Messages in this thread | | | Date | Wed, 30 Jun 2010 11:38:17 +0530 | Subject | Interrupt Affinity in SMP | From | Hari LKML <> |
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Hi All,
We have HP DL380 Server with 48GB of DDR3/1333 MHz RAM, 4 1Gbps NIC Ports, 1 External RAID Card, 1 Internal RAID Card and 2 Intel(R) Xeon(R) CPU X5570 @ 2.93GHz used as an NFS storage server. Running Ubuntu 9.10 2.6.31-14-server. (The Storage is used as an NFS storage for more than 300VMs running using Citrix XenServer)
For More info on the Hard ware configuration http://h18000.www1.hp.com/products/quickspecs/12028_div/12028_div.html
With HTT enabled in BIOS i can see 16 CPU(0-15) as per cat /proc/cpuinfo.
The problem is all the interrupts are handled by CPU0, as per /proc/interrupts including the timer interrupts. And the value of /proc/irq default_smp_affinity is ffff. Also for all the interrupts the smp_affinity is ffff.
What i believe is with these setting all the interrupts should be handled by the First 8 CPUs in a Round robin Fashion. Or in our case at worse by the first 4 cores (since HTT is enabled - *not clear with this concept though some once please put some light over here also for better understanding :-)* ).
Also i tried to edit the smp_affinity of an interrupt to a value 0004 to test that if the interrupt is handled by some other core. But i was unable to edit this value in a running system i got the access denied error so i can't do this.
Please help me in distributing the interrupts among the other cores of my system which might increase some performance of my system.
let me know if you need some log of the system or some other info about the system.
Hari -- 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/
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