Determining if the current processor is Hyperthreaded

Determining if the current processor is Hyperthreaded

[Athul Acharya]

Hey folks,

Is there a quick way to determine if the current processor is
Hyperthreaded, and if so, which logical processor represents the other
thread on the chip? Please cc replies to me as I am not subscribed to
the list :-)

Thanks,

Athul

Re: Determining if the current processor is Hyperthreaded

[Bill Davidsen]

Athul Acharya wrote:
> Hey folks,
> 
> Is there a quick way to determine if the current processor is
> Hyperthreaded, and if so, which logical processor represents the other
> thread on the chip? Please cc replies to me as I am not subscribed to
> the list :-)

Look at /proc/cpuinfo and see if "siblings" is listed and more than one. 
There is no "other thread" there, it's like "which one is the other hand?"
-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me

Re: Determining if the current processor is Hyperthreaded

[Athul Acharya]

On 8/2/05, Bill Davidsen <davidsen@tmr.com> wrote:
> Athul Acharya wrote:
> > Hey folks,
> >
> > Is there a quick way to determine if the current processor is
> > Hyperthreaded, and if so, which logical processor represents the other
> > thread on the chip? Please cc replies to me as I am not subscribed to
> > the list :-)
> 
> Look at /proc/cpuinfo and see if "siblings" is listed and more than one.
> There is no "other thread" there, it's like "which one is the other hand?"


Sorry, I should've been more specific -- I mean within the kernel. 
That is, I want to know whether the current cpu I (kernel code) am
executing on is hyperthreaded, and if so, which logical cpu represents
the other thread on chip.

Athul

Re: Determining if the current processor is Hyperthreaded

[Athul Acharya]

On 8/2/05, Athul Acharya <aacharya@gmail.com> wrote:
> That is, I want to know whether the current cpu I (kernel code) am
> executing on is hyperthreaded, and if so, which logical cpu represents
> the other thread on chip.

Trying again, as it seems like a simple thing that really should exist
 --  is_cpu_hyperthreaded(smp_processor_id()) -- or something similar.
 Anyone?

Athul

Re: Determining if the current processor is Hyperthreaded

[Athul Acharya]

On 8/5/05, Athul Acharya <aacharya@gmail.com> wrote:
> On 8/2/05, Athul Acharya <aacharya@gmail.com> wrote:
> > That is, I want to know whether the current cpu I (kernel code) am
> > executing on is hyperthreaded, and if so, which logical cpu represents
> > the other thread on chip.
> 
> Trying again, as it seems like a simple thing that really should exist
>  --  is_cpu_hyperthreaded(smp_processor_id()) -- or something similar.
>  Anyone?

Is anyone receiving this?  I should've mentioned in subsequent mails
(I did in the original) that I'm not subscribed so any replies need to
be cc'd to me :)

Athul