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SubjectRe: Error in x86 CPU capabilities starting with test5/6
Christoph Rohland wrote:
>
> Hi Alan,
>
> On Fri, 17 Nov 2000, Alan Cox wrote:
> > Even checking the cpuinfo for the TSC should be done with care, and
> > its far far better to use gettimeofday unless doing very tiny
> > timings (eg for optimising code paths)
>
> gettimeofday is _way_ to slow for a lot of every day uses. So
> applications will use rdtsc until we have some really fast
> (non-syscall) way to have high resolution time diffs.

IIRC, this came up a long time ago WRT Apache, which made a lot of
gettimeofday() calls. Someone (Linus?) proposed the solution of a
'magic page' which holds information like gettimeofday() stuff, but
could be handled much more rapidly than a standard syscall.

--
Jeff Garzik |
Building 1024 | The chief enemy of creativity is "good" sense
MandrakeSoft | -- Picasso
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