On Sun, 6 Jul 2008, Justin Piszcz wrote:
On Sat, 5 Jul 2008, Justin Piszcz wrote:
On Sat, 5 Jul 2008, Robert Hancock wrote:
In short, utilizing Raptors (especially veliciraptors)+NCQ on the ICH8 w/AHCI
& other cards in a RAID 5 configuration is a death trap (a good way to lose
your data), it appears unsafe to use NCQ w/raptors in a RAID 5
configuration. I've defaulted back to disabling it like I always do
and my RAID5 is rebuilding now.
After the rebuild is completed I will perform more testing.
Running many parallel, tar, untar and copies of big fileskernel tarball and the kernel
source tree)
$ ps auxww | grep -c cp
437
$ ps auxww | grep -c tar
71
More than ~50k context switches..
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
9 8 160 48092 160 6640044 0 0 524 21776 2264 50571 0 27 30 43
0 9 160 46572 160 6642572 0 0 220 22956 2032 45197 0 40 11 49
0 47 160 51424 160 6642800 0 0 0 22900 1799 39694 0 57 5 38
0 6 160 48916 160 6646272 0 0 112 23932 1763 41746 0 49 13 38
0 7 160 49316 160 6646192 0 0 0 25712 1513 37190 0 20 30 50
0 7 160 49240 160 6646264 0 0 0 28352 1853 38319 0 27 18 55
0 1 160 46652 160 6649688 0 0 548 22800 1933 34609 0 22 69 8
0 0 160 47032 160 6651108 0 0 2268 23652 1998 40729 0 22 56 22
1 0 160 47192 160 6651580 0 0 340 21220 1718 34293 1 17 60 23
This is with the "noapic" boot option and NCQ disabled.
If there are no further errors I will reboot once more and re-run these tests
without the "noapic" boot option and NCQ+irqbalance disabled as before I left
NCQ enabled when irqbalance was disabled.
Trying to find a pattern here but not having much luck.
When all is said and done with over > 500 processes doing I/O with NCQ
disabled and IRQ balance disabled w/noapic, I could not reproduce the
problem.
The problem here is look at the IRQ routing, nearly every device is on IRQ 11:
$ cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
0: 100 0 0 0 XT-PIC-XT timer
1: 2 0 0 0 XT-PIC-XT i8042
2: 0 0 0 0 XT-PIC-XT cascade
8: 1 0 0 0 XT-PIC-XT rtc
9: 60454 0 0 0 XT-PIC-XT acpi, HDA Intel, eth2
10: 129911 0 0 0 XT-PIC-XT pata_marvell, uhci_hcd:usb4, eth1
11: 10278157 0 0 0 XT-PIC-XT sata_sil24, sata_sil24, sata_sil24, ohci1394, ehci_hcd:usb1, ehci_hcd:usb2, uhci_hcd:usb3, uhci_hcd:usb5, uhci_hcd:usb6, uhci_hcd:usb7, i915@pci:0000:00:02.0
12: 4 0 0 0 XT-PIC-XT i8042
377: 3027113 0 0 0 PCI-MSI-edge eth0
378: 9168537 0 0 0 PCI-MSI-edge ahci
NMI: 0 0 0 0 Non-maskable interrupts
LOC: 9832917 9837364 9833540 9842241 Local timer interrupts
RES: 2313942 5729262 5207216 5776735 Rescheduling interrupts
CAL: 24888 884 25272 25155 function call interrupts
TLB: 7990 21120 23055 43247 TLB shootdowns
TRM: 0 0 0 0 Thermal event interrupts
THR: 0 0 0 0 Threshold APIC interrupts
SPU: 0 0 0 0 Spurious interrupts
ERR: 0
Justin.
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