lkml.org 
[lkml]   [2003]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: detecting hyperthreading in linux 2.4.19
Jason Lunz wrote:
>
> jamesclv@us.ibm.com said:
> > 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.
>
> That's unfortunately not always true. I'm writing a program that will
> run on a system that will be doing high-load routing. Testing has shown
> that we get better performance when binding each NIC's interrupts to a
> separate physical processor using /proc/irq/*/smp_affinity (especially
> when all the interrupts would hit the first CPU, another problem i've
> yet to address). That only works for real processors, though, not
> HT siblings.

Strange, I'm doing the very same thing (not with NICs though) using the
local_irq_desc
at the driver level or via /proc/irq/*/smp_affinity method and both work fine.
2.4.18 and 2.4.20 both work here but haven't actually used 2.4.19.

>
> I'm writing a program to run on machines of unknown (by me)
> configuration, that will spread out the NIC interrupts appropriately.
> So userspace needs to know the difference, at least until interrupts can
> be automatically distributed by the kernel in a satisfactory way.

My userland app doesn't know the difference and works fine whether HT or not.
At least according to /proc/interrupts, xosview, and the actual performance of
my app.

Mark
-
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/

\
 
 \ /
  Last update: 2005-03-22 13:32    [W:0.055 / U:4.212 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site