Messages in this thread | | | Date | Fri, 10 Jan 2003 07:29:22 -0500 | From | Mark Hounschell <> | Subject | Re: detecting hyperthreading in linux 2.4.19 |
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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.
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