runtime: tests have gotten slower

[josharian]

I've noticed running all.bash recently that the runtime tests are really slow and CPU intensive.

On my M1, I tried doing cd $GOROOT/runtime; go test -c; ./runtime.test -test.short with recent Go versions. The runtime tests now take almost 3x longer than 1.17.

• Go 1.16: 6.46 real 7.76 user 2.52 sys
• Go 1.17: 7.39 real 8.40 user 2.48 sys
• Tip, Oct 4 '21 (9432320): 20.03 real 25.64 user 6.26 sys

The slowest at tip are:

0.50s TestCgoCrashHandler
0.58s TestCgoExternalThreadSignal
0.67s TestCgoSignalDeadlock
0.71s TestCheckPtr2
0.72s TestCgoExternalThreadSIGPROF
0.77s TestEINTR
1.00s TestCheckPtr/CheckPtrAlignmentNilPtr
1.00s TestDeferKeepAlive
1.01s TestSpuriousWakeupsNeverHangSemasleep
1.13s TestVDSO
1.38s TestCgoCCodeSIGPROF

Perhaps some of these could be shortened, skipped, or marked parallel?

[cuonglm]

Maybe related #48496

[josharian]

Ouch. Yes, quite possibly!

[mknyszek]

@josharian #48496 seems to have been resolved. Is this any better?

[josharian]

It is marginally better, but still much slower than previous releases.

• 1.17: 7.58 real 9.83 user 2.84 sys
• tip (f659183): 18.80 real 26.15 user 7.19 sys

Also, tip now contains log spam:

step 1
step 8
step 9
step 10
step 11
step 12
step 13
step 14
PASS

[josharian]

Mailed CL 364555 for the log spam.

[gopherbot]

Change https://golang.org/cl/366256 mentions this issue: runtime: execute TestSpuriousWakeupsNeverHangSemasleep in parallel

[odeke-em]

How are we doing here @josharian?

[josharian]

Looks fixed.