[zeromq-dev] zmq::poll timeout returns immediately on MacOS/X 10.5

Steven McCoy steven.mccoy at miru.hk
Fri Jun 11 10:17:07 CEST 2010


On 11 June 2010 16:11, Steven McCoy <steven.mccoy at miru.hk> wrote:

> "It takes 324 cycles per call to complete 1 million GTOD calls without
> RDTSCP and 221 cycles per call with the capability."
>
>
>
Compare this with HPET which I clock about 500ns when using mmap(), it would
be significantly slower when using libc IO to read from the device.

WIthout RDTSCP or HPET you can use CPUID+RDTSC or complicated tracking of
current cores and TSC offsets, etc, which is absolutely broken on
hyperthreading processors.

-- 
Steve-o
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