Daniel Walker wrote:
Seems like the check should really be using something like time_before()
time_after() which takes the rollover into account .. What I don't
understand is why we don't see those on x86 ..
Probably due to the fact it is a 64-bit counter. Even with
a free running rate of 10Ghz it would take nearly 60 years
to wrap.
On PPC and ARM 32-bit counters seems to be common which limits
range unless a prescaler is available. The better solution is
to detect wrap as a prescaled 32 bit measurement will eventually
run out of usable resolution as core frequency increases. That is
assuming 64-bit counters don't eventually show up in these
architectures.
-john
--
john.cooper@third-harmonic.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]