Messages in this thread | ![/](/images/icornerl.gif) | | From | John Bradford <> | Subject | Re: detecting hyperthreading in linux 2.4.19 | Date | Thu, 9 Jan 2003 21:54:05 +0000 (GMT) |
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> > Is there a way for a userspace program running on linux 2.4.19 to tell > > the difference between a single hyperthreaded xeon P4 with HT enabled > > and a dual hyperthreaded xeon P4 with HT disabled? The /proc/cpuinfos > > for the two cases are indistinguishable. > > I don't know of any way to do this in userland. The whole point is that the > sibling processors are supposed to look like real ones. > > You _could_ try running two processes simultaneously in tight spin loops for > 100 million cycles and comparing the amount of real time consumed. That > would be rather unreliable and kludgey though.
If /proc/interrupts shows a processor is handling interrupts then it is definitely a 'real' one. If it isn't handling interrupts, it may or may not be a 'real' one. That's another unreliable and kludgey way to tell the difference :-).
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