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  • 1.  Am I am having IRQ Conflict

    Posted Jan 25, 2012 12:16 AM

    Hi Forum, After doing a clean install I am noticing very slow disk IO performanc. I am getting about 11 MBP/s. My Specifications are below

    Motherboard: Asus DSBF-D12/SAD

    Raid Card: Perc 5i with 4 disks in Raid 5

    After doing some inverstigation I found that it could be related to IRQ conflict so I did some search to find the IRQ related information from ESXi 5. Following is the output of command that I ran and I need your expert opinon to check if this could be related to IRQ sharing.

    vmkvsitools hwinfo -i

    ~ # vmkvsitools hwinfo -i
    Vector    PCPU  0    PCPU  1    PCPU  2    PCPU  3
    0x20:           0          0          0          0 VMK ACPI Interrupt
    0x30:         685          0          0          0 VMK keyboard
    0x58:           1          0          0          0 VMK mouse
    0x68:        1061       3274        387        313 VMK ata_piix
    0x70:           1          0          0          0 VMK ata_piix
    0x78:        2296        101          0          0 VMK megasas
    0xa0:          16         13        594        943 VMK vmnic0
    0xa8:         237        242        272        632 VMK vmnic1
    0xdf:      271917     128257     123804     114660 VMK timer
    0xe1:           0          0          0          0 VMK monitor
    0xe9:        1895       2466       1300       1573 VMK resched
    0xf1:        5340       2433       4713       4636 VMK tlb
    0xf9:           0          0          0          0 VMK noop
    0xfc:           0          0          0          0 VMK thermal
    0xfd:           0          0          0          0 VMK lint1
    0xfe:           0          0          0          0 VMK error
    0xff:           0          0          0          0 VMK spurious

    vmkvsitools hwinfo -p

    ~ # vmkvsitools hwinfo -p
    Seg:Bus:Sl.F Vend:Dvid Subv:Subd ISA/irq/Vec P M Module       Name
                                    Spawned bus
    000:000:00.0 8086:25d8 1043:81db  0/   /     A V              PCIe RP[000:000:00.0]
    000:000:02.0 8086:25f7 0000:0000               V              PCIe RP[000:000:02.0]
                                     001
    000:000:03.0 8086:25e3 0000:0000               V              PCIe RP[000:000:03.0]
                                     006
    000:000:04.0 8086:25f8 0000:0000               V              PCIe RP[000:000:04.0]
                                     007
    000:000:05.0 8086:25e5 0000:0000               V              PCIe RP[000:000:05.0]
                                     010
    000:000:06.0 8086:25f9 0000:0000               V              PCIe RP[000:000:06.0]
                                     011
    000:000:07.0 8086:25e7 0000:0000               V              PCIe RP[000:000:07.0]
                                     012
    000:000:16.0 8086:25f0 1043:81db               V
    000:000:16.1 8086:25f0 1043:81db               V
    000:000:16.2 8086:25f0 1043:81db               V
    000:000:17.0 8086:25f1 1043:81db               V
    000:000:19.0 8086:25f3 1043:81db               V
    000:000:21.0 8086:25f5 1043:81db               V
    000:000:22.0 8086:25f6 1043:81db               V
    000:000:28.0 8086:2690 0000:0000 11/ 11/0x98 A V              PCIe RP[000:000:28.0]
                                     013
    000:000:30.0 8086:244e 0000:0000               V
                                     014
    000:000:31.0 8086:2670 1043:81dc               V
    000:000:31.1 8086:269e 1043:81dc 255/   /0x78 A V ata_piix     vmhba0
    000:000:31.3 8086:269b 1043:81dc 10/   /     B V
    000:001:00.0 8086:3500 0000:0000               V
                                     002
    000:001:00.3 8086:350c 0000:0000               V
                                     005
    000:002:00.0 8086:3510 0000:0000               V
                                     003
    000:002:02.0 8086:3518 0000:0000               V
                                     004
    000:004:00.0 8086:1096 1043:8217  5/  5/0xa0 A V e1000e       vmnic0
    000:004:00.1 8086:1096 1043:8217 10/ 10/0xa8 B V e1000e       vmnic1
    000:007:00.0 8086:0370 0000:0000               V
                                     008
    000:007:00.2 8086:0372 0000:0000               V
                                     009
    000:008:14.0 1028:0015 1028:1f02  5/  5/0x78 A V megaraid_sas vmhba1
    000:014:02.0 1002:515e 1043:81de 11/ 11/0x98 A V

    As you can notice in the output above same IRQ (5) is being shared by both vmhba1 (PERC 5i) and vmnic0. Could this be the culprit for poor disk performance?

    Regards,



  • 2.  RE: Am I am having IRQ Conflict

    Posted Jan 25, 2012 12:56 AM

    does your raid card has battery-backed cache? i would see significant performance bump when it's added.



  • 3.  RE: Am I am having IRQ Conflict

    Posted Jan 25, 2012 01:08 AM

    Yes it does and the health status shows its fully charged and active.



  • 4.  RE: Am I am having IRQ Conflict

    Posted Jan 25, 2012 01:15 AM

    Can you confirm that you configured the RAID/logical volume for write-back operation?

    André



  • 5.  RE: Am I am having IRQ Conflict

    Posted Jan 25, 2012 01:17 AM

    Hi André, Yes it been configured for Write Back. Could it be the IRQ issue?



  • 6.  RE: Am I am having IRQ Conflict

    Posted Jan 25, 2012 02:39 AM

    Extremely unlikely.

    All modern NICs dont use much in the way of IRQs, and even then, IRQ sharing is so efficient its very rare to create a problem.

    You likely have some other issue.