Program in (-N1) runs 10 times slower than it with two threads (-N2)
|Reported by:||wuxb||Owned by:||simonmar|
|Operating System:||Linux||Architecture:||x86_64 (amd64)|
|Type of failure:||Runtime performance bug||Difficulty:|
|Test Case:||Blocked By:|
Initially I want to do some test on threads, I wrote this program(see below) to test the performance when two thread operates on same memory location.
but with (-N2) rts options, it works normally, but with (-N1), the CPU work load became vary low (30%~40%). it uses much more time to finish.
no -threaded : 3.7s (wall clock time)
-N2 : 4.0s (wall clock time)
-N1 : 20.0s(wall clock time)
(forkIO/FFI/MVar/Ptr are used in this program).
source code & log messages will be in attached files.
Change History (5)
Changed 3 years ago by wuxb
comment:1 Changed 3 years ago by simonmar
- Milestone set to 7.4.1
- Owner set to simonmar
- Priority changed from normal to high
comment:3 Changed 3 years ago by simonmar
- Resolution set to wontfix
- Status changed from new to closed