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Gigabit/SMP performance problem

DISCUSSION Bill Davidsen 3 participants 3 messages Jan 6, 2003 1 message not in the archive

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#1 lore raw
Quoted 2 lines · Daniel Blueman

It's interesting you have IRQs balanced over the two logical processors. I can't get this on HT Xeons with stock RedHat 7.3 kernel.

I think he's using two physical processors, if by "logical processors" you are thinking HT... I also recall he has HT off, but the original post isn't handy.

Quoted 10 lines

Can you post the exact kernel version string, please?

TIA,
Dan

"Avery Fay" <[email protected]> wrote in message news:<OF256CD297.9F92C038-ON85256CA3.006A4034-85256CA3.00705DEA@symantec.com>...

Quoted 3 lines

Dual Pentium 4 Xeon at 2.4 Ghz. I believe I am using irq load balancing as shown below (seems to be applied to Red Hat's kernel). Here's /proc/interrupts:

Signature · 3 lines
bill davidsen <[email protected]>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.
#2 lore raw

Even with HT turned off on this dual-Xeon box, all IRQs are routed to CPU 0.

Kernel here is the latest RedHat 2.4.18 one.

Just curious what kernel Avery is running...

Dan

Quoted 17 lines · Daniel Blueman
Quoted 3 lines

It's interesting you have IRQs balanced over the two logical processors. I can't get this on HT Xeons with stock RedHat 7.3 kernel.

I think he's using two physical processors, if by "logical processors" you are thinking HT... I also recall he has HT off, but the original post isn't handy.

Quoted 7 lines

Can you post the exact kernel version string, please?

TIA,
Dan

"Avery Fay" <[email protected]> wrote in message

news:<OF256CD297.9F92C038-ON85256CA3.006A4034-85256CA3.00705DEA@symantec.com>...

Quoted 10 lines
Quoted 1 line
Quoted 1 line

Dual Pentium 4 Xeon at 2.4 Ghz. I believe I am using irq load

balancing as

Quoted 2 lines
Quoted 2 lines

shown below (seems to be applied to Red Hat's kernel). Here's /proc/interrupts:

Signature · 3 lines
bill davidsen <[email protected]>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.
Signature · 4 lines
Daniel J Blueman

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#3 lore raw

I've been able to distribute IRQ servicing to other processors on P4 Xeon HT systems as described in the IRQ-affinity.txt file in the kernel-source Documentation directory. Well, it shows up as doing so in /proc/interrupts anyway! Looks like CPUs 0, 2, 4, etc.. are the real processors and 1,3,5, etc.. are the logical processors (which do not handle interrupts).

Quoted 54 lines · Daniel Blueman

Even with HT turned off on this dual-Xeon box, all IRQs are routed to CPU 0.

Kernel here is the latest RedHat 2.4.18 one.

Just curious what kernel Avery is running...

Dan

Quoted 22 lines · Daniel Blueman
Quoted 7 lines

It's interesting you have IRQs balanced over the two logical processors. I can't get this on HT Xeons with stock RedHat 7.3 kernel.

I think he's using two physical processors, if by "logical processors" you are thinking HT... I also recall he has HT off, but the original post isn't handy.

Quoted 8 lines

Can you post the exact kernel version string, please?

TIA,
Dan

"Avery Fay" <[email protected]> wrote in message

news:<OF256CD297.9F92C038-ON85256CA3.006A4034-85256CA3.00705DEA@symantec.com>...

Quoted 16 lines
Quoted 3 lines
Quoted 3 lines

Dual Pentium 4 Xeon at 2.4 Ghz. I believe I am using irq load

balancing as

Quoted 3 lines
Quoted 3 lines

shown below (seems to be applied to Red Hat's kernel). Here's /proc/interrupts:

Signature · 3 lines
bill davidsen <[email protected]>
 CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.
Signature · 5 lines
-[========================]-
-[      Brian Tinsley     ]-
-[ Chief Systems Engineer ]-
-[        Emageon         ]-
-[========================]-