* arm64 sched_clock cpu accounting @ 2015-11-18 19:46 Mario Smarduch 2015-11-19 2:20 ` Mario Smarduch 0 siblings, 1 reply; 7+ messages in thread From: Mario Smarduch @ 2015-11-18 19:46 UTC (permalink / raw) To: linux-arm-kernel Hello, I noticed sched clock accounting can be enabled when arch-timer is initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on need all accounting options are fine, but irq time accounting appears to be most preferable. Any thoughts? Is it fine to enable it? Thanks, Mario ^ permalink raw reply [flat|nested] 7+ messages in thread
* arm64 sched_clock cpu accounting 2015-11-18 19:46 arm64 sched_clock cpu accounting Mario Smarduch @ 2015-11-19 2:20 ` Mario Smarduch 2015-12-02 18:07 ` Christoffer Dall 0 siblings, 1 reply; 7+ messages in thread From: Mario Smarduch @ 2015-11-19 2:20 UTC (permalink / raw) To: linux-arm-kernel Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time is reported. That's with running a ping flood - 1200 int/s, not sure why wouldn't any irq time be reported? The other two modes report irq time as expected. On 11/18/2015 11:46 AM, Mario Smarduch wrote: > Hello, > I noticed sched clock accounting can be enabled when arch-timer is > initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' > selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. > After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on > need all accounting options are fine, but irq time accounting appears to be most > preferable. > > Any thoughts? Is it fine to enable it? > > Thanks, > Mario > > > _______________________________________________ > kvmarm mailing list > kvmarm at lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm > ^ permalink raw reply [flat|nested] 7+ messages in thread
* arm64 sched_clock cpu accounting 2015-11-19 2:20 ` Mario Smarduch @ 2015-12-02 18:07 ` Christoffer Dall 2015-12-02 23:42 ` Mario Smarduch 0 siblings, 1 reply; 7+ messages in thread From: Christoffer Dall @ 2015-12-02 18:07 UTC (permalink / raw) To: linux-arm-kernel Hi Mario, On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote: > Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time > is reported. That's with running a ping flood - 1200 int/s, not sure why > wouldn't any irq time be reported? The other two modes report irq time as expected. > > On 11/18/2015 11:46 AM, Mario Smarduch wrote: > > Hello, > > I noticed sched clock accounting can be enabled when arch-timer is > > initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' > > selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. > > After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on > > need all accounting options are fine, but irq time accounting appears to be most > > preferable. > > > > Any thoughts? Is it fine to enable it? > > Is any of this related to KVM? -Christoffer ^ permalink raw reply [flat|nested] 7+ messages in thread
* arm64 sched_clock cpu accounting 2015-12-02 18:07 ` Christoffer Dall @ 2015-12-02 23:42 ` Mario Smarduch 2015-12-03 9:29 ` Will Deacon 2015-12-03 18:45 ` Mario Smarduch 0 siblings, 2 replies; 7+ messages in thread From: Mario Smarduch @ 2015-12-02 23:42 UTC (permalink / raw) To: linux-arm-kernel On 12/2/2015 10:07 AM, Christoffer Dall wrote: > Hi Mario, > > On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote: >> Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time >> is reported. That's with running a ping flood - 1200 int/s, not sure why >> wouldn't any irq time be reported? The other two modes report irq time as expected. >> >> On 11/18/2015 11:46 AM, Mario Smarduch wrote: >>> Hello, >>> I noticed sched clock accounting can be enabled when arch-timer is >>> initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' >>> selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. >>> After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on >>> need all accounting options are fine, but irq time accounting appears to be most >>> preferable. >>> >>> Any thoughts? Is it fine to enable it? >>> > Is any of this related to KVM? Indirectly, given the guest should yield same results. To be on the safe side I ran the guest in all combinations (7) to confirm that's the case. Also verified that guest time on host appears fine in all these configurations. It takes extra effort to get the guest time as opposed to other modes. - Mario > > -Christoffer > ^ permalink raw reply [flat|nested] 7+ messages in thread
* arm64 sched_clock cpu accounting 2015-12-02 23:42 ` Mario Smarduch @ 2015-12-03 9:29 ` Will Deacon 2015-12-03 18:26 ` Mario Smarduch 2015-12-03 18:45 ` Mario Smarduch 1 sibling, 1 reply; 7+ messages in thread From: Will Deacon @ 2015-12-03 9:29 UTC (permalink / raw) To: linux-arm-kernel On Wed, Dec 02, 2015 at 03:42:10PM -0800, Mario Smarduch wrote: > On 12/2/2015 10:07 AM, Christoffer Dall wrote: > > On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote: > >> Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time > >> is reported. That's with running a ping flood - 1200 int/s, not sure why > >> wouldn't any irq time be reported? The other two modes report irq time as expected. > >> > >> On 11/18/2015 11:46 AM, Mario Smarduch wrote: > >>> Hello, > >>> I noticed sched clock accounting can be enabled when arch-timer is > >>> initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' > >>> selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. > >>> After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on > >>> need all accounting options are fine, but irq time accounting appears to be most > >>> preferable. > >>> > >>> Any thoughts? Is it fine to enable it? > >>> > > Is any of this related to KVM? > > Indirectly, given the guest should yield same results. To be on the safe side I > ran the guest in all combinations (7) to confirm that's the case. > > Also verified that guest time on host appears fine in all these configurations. > It takes extra effort to get the guest time as opposed to other modes. I can take this via the arm64 tree (where it's queued, but I've not pushed anything yet). Will ^ permalink raw reply [flat|nested] 7+ messages in thread
* arm64 sched_clock cpu accounting 2015-12-03 9:29 ` Will Deacon @ 2015-12-03 18:26 ` Mario Smarduch 0 siblings, 0 replies; 7+ messages in thread From: Mario Smarduch @ 2015-12-03 18:26 UTC (permalink / raw) To: linux-arm-kernel On 12/3/2015 1:29 AM, Will Deacon wrote: > On Wed, Dec 02, 2015 at 03:42:10PM -0800, Mario Smarduch wrote: >> On 12/2/2015 10:07 AM, Christoffer Dall wrote: >>> On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote: >>>> Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time >>>> is reported. That's with running a ping flood - 1200 int/s, not sure why >>>> wouldn't any irq time be reported? The other two modes report irq time as expected. >>>> >>>> On 11/18/2015 11:46 AM, Mario Smarduch wrote: >>>>> Hello, >>>>> I noticed sched clock accounting can be enabled when arch-timer is >>>>> initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' >>>>> selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. >>>>> After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on >>>>> need all accounting options are fine, but irq time accounting appears to be most >>>>> preferable. >>>>> >>>>> Any thoughts? Is it fine to enable it? >>>>> >>> Is any of this related to KVM? >> >> Indirectly, given the guest should yield same results. To be on the safe side I >> ran the guest in all combinations (7) to confirm that's the case. >> >> Also verified that guest time on host appears fine in all these configurations. >> It takes extra effort to get the guest time as opposed to other modes. > > I can take this via the arm64 tree (where it's queued, but I've not pushed > anything yet). > > Will Great thanks. > ^ permalink raw reply [flat|nested] 7+ messages in thread
* arm64 sched_clock cpu accounting 2015-12-02 23:42 ` Mario Smarduch 2015-12-03 9:29 ` Will Deacon @ 2015-12-03 18:45 ` Mario Smarduch 1 sibling, 0 replies; 7+ messages in thread From: Mario Smarduch @ 2015-12-03 18:45 UTC (permalink / raw) To: linux-arm-kernel Hi Christoffer, On 12/2/2015 3:42 PM, Mario Smarduch wrote: > > > On 12/2/2015 10:07 AM, Christoffer Dall wrote: >> Hi Mario, >> >> On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote: >>> Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time >>> is reported. That's with running a ping flood - 1200 int/s, not sure why >>> wouldn't any irq time be reported? The other two modes report irq time as expected. >>> >>> On 11/18/2015 11:46 AM, Mario Smarduch wrote: >>>> Hello, >>>> I noticed sched clock accounting can be enabled when arch-timer is >>>> initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING' >>>> selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected. >>>> After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on >>>> need all accounting options are fine, but irq time accounting appears to be most >>>> preferable. >>>> >>>> Any thoughts? Is it fine to enable it? >>>> >> Is any of this related to KVM? > > Indirectly, given the guest should yield same results. To be on the safe side I > ran the guest in all combinations (7) to confirm that's the case. > > Also verified that guest time on host appears fine in all these configurations. > It takes extra effort to get the guest time as opposed to other modes. > > - Mario >> >> -Christoffer >> > _______________________________________________ > kvmarm mailing list > kvmarm at lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm > While on this topic, one use case for RT like apps is run the host in full sched clock accounting mode/NO_HZ_FULL and guest in IRQ time accounting mode/NO_HZ_IDLE. This should make sense for a control plane, gateway guest (using normal IP stack, timers, ..) there you have a lot of transitions between run modes. ANd irq, softirq accounting matters. The host on the other side should be fine running a vCPU in full sched clock mode, you don't expect to many transitions from the vCPU, and less need for irq/softirq accounting if any. I recall you raised the point of run modes when you fixed guest time accounting, but I didn't have a good use case back then for your question. - Mario. ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-12-03 18:45 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2015-11-18 19:46 arm64 sched_clock cpu accounting Mario Smarduch 2015-11-19 2:20 ` Mario Smarduch 2015-12-02 18:07 ` Christoffer Dall 2015-12-02 23:42 ` Mario Smarduch 2015-12-03 9:29 ` Will Deacon 2015-12-03 18:26 ` Mario Smarduch 2015-12-03 18:45 ` Mario Smarduch
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