idle GC causes large CPU usage if run more frequently than 1 second
|Reported by:||JeremyShaw||Owned by:||simonmar|
|Type of failure:||Test Case:|
|Related Tickets:||Differential Rev(s):|
I have a web server which exhibits unusual CPU usage. When it first starts it loads a bunch of state from disk -- around 800MB. It then sits idle consuming no CPU. If I make any request to the server, it starts using 30-60% of the CPU and never goes back down -- even if the request does not interact with the state system at all.
If I disable idle GC, then the problem goes away. If I set idle GC time using, +RTS -I1, the problem goes away. If I set it to, +RTS -I0.9999999, then I see the CPU usage issue.
Setting the +RTS -I1 option is sufficient for now, but the documentation says I should report any weirdness.
I do not have a simple test case for this.
Change History (6)
comment:1 Changed 7 years ago by simonmar
- difficulty set to Unknown
- Milestone set to 6.12 branch
- Owner set to simonmar
comment:4 Changed 7 years ago by simonmar
- Milestone changed from 6.12 branch to 6.12.1
- Priority changed from normal to high