 n=3+3)
CacheNoHit/size=16-4 939ns ± 2% 788ns ± 0% -16.02% (p=0.100 n=3+3)
CacheNoHit/size=128 1.32µs ± 2% 0.80µs ± 0% -39.55% (p=0.100 n=3+3)
CacheNoHit/size=128-4 946ns ± 1% 795ns ± 1% -16.03% (p=0.100 n=3+3)
CacheNoHit/size=512 1.37µs ± 3% 0.82µs ± 0% -40.33% (p=0.100 n=3+3)
CacheNoHit/size=512-4 977ns ± 2% 803ns ± 0% -17.75% (p=0.100 n=3+3)
CacheNoHit/size=4096 1.37µs ± 4% 1.05µs ± 1% -23.03% (p=0.100 n=3+3)
CacheNoHit/size=4096-4 1.07µs ± 0% 0.86µs ± 0% -19.94% (p=0.100 n=3+3)
CacheHit/size=0 164ns ±29% 664ns ± 0% +305.08% (p=0.100 n=3+3)
CacheHit/size=0-4 251ns ± 6% 660ns ± 0% +162.95% (p=0.100 n=3+3)
CacheHit/size=16 120ns ± 1% 123ns ± 4% ~ (p=0.700 n=3+3)
CacheHit/size=16-4 121ns ± 2% 121ns ± 1% ~ (p=1.000 n=3+3)
CacheHit/size=128 123ns ± 1% 124ns ± 1% ~ (p=1.000 n=3+3)
CacheHit/size=128-4 124ns ± 0% 124ns ± 1% ~ (p=1.000 n=3+3)
CacheHit/size=512 125ns ± 0% 126ns ± 1% ~ (p=0.400 n=3+3)
CacheHit/size=512-4 126ns ± 1% 125ns ± 1% ~ (p=0.400 n=3+3)
CacheHit/size=4096 128ns ± 1% 127ns ± 1% ~ (p=1.000 n=3+3)
CacheHit/size=4096-4 128ns ± 1% 128ns ± 1% ~ (p=1.000 n=3+3)
NoopStoragePar 56.5ns ± 0% 59.2ns ± 1% +4.84% (p=0.100 n=3+3)
NoopStoragePar-4 33.1ns ± 3% 31.2ns ± 8% ~ (p=0.400 n=3+3)
CacheStartupPar 2.01µs ±14% 2.04µs ± 6% ~ (p=0.800 n=3+3)
CacheStartupPar-4 1.47µs ± 4% 1.48µs ± 3% ~ (p=1.000 n=3+3)
CacheNoHitPar/size=0 1.35µs ± 3% 0.67µs ± 0% -50.25% (p=0.100 n=3+3)
CacheNoHitPar/size=0-4 1.04µs ± 0% 0.90µs ± 0% -12.83% (p=0.100 n=3+3)
CacheNoHitPar/size=16 1.32µs ± 2% 0.79µs ± 0% -40.36% (p=0.100 n=3+3)
CacheNoHitPar/size=16-4 1.04µs ± 0% 1.03µs ± 0% -1.28% (p=0.100 n=3+3)
CacheNoHitPar/size=128 1.33µs ± 1% 0.80µs ± 0% -40.02% (p=0.100 n=3+3)
CacheNoHitPar/size=128-4 1.03µs ± 1% 1.04µs ± 0% ~ (p=0.400 n=3+3)
CacheNoHitPar/size=512 1.34µs ± 2% 0.82µs ± 0% -38.79% (p=0.100 n=3+3)
CacheNoHitPar/size=512-4 1.07µs ± 2% 1.07µs ± 0% ~ (p=0.600 n=3+3)
CacheNoHitPar/size=4096 1.36µs ± 4% 1.06µs ± 1% -21.87% (p=0.100 n=3+3)
CacheNoHitPar/size=4096-4 1.16µs ± 2% 1.17µs ± 1% ~ (p=0.700 n=3+3)
CacheHitPar/size=0 163ns ± 3% 665ns ± 0% +306.94% (p=0.100 n=3+3)
CacheHitPar/size=0-4 394ns ± 3% 903ns ± 1% +129.08% (p=0.100 n=3+3)
CacheHitPar/size=16 121ns ± 0% 124ns ± 1% +2.20% (p=0.100 n=3+3)
CacheHitPar/size=16-4 213ns ± 0% 217ns ± 1% +2.03% (p=0.100 n=3+3)
CacheHitPar/size=128 124ns ± 1% 125ns ± 0% ~ (p=0.400 n=3+3)
CacheHitPar/size=128-4 208ns ± 0% 215ns ± 1% +3.21% (p=0.100 n=3+3)
CacheHitPar/size=512 126ns ± 1% 127ns ± 1% ~ (p=0.300 n=3+3)
CacheHitPar/size=512-4 205ns ± 0% 241ns ± 0% +17.40% (p=0.100 n=3+3)
CacheHitPar/size=4096 127ns ± 0% 129ns ± 0% +1.57% (p=0.100 n=3+3)
CacheHitPar/size=4096-4 201ns ± 0% 236ns ± 4% +17.58% (p=0.100 n=3+3)
NoopStorageProc 54.8ns ± 0% 56.1ns ± 0% +2.43% (p=0.100 n=3+3)
NoopStorageProc-4 32.6ns ± 4% 37.1ns ±10% +14.02% (p=0.100 n=3+3)
CacheStartupProc 1.91µs ± 7% 1.79µs ± 3% ~ (p=0.400 n=3+3)
CacheStartupProc-4 1.13µs ± 1% 1.08µs ± 7% ~ (p=0.400 n=3+3)
CacheNoHitProc/size=0 1.32µs ± 1% 0.67µs ± 0% -49.38% (p=0.100 n=3+3)
CacheNoHitProc/size=0-4 649ns ± 1% 414ns ±15% -36.23% (p=0.100 n=3+3)
CacheNoHitProc/size=16 1.33µs ± 3% 0.79µs ± 0% -40.23% (p=0.100 n=3+3)
CacheNoHitProc/size=16-4 650ns ± 2% 440ns ± 7% -32.34% (p=0.100 n=3+3)
CacheNoHitProc/size=128 1.31µs ± 5% 0.81µs ± 0% -38.41% (p=0.100 n=3+3)
CacheNoHitProc/size=128-4 663ns ± 1% 467ns ± 8% -29.58% (p=0.100 n=3+3)
CacheNoHitProc/size=512 1.30µs ± 2% 0.83µs ± 1% -35.72% (p=0.100 n=3+3)
CacheNoHitProc/size=512-4 685ns ± 1% 499ns ± 9% -27.12% (p=0.100 n=3+3)
CacheNoHitProc/size=4096 1.35µs ± 3% 1.07µs ± 0% -20.87% (p=0.100 n=3+3)
CacheNoHitProc/size=4096-4 684ns ± 2% 629ns ± 3% -8.04% (p=0.100 n=3+3)
CacheHitProc/size=0 159ns ± 3% 669ns ± 0% +320.75% (p=0.100 n=3+3)
CacheHitProc/size=0-4 75.1ns ±10% 381.0ns ± 2% +407.10% (p=0.100 n=3+3)
CacheHitProc/size=16 120ns ± 1% 121ns ± 1% ~ (p=0.300 n=3+3)
CacheHitProc/size=16-4 58.1ns ± 2% 65.0ns ± 3% +11.94% (p=0.100 n=3+3)
CacheHitProc/size=128 123ns ± 0% 124ns ± 0% +0.81% (p=0.100 n=3+3)
CacheHitProc/size=128-4 57.6ns ± 0% 74.9ns ± 3% +30.05% (p=0.100 n=3+3)
CacheHitProc/size=512 124ns ± 1% 125ns ± 1% ~ (p=0.300 n=3+3)
CacheHitProc/size=512-4 59.4ns ± 1% 71.5ns ± 2% +20.38% (p=0.100 n=3+3)
CacheHitProc/size=4096 127ns ± 0% 132ns ± 6% +3.94% (p=0.100 n=3+3)
CacheHitProc/size=4096-4 64.2ns ± 1% 80.5ns ± 7% +25.34% (p=0.100 n=3+3)

name old alloc/op new alloc/op delta
NoopStorage 0.00B 0.00B ~ (all equal)
NoopStorage-4 0.00B 0.00B ~ (all equal)
CacheStartup 285B ± 0% 285B ± 0% ~ (all equal)
CacheStartup-4 285B ± 0% 285B ± 0% ~ (all equal)
CacheNoHit/size=0 247B ± 2% 152B ± 0% -38.38% (p=0.100 n=3+3)
CacheNoHit/size=0-4 153B ± 0% 152B ± 0% -0.65% (p=0.100 n=3+3)
CacheNoHit/size=16 247B ± 2% 153B ± 0% -37.97% (p=0.100 n=3+3)
CacheNoHit/size=16-4 153B ± 0% 153B ± 0% ~ (p=1.000 n=3+3)
CacheNoHit/size=128 241B ± 1% 153B ± 0% -36.60% (p=0.100 n=3+3)
CacheNoHit/size=128-4 153B ± 0% 153B ± 0% ~ (p=1.000 n=3+3)
CacheNoHit/size=512 245B ± 1% 153B ± 0% -37.64% (p=0.100 n=3+3)
CacheNoHit/size=512-4 154B ± 0% 153B ± 0% -0.65% (p=0.100 n=3+3)
CacheNoHit/size=4096 244B ± 1% 153B ± 0% -37.21% (p=0.100 n=3+3)
CacheNoHit/size=4096-4 155B ± 0% 152B ± 0% -1.72% (p=0.100 n=3+3)
CacheHit/size=0 5.00B ±100% 152.00B ± 0% +2940.00% (p=0.100 n=3+3)
CacheHit/size=0-4 11.0B ± 9% 152.0B ± 0% +1281.82% (p=0.100 n=3+3)
CacheHit/size=16 0.00B 0.00B ~ (all equal)
CacheHit/size=16-4 0.00B 0.00B ~ (all equal)
CacheHit/size=128 0.00B 0.00B ~ (all equal)
CacheHit/size=128-4 0.00B 0.00B ~ (all equal)
CacheHit/size=512 0.00B 0.00B ~ (all equal)
CacheHit/size=512-4 0.00B 0.00B ~ (all equal)
CacheHit/size=4096 0.00B 0.00B ~ (all equal)
CacheHit/size=4096-4 0.00B 0.00B ~ (all equal)
NoopStoragePar 0.00B 0.00B ~ (all equal)
NoopStoragePar-4 0.00B 0.00B ~ (all equal)
CacheStartupPar 285B ± 0% 285B ± 0% ~ (all equal)
CacheStartupPar-4 282B ± 1% 281B ± 0% ~ (p=0.600 n=3+3)
CacheNoHitPar/size=0 247B ± 2% 152B ± 0% -38.38% (p=0.100 n=3+3)
CacheNoHitPar/size=0-4 161B ± 0% 152B ± 0% -5.59% (p=0.100 n=3+3)
CacheNoHitPar/size=16 245B ± 1% 153B ± 0% -37.55% (p=0.100 n=3+3)
CacheNoHitPar/size=16-4 161B ± 0% 155B ± 0% -3.93% (p=0.100 n=3+3)
CacheNoHitPar/size=128 245B ± 2% 153B ± 0% -37.55% (p=0.100 n=3+3)
CacheNoHitPar/size=128-4 162B ± 0% 153B ± 0% -5.36% (p=0.100 n=3+3)
CacheNoHitPar/size=512 246B ± 3% 153B ± 0% -37.89% (p=0.100 n=3+3)
CacheNoHitPar/size=512-4 161B ± 0% 153B ± 0% -4.97% (p=0.100 n=3+3)
CacheNoHitPar/size=4096 244B ± 3% 153B ± 0% -37.38% (p=0.100 n=3+3)
CacheNoHitPar/size=4096-4 164B ± 0% 153B ± 0% -6.71% (p=0.100 n=3+3)
CacheHitPar/size=0 5.00B ±20% 152.00B ± 0% +2940.00% (p=0.100 n=3+3)
CacheHitPar/size=0-4 14.0B ± 7% 152.0B ± 0% +985.71% (p=0.100 n=3+3)
CacheHitPar/size=16 0.00B 0.00B ~ (all equal)
CacheHitPar/size=16-4 0.00B 0.00B ~ (all equal)
CacheHitPar/size=128 0.00B 0.00B ~ (all equal)
CacheHitPar/size=128-4 0.00B 0.00B ~ (all equal)
CacheHitPar/size=512 0.00B 0.00B ~ (all equal)
CacheHitPar/size=512-4 0.00B 0.00B ~ (all equal)
CacheHitPar/size=4096 0.00B 0.00B ~ (all equal)
CacheHitPar/size=4096-4 0.00B 0.00B ~ (all equal)
NoopStorageProc 0.00B 0.00B ~ (all equal)
NoopStorageProc-4 0.00B 0.00B ~ (all equal)
CacheStartupProc 285B ± 0% 285B ± 0% ~ (all equal)
CacheStartupProc-4 285B ± 0% 285B ± 0% ~ (all equal)
CacheNoHitProc/size=0 243B ± 1% 152B ± 0% -37.53% (p=0.100 n=3+3)
CacheNoHitProc/size=0-4 195B ± 1% 152B ± 0% -22.05% (p=0.100 n=3+3)
CacheNoHitProc/size=16 247B ± 2% 153B ± 0% -37.97% (p=0.100 n=3+3)
CacheNoHitProc/size=16-4 194B ± 0% 153B ± 0% -21.27% (p=0.100 n=3+3)
CacheNoHitProc/size=128 242B ± 4% 153B ± 0% -36.78% (p=0.100 n=3+3)
CacheNoHitProc/size=128-4 193B ± 0% 153B ± 0% -20.86% (p=0.100 n=3+3)
CacheNoHitProc/size=512 240B ± 2% 153B ± 0% -36.48% (p=0.100 n=3+3)
CacheNoHitProc/size=512-4 190B ± 1% 153B ± 0% -19.33% (p=0.100 n=3+3)
CacheNoHitProc/size=4096 245B ± 2% 153B ± 0% -37.55% (p=0.100 n=3+3)
CacheNoHitProc/size=4096-4 181B ± 2% 153B ± 0% -15.47% (p=0.100 n=3+3)
CacheHitProc/size=0 4.33B ±15% 152.00B ± 0% +3407.69% (p=0.100 n=3+3)
CacheHitProc/size=0-4 3.33B ±50% 152.00B ± 0% +4460.00% (p=0.100 n=3+3)
CacheHitProc/size=16 0.00B 0.00B ~ (all equal)
CacheHitProc/size=16-4 0.00B 0.00B ~ (all equal)
CacheHitProc/size=128 0.00B 0.00B ~ (all equal)
CacheHitProc/size=128-4 0.00B 0.00B ~ (all equal)
CacheHitProc/size=512 0.00B 0.00B ~ (all equal)
CacheHitProc/size=512-4 0.00B 0.00B ~ (all equal)
CacheHitProc/size=4096 0.00B 0.00B ~ (all equal)
CacheHitProc/size=4096-4 0.00B 0.00B ~ (all equal)

name old allocs/op new allocs/op delta
NoopStorage 0.00 0.00 ~ (all equal)
NoopStorage-4 0.00 0.00 ~ (all equal)
CacheStartup 5.00 ± 0% 5.00 ± 0% ~ (all equal)
CacheStartup-4 5.00 ± 0% 5.00 ± 0% ~ (all equal)
CacheNoHit/size=0 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=0-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=16 3.33 ±20% 3.00 ± 0% ~ (p=1.000 n=3+3)
CacheNoHit/size=16-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=128 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=128-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=512 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=512-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=4096 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHit/size=4096-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheHit/size=0 0.00 3.00 ± 0% +Inf% (p=0.100 n=3+3)
CacheHit/size=0-4 0.00 3.00 ± 0% +Inf% (p=0.100 n=3+3)
CacheHit/size=16 0.00 0.00 ~ (all equal)
CacheHit/size=16-4 0.00 0.00 ~ (all equal)
CacheHit/size=128 0.00 0.00 ~ (all equal)
CacheHit/size=128-4 0.00 0.00 ~ (all equal)
CacheHit/size=512 0.00 0.00 ~ (all equal)
CacheHit/size=512-4 0.00 0.00 ~ (all equal)
CacheHit/size=4096 0.00 0.00 ~ (all equal)
CacheHit/size=4096-4 0.00 0.00 ~ (all equal)
NoopStoragePar 0.00 0.00 ~ (all equal)
NoopStoragePar-4 0.00 0.00 ~ (all equal)
CacheStartupPar 5.00 ± 0% 5.00 ± 0% ~ (all equal)
CacheStartupPar-4 4.33 ±15% 4.00 ± 0% ~ (p=1.000 n=3+3)
CacheNoHitPar/size=0 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=0-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=16 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=16-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=128 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=128-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=512 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=512-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=4096 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitPar/size=4096-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheHitPar/size=0 0.00 3.00 ± 0% +Inf% (p=0.100 n=3+3)
CacheHitPar/size=0-4 0.00 3.00 ± 0% +Inf% (p=0.100 n=3+3)
CacheHitPar/size=16 0.00 0.00 ~ (all equal)
CacheHitPar/size=16-4 0.00 0.00 ~ (all equal)
CacheHitPar/size=128 0.00 0.00 ~ (all equal)
CacheHitPar/size=128-4 0.00 0.00 ~ (all equal)
CacheHitPar/size=512 0.00 0.00 ~ (all equal)
CacheHitPar/size=512-4 0.00 0.00 ~ (all equal)
CacheHitPar/size=4096 0.00 0.00 ~ (all equal)
CacheHitPar/size=4096-4 0.00 0.00 ~ (all equal)
NoopStorageProc 0.00 0.00 ~ (all equal)
NoopStorageProc-4 0.00 0.00 ~ (all equal)
CacheStartupProc 5.00 ± 0% 5.00 ± 0% ~ (all equal)
CacheStartupProc-4 5.00 ± 0% 5.00 ± 0% ~ (all equal)
CacheNoHitProc/size=0 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=0-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=16 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=16-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=128 3.33 ±20% 3.00 ± 0% ~ (p=1.000 n=3+3)
CacheNoHitProc/size=128-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=512 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=512-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheNoHitProc/size=4096 3.33 ±20% 3.00 ± 0% ~ (p=1.000 n=3+3)
CacheNoHitProc/size=4096-4 3.00 ± 0% 3.00 ± 0% ~ (all equal)
CacheHitProc/size=0 0.00 3.00 ± 0% +Inf% (p=0.100 n=3+3)
CacheHitProc/size=0-4 0.00 3.00 ± 0% +Inf% (p=0.100 n=3+3)
CacheHitProc/size=16 0.00 0.00 ~ (all equal)
CacheHitProc/size=16-4 0.00 0.00 ~ (all equal)
CacheHitProc/size=128 0.00 0.00 ~ (all equal)
CacheHitProc/size=128-4 0.00 0.00 ~ (all equal)
CacheHitProc/size=512 0.00 0.00 ~ (all equal)
CacheHitProc/size=512-4 0.00 0.00 ~ (all equal)
CacheHitProc/size=4096 0.00 0.00 ~ (all equal)
CacheHitProc/size=4096-4 0.00 0.00 ~ (all equal)

parent a5d0e83f

Hide whitespace changes

Inline Side-by-side

View file @ 0e2be3b3

@@ -47,9 +47,6 @@ type Cache struct {
 	entryMap map[Oid]*oidCacheEntry	// oid -> oid's cache entries
 	// garbage collection:
 	gcCh chan struct{} // signals gc to run
 	gcMu sync.Mutex
 	lru  lruHead	// revCacheEntries in LRU order
 	size int	// cached data size in bytes
@@ -129,34 +126,20 @@ func NewCache(loader StorLoader, sizeMax int) *Cache {
 	c := &Cache{
 		loader:   loader,
 		entryMap: make(map[Oid]*oidCacheEntry),
 		gcCh:     make(chan struct{}, 1), // 1 is important - see gcsignal
 		sizeMax:  sizeMax,
+	}
 	c.lru.Init()
 	go c.gcmain()
 	return c
+}
 // SetSizeMax adjusts how much RAM cache can use for cached data.
 func (c *Cache) SetSizeMax(sizeMax int) {
 	gcrun := false
 	c.gcMu.Lock()
 	c.sizeMax = sizeMax
 	if c.size > c.sizeMax {
 		gcrun = true
 		c.gc()
+	}
 	c.gcMu.Unlock()
 	if gcrun {
 		c.gcsignal()
+	}
+}
 // Close stops cache operation. It is illegal to use cache in any way after call to Close.
 // XXX temp - will be gone
 func (c *Cache) Close() {
 	close(c.gcCh)
+}
 // Load loads data from database via cache.
@@ -403,7 +386,6 @@ func (c *Cache) loadRCE(ctx context.Context, rce *revCacheEntry) {
 	// update lru & cache size
 	gcrun := false
 	c.gcMu.Lock()
 	if rcePrevDropped != nil {
@@ -414,13 +396,10 @@ func (c *Cache) loadRCE(ctx context.Context, rce *revCacheEntry) {
+	}
 	c.size += δsize
 	if c.size > c.sizeMax {
 		gcrun = true
 		c.gc()
+	}
 	c.gcMu.Unlock()
 	if gcrun {
 		c.gcsignal()
+	}
+}
 // tryMerge tries to merge rce prev into next
@@ -486,38 +465,12 @@ func tryMerge(prev, next, cur *revCacheEntry) bool {
 // ---- garbage collection ----
 // gcsignal tells cache gc to run
 func (c *Cache) gcsignal() {
 	select {
 	case c.gcCh <- struct{}{}:
 		// ok
 	default:
 		// also ok - .gcCh is created with size 1 so if we could not
 		// put something to it - there is already 1 element in there
 		// and so gc will get signal to run.
+	}
+}
 // gcmain is the process that cleans cache by evicting less-needed entries.
 func (c *Cache) gcmain() {
 	for {
 		select {
 		case _, ok := <-c.gcCh:
 			// end of operation
 			if !ok {
 				return
+			}
 			// someone asks us to run GC
 			c.gc()
+		}
+	}
+}
 //trace:event traceCacheGCStart(c *Cache)
 //trace:event traceCacheGCFinish(c *Cache)
 // gc performs garbage-collection
 // gc performs garbage-collection.
 //
 // must be called with .gcMu locked.
 func (c *Cache) gc() {
 	traceCacheGCStart(c)
 	defer traceCacheGCFinish(c)
@@ -525,9 +478,7 @@ func (c *Cache) gc() {
 	//defer fmt.Printf("< gc\n")
 	for {
 		c.gcMu.Lock()
 		if c.size <= c.sizeMax {
 			c.gcMu.Unlock()
 			return
+		}
@@ -562,7 +513,6 @@ func (c *Cache) gc() {
 		oce.Unlock()
 		h.Delete()
 		c.gcMu.Unlock()
 		if oceFree {
 			c.mu.Lock()
-...

View file @ 0e2be3b3

@@ -584,7 +584,7 @@ func TestCache(t *testing.T) {
 	// and still loading works (because even if though rce's are evicted
 	// they stay live while someone user waits and uses it)
 	checkLoad(xidat(1,4), b(hello), 4, nil)
 	go checkLoad(xidat(1,4), b(hello), 4, nil)
 	tc.Expect(gcstart, gcfinish)
 	checkOIDV()
 	checkMRU(0)
@@ -703,7 +703,6 @@ func benchEachCache(b *testing.B, f func(b *testing.B, c *Cache)) {
 		b.Run(fmt.Sprintf("size=%d", size), func(b *testing.B) {
 			c := NewCache(s, size)
 			f(b, c)
 			c.Close()
 		})
+	}
+}
@@ -714,7 +713,6 @@ func BenchmarkCacheStartup(b *testing.B) {
 	c := NewCache(s, b.N)
 	benchLoad(b, c, b.N)
 	b.StopTimer()
 	c.Close()
+}
 // Serially benchmark cache overhead - the additional time cache adds for loading not-yet-cached entries.
@@ -770,7 +768,6 @@ func BenchmarkCacheStartupPar(b *testing.B) {
 	c := NewCache(s, b.N)
 	benchLoadPar(b, c, b.N)
 	b.StopTimer()
 	c.Close()
+}
 func BenchmarkCacheNoHitPar(b *testing.B) {
@@ -833,7 +830,6 @@ func BenchmarkCacheStartupProc(b *testing.B) {
 			b.Fatal(err)
+		}
 		// XXX stop timer
 		c.Close()
 	})
+}
@@ -844,7 +840,6 @@ func benchEachCacheProc(b *testing.B, f func(b *testing.B, pb *testing.PB, c *Ca
 				s := &noopStorage{}
 				c := NewCache(s, size)
 				err := f(b, pb, c)
 				c.Close()
 				if err != nil {
 					b.Fatal(err)
+				}
-...

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