[ut2004] Maybe OT, what timer func does UT use?
J. Ryan Earl
heretic at clanhk.org
Wed Mar 31 16:59:43 EST 2004
Ryan C. Gordon wrote:
>>I'm curious, what timer function do you use to calculate the time spent
>>on each frame? What's the most accurate under Linux?
>We're using gettimeofday().
And that's high enough precision?
>We used to read the time stamp counter directly (with the rdtsc opcode),
>but variable frequency CPUs (AMD's Cool'n'Quiet, Intel's SpeedStep) break
>this, as do unsync'd CPUs in an SMP box.
I saw this mechanism, but it seemed usable only on x86 boxen.
>We still use the PowerPC performance counters on MacOS, though this will
>probably change to gettimeofday(), too, since it "future-proofs" the
>Windows uses timeGetTime().
Why not QueryPerformanceCounter/Frenquency?
>All of these methods are very fast.
I was more worried about precision. It seems 1 ms accuracy is all we
get. There isn't any sort of reliable, cross-platform sub-millisecond
More information about the ut2004