[Asterisk-Users] FYI on zttool output on SMP system

[Steven]

--- Results after 56 passes ---
Best: 100.000000 -- Worst: 99.987793 -- Average: 99.999564
Only 2 were 99.987793, the 54 others were all 100.000000.

I got this by making the changes below on my dual proc Dell 1750.

setpci -v -s 01:08.1 LATENCY_TIMER=8
setpci -v -s 00:0f.1 LATENCY_TIMER=8
setpci -v -s 01:04.0 LATENCY_TIMER=8
setpci -v -s 01:02.0 LATENCY_TIMER=8
setpci -v -s 00:0f.2 LATENCY_TIMER=8
setpci -v -s 01:04.0 LATENCY_TIMER=8 (these are USB, SCSI HW RAID driver, Ethernet, Video, etc. I did not alter ZAP cards, nor any 
bridges or buses)

echo 1 > /proc/irq/17/smp_affinity (Ethernet)
echo 1 > /proc/irq/18/smp_affinity (SCSI HW RAID Driver)
echo 2 > /proc/irq/20/smp_affinity (TDM)
echo 2 > /proc/irq/24/smp_affinity (TE411P)

I also turned of the startup of irqbalance.

The setpci changes did the most work concerning reaching 100% in zttest.

Irqbalance was causing the the processor handling the interrupts of the zap cards to change very often.
This would impose a delay during the change and cause the zttest numbers to drop/be inconsistent.

Because I turned irqbalance off, the irqs are processed round robin style, which is also not good.
Therefore, I hard coded the processor affinity for the zap cards to one proc and all other high load irqs to the other proc.
If you have more than 2 procs, you can spread them out even more. If you do not turn off irqbalance, the affinity changes will be 
overwritten by it.

I made these changes on a live system without issue.
I set these changes in  /etc/rc.d/rc.local to reset them after reboots.

-- 
-- 
Steven

May you have the peace and freedom that come from abandoning all hope of having a better past.
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