[uae] Re: Some Progress With the Cocoa GUI
- From: Richard Drummond <evilrich@xxxxxxxxxxxxxx>
- To: uae@xxxxxxxxxxxxx
- Date: Sun, 17 Apr 2005 00:13:16 -0500
Hi Axel
On Saturday 16 April 2005 08:56 am, Axel Dörfler wrote:
> I would guess it's pretty low overhead on most platforms, at least it
> would be worth a try.
On the platforms I've tested so far, it does appear that the resolution of
gettimeofday() should be sufficient and the overhead is minimal.
I've attached some preliminary results of the platforms I've tested so far in
case anybody's interested. Don't read too much into these numbers.
> I'm pretty sure it's not tied to the CPU frequency, so it should be a
> good candidate.
Yes. I remember reading somewhere that it's derived from the front-side bus
speed. Must try and find some official documentation on this.
> It's measured by BeOS on startup; BeOS depends its timing on the TSC
> itself (that's why it has numerous problems on CPUs that change their
> frequency). So it's as exact as BeOS' timing.
Ah. Interesting.
> There is probably just not that much choice in userland.
Not on Linux. Other ('proper') Unices seem to have a lot more functionality in
this regard. E.g. get_hrtime() on Solaris.
Cheers,
Rich
PowerMac 9500 333 MHz PPC750 - Mac OS 10.2
------------------------------------------
Testing gettimeofday()
----------------------
Testing granularity...
Estimated granularity : 14 usecs
Testing overhead
Doing 10000000 iterations...
start time: 1113712622 secs 111152 usecs
end time: 1113712668 secs 672116 usecs
total time: 46 secs 560964 usecs
time per call: 4.656096 usecs
PowerMac 9500 333 MHz PPC750 - Linux 2.6.8.1
--------------------------------------------
Testing gettimeofday()
----------------------
Testing granularity...
Estimated granularity : 3 usecs
Testing overhead
Doing 10000000 iterations...
start time: 1113731911 secs 147279 usecs
end time: 1113731918 secs 699845 usecs
total time: 7 secs 552566 usecs
time per call: 0.755257 usecs
Starmax 3000 233 MHz PPC750 - Linux 2.4.21
------------------------------------------
Testing gettimeofday()
----------------------
Testing granularity...
Estimated granularity : 3 usecs
Testing overhead
Doing 10000000 iterations...
start time: 1113712725 secs 358999 usecs
end time: 1113712737 secs 785402 usecs
total time: 12 secs 426403 usecs
time per call: 1.242640 usecs
1800 MHz Athlon XP 2200+ - Linux 2.6.10
---------------------------------------
Testing gettimeofday()
----------------------
Testing granularity...
Estimated granularity : 2 usecs
Testing overhead
Doing 10000000 iterations...
start time: 1113713402 secs 376501 usecs
end time: 1113713420 secs 607344 usecs
total time: 18 secs 230843 usecs
time per call: 1.823084 usecs
AmigaOne 800MHz PPC7455 - AmigaOS 4.0 beta
------------------------------------------
Testing gettimeofday()
----------------------
Testing granularity...
Estimated granularity : 3 usecs
Testing overhead
Doing 10000000 iterations...
start time: 1113634421 secs 230755 usecs
end time: 1113634427 secs 674649 usecs
total time: 6 secs 443894 usecs
time per call: 0.644389 usecs
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