Comments on: my package of the day: irqbalance http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/ Wed, 16 Jun 2010 13:20:55 +0000 hourly 1 http://wordpress.org/?v=3.0 By: psilo http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-1119 psilo Wed, 11 Jun 2008 05:21:02 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-1119 mpstat is a nice tool to get a quick overview of per-core situation: psilo@fbx:~$ mpstat -P ALL Linux 2.6.22-14-generic (fbx.physnet) 06/10/2008 11:18:39 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s 11:18:39 PM all 10.41 0.02 2.43 0.26 0.03 0.15 0.00 86.71 97.62 11:18:39 PM 0 10.73 0.02 2.36 0.42 0.06 0.28 0.00 86.13 90.22 11:18:39 PM 1 10.09 0.01 2.49 0.09 0.00 0.02 0.00 87.28 7.40 mpstat is a nice tool to get a quick overview of per-core situation:

psilo@fbx:~$ mpstat -P ALL
Linux 2.6.22-14-generic (fbx.physnet) 06/10/2008

11:18:39 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
11:18:39 PM all 10.41 0.02 2.43 0.26 0.03 0.15 0.00 86.71 97.62
11:18:39 PM 0 10.73 0.02 2.36 0.42 0.06 0.28 0.00 86.13 90.22
11:18:39 PM 1 10.09 0.01 2.49 0.09 0.00 0.02 0.00 87.28 7.40

]]> By: vanilla-kernel http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-1012 vanilla-kernel Wed, 04 Jun 2008 14:03:22 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-1012 Not really, I guess something new in the kernel. Maybe 30,3% ( 56,0) : Rescheduling interrupts what ever that does ;-) Not really, I guess something new in the kernel. Maybe

30,3% ( 56,0) : Rescheduling interrupts

what ever that does ;-)

]]> By: ccm http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-1005 ccm Tue, 03 Jun 2008 18:58:23 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-1005 @vanila-kernel: And do you have the very hint, which module/setting is responsible for this behaviour? @vanila-kernel:

And do you have the very hint, which module/setting is responsible for this behaviour?

]]> By: vanila-kernel http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-1004 vanila-kernel Tue, 03 Jun 2008 15:38:00 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-1004 powertop tells you: Suggestion: Disable the CONFIG_IRQBALANCE kernel configuration option. The in-kernel irq balancer is obsolete and wakes the CPU up far more than needed. In a recent kernel (2.6.26-rc4) even with "CONFIG_IRQBALANCE is not set" and without the daemon: :-) CPU0 CPU1 0: 10799723 11144542 IO-APIC-edge timer 1: 3242 3004 IO-APIC-edge i8042 9: 842 681 IO-APIC-fasteoi acpi 12: 1200398 1168041 IO-APIC-edge i8042 14: 176001 169192 IO-APIC-edge ata_piix 15: 0 0 IO-APIC-edge ata_piix 16: 8376 8404 IO-APIC-fasteoi uhci_hcd:usb1, i915@pci:0000:00:02.0 18: 12 8 IO-APIC-fasteoi ehci_hcd:usb3, uhci_hcd:usb6 19: 0 0 IO-APIC-fasteoi uhci_hcd:usb5 21: 0 0 IO-APIC-fasteoi uhci_hcd:usb2 22: 1323453 1025204 IO-APIC-fasteoi HDA Intel 23: 4584 4436 IO-APIC-fasteoi uhci_hcd:usb4, ehci_hcd:usb7 220: 1699398 1692895 PCI-MSI-edge eth0 221: 107476 107021 PCI-MSI-edge ahci NMI: 0 0 Non-maskable interrupts LOC: 6378217 6929446 Local timer interrupts RES: 6352006 7088681 Rescheduling interrupts CAL: 17466 2619 function call interrupts TLB: 3540 3489 TLB shootdowns TRM: 0 0 Thermal event interrupts SPU: 0 0 Spurious interrupts ERR: 0 MIS: 0 powertop tells you: Suggestion: Disable the CONFIG_IRQBALANCE kernel configuration option.
The in-kernel irq balancer is obsolete and wakes the CPU up far more than needed.

In a recent kernel (2.6.26-rc4) even with “CONFIG_IRQBALANCE is not set” and without the daemon: :-)

CPU0 CPU1
0: 10799723 11144542 IO-APIC-edge timer
1: 3242 3004 IO-APIC-edge i8042
9: 842 681 IO-APIC-fasteoi acpi
12: 1200398 1168041 IO-APIC-edge i8042
14: 176001 169192 IO-APIC-edge ata_piix
15: 0 0 IO-APIC-edge ata_piix
16: 8376 8404 IO-APIC-fasteoi uhci_hcd:usb1, i915@pci:0000:00:02.0
18: 12 8 IO-APIC-fasteoi ehci_hcd:usb3, uhci_hcd:usb6
19: 0 0 IO-APIC-fasteoi uhci_hcd:usb5
21: 0 0 IO-APIC-fasteoi uhci_hcd:usb2
22: 1323453 1025204 IO-APIC-fasteoi HDA Intel
23: 4584 4436 IO-APIC-fasteoi uhci_hcd:usb4, ehci_hcd:usb7
220: 1699398 1692895 PCI-MSI-edge eth0
221: 107476 107021 PCI-MSI-edge ahci
NMI: 0 0 Non-maskable interrupts
LOC: 6378217 6929446 Local timer interrupts
RES: 6352006 7088681 Rescheduling interrupts
CAL: 17466 2619 function call interrupts
TLB: 3540 3489 TLB shootdowns
TRM: 0 0 Thermal event interrupts
SPU: 0 0 Spurious interrupts
ERR: 0
MIS: 0

]]> By: jldugger http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-997 jldugger Mon, 02 Jun 2008 20:00:11 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-997 irqbalance is not for everyone. Laptops, for example. If you can do per core throttling and idling, it might save more power to only wake one CPU up and leave the other idle for minor processing. Of course this hurts throughput and latency. irqbalance is not for everyone. Laptops, for example. If you can do per core throttling and idling, it might save more power to only wake one CPU up and leave the other idle for minor processing. Of course this hurts throughput and latency.

]]> By: Vadim P. http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-993 Vadim P. Mon, 02 Jun 2008 15:59:08 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-993 I always stumble upon things like this. Try and do something, only to realize Ubuntu already does it... *sigh* it's popular for a reason I guess. I always stumble upon things like this. Try and do something, only to realize Ubuntu already does it… *sigh* it’s popular for a reason I guess.

]]> By: ccm http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-987 ccm Mon, 02 Jun 2008 14:37:26 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-987 @lissyx: Thanks for your comment. Seems you are right, though the question is, why the balance works in hardy without irqbalance installed. @lissyx: Thanks for your comment. Seems you are right, though the question is, why the balance works in hardy without irqbalance installed.

]]> By: lissyx http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-986 lissyx Mon, 02 Jun 2008 14:30:41 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-986 I'm sorry for you guys, but you should have checked in your Ubuntu's kernel's config file : /boot/config-2.6.20-16-generic:CONFIG_IRQBALANCE=y /boot/config-2.6.22-14-generic:# CONFIG_IRQBALANCE is not set /boot/config-2.6.24-16-generic:# CONFIG_IRQBALANCE is not set /boot/config-2.6.24-17-generic:# CONFIG_IRQBALANCE is not set Meaning, Hardy have disabled it ! I’m sorry for you guys, but you should have checked in your Ubuntu’s kernel’s config file :

/boot/config-2.6.20-16-generic:CONFIG_IRQBALANCE=y
/boot/config-2.6.22-14-generic:# CONFIG_IRQBALANCE is not set
/boot/config-2.6.24-16-generic:# CONFIG_IRQBALANCE is not set
/boot/config-2.6.24-17-generic:# CONFIG_IRQBALANCE is not set

Meaning, Hardy have disabled it !

]]> By: erUSUL http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-983 erUSUL Mon, 02 Jun 2008 13:40:27 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-983 I have read many times in lkml that the userspace irbalancer which you describe) is preferred over the in kernel irqbalance. In fact the in kernel one may dissapear soon I have read many times in lkml that the userspace irbalancer which you describe) is preferred over the in kernel irqbalance. In fact the in kernel one may dissapear soon

]]> By: Dan Zappone http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/comment-page-1/#comment-982 Dan Zappone Mon, 02 Jun 2008 13:38:30 +0000 http://www.screenage.de/blog/2008/06/02/my-package-of-the-day-irqbalance/#comment-982 Will this benefit hyper-threaded procs as well? Will this benefit hyper-threaded procs as well?

]]>