Multi Core and Taskset

[HBS|Ryan]

SysInfo

Fedora Core 7
2.6.24-rc5 #2 SMP PREEMPT set for 1000fps
(I use a release candidate so i can set the clocksource to HPET)
2 * AMD Opteron 2218 2.6ghz (4 Cores total)
2 gigs of ram

Problem:

When I set srcds to run on a specific core using tasket, the defentivly lags down some. CPU stays the same (roughly), but the FPS starts to get irregular dropping all the way to the teens.

if i don't set a specific core it doesn't happen. i get a solid 993fps

any ideas?
thanks

[Masher]

I'd assume something else is using the core. Not setting an affinity allows the process to run on any core leaving the os to select which core to run it on. So when one core is busy the os will move the thread to another idle core.

[HBS|Ryan]

hmmmm. ok. I have tried every core at different times, but they would still stuggle. so that could be it.
last time i tried to disable smp in a kernel build, it only showed 1 core afterward. Is there any way to disable all task schedualing, but still be able to see all 4 cores?

[Enemy1]

But - if you got clients in all game-servers then you will get more stable fps if its not switching between cores ..

[HBS|Ryan]

anyone else have any thoughts on this? it still kinda bugs me

[fqdn]

are you starting the server then using taskset on the resulting pid or do you use taskset and then call the startup line? i got funny cpu usage doing it the first way and working normally using the second.

so i have a server.sh which contains srcds_run blah blah, and then a startserver.sh which is "taskset blah ./server.sh"

[HBS|Ryan]

yea ive tried both methods and get the same result