* At a loss: Kernel 2.6.19-rt15 with ixp425
@ 2010-06-08 18:17 Eric W Anderson
2010-06-08 18:37 ` Sven-Thorsten Dietrich
0 siblings, 1 reply; 6+ messages in thread
From: Eric W Anderson @ 2010-06-08 18:17 UTC (permalink / raw)
To: linux-rt-users
[-- Attachment #1: Type: text/plain, Size: 2136 bytes --]
Hello All,
I can't figure out (or haven't figured out) how to get actual high-resolution
timers on the above platform. I'm kind of stuck with 2.6.19, unfortunately.
I've applied the -rt patch to stock 2.6.19, merged in some random patches to
support my hardware, and gotten it to boot. But, here's what confuses me: I
have the hrtimer API, but my actual clock resolution is still shown as 10ms.
root@patty:/# cat /proc/timer_list
Timer List Version: v0.1
HRTIMER_MAX_CLOCK_BASES: 2
now at 2766685920305 nsecs
cpu: 0
clock 0:
.index: 0
.resolution: 10000000 nsecs
.get_time: ktime_get_real
active timers:
clock 1:
.index: 1
.resolution: 10000000 nsecs
.get_time: ktime_get
active timers:
#0: <c4615ec8>, hrtimer_wakeup
# expires at 2766802147358 nsecs [in 116227053 nsecs]
#1: <c4615ec8>, it_real_fn
# expires at 2767494816966 nsecs [in 808896661 nsecs]
#2: <c4615ec8>, it_real_fn
# expires at 3642163204498 nsecs [in 875477284193 nsecs]
#3: <c4615ec8>, it_real_fn
# expires at 3643403169278 nsecs [in 876717248973 nsecs]
Additionally, I don't see CONFIG_HIGH_RES_TIMERS anywhere in my kernel
menuconfig. I've added a patch from Kevin Hilman and Milan Svoboda
(http://lkml.indiana.edu/hypermail/linux/kernel/0607.1/2343.html) which
purports to enable a high-resolution clock event source for this board, but
that doesn't seem to change anything.
I think I don't properly understand the preempt_rt / hrtimers /
board-specific-bits ecosystem here. What are the bits and pieces I need in
order to have high-resolution timers on this platform?
Many, many thanks,
Eric Anderson
--
Eric W. Anderson University of Colorado
eric.anderson@colorado.edu Dept. of Computer Science
phone: +1-720-984-8864 Systems Research Lab - ECCR 1B54
PGP key fingerprints:
personal: 1BD4 CFCE 8B59 8D6E EA3E EBD5 4DC9 3E61 656C 462B
academic: D3C5 D6FF EDED 9F1F C36D 53A3 74B7 53A6 3C74 5F12
[-- Attachment #2: Digital signature --]
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: At a loss: Kernel 2.6.19-rt15 with ixp425 2010-06-08 18:17 At a loss: Kernel 2.6.19-rt15 with ixp425 Eric W Anderson @ 2010-06-08 18:37 ` Sven-Thorsten Dietrich 2010-06-08 19:32 ` Eric W Anderson 0 siblings, 1 reply; 6+ messages in thread From: Sven-Thorsten Dietrich @ 2010-06-08 18:37 UTC (permalink / raw) To: Eric W Anderson; +Cc: linux-rt-users On Tue, 2010-06-08 at 12:17 -0600, Eric W Anderson wrote: > Hello All, Hi Eric, 2.6.19 is very very old. What is preventing you from a Kernel upgrade? Sven > > I can't figure out (or haven't figured out) how to get actual high-resolution > timers on the above platform. I'm kind of stuck with 2.6.19, unfortunately. > I've applied the -rt patch to stock 2.6.19, merged in some random patches to > support my hardware, and gotten it to boot. But, here's what confuses me: I > have the hrtimer API, but my actual clock resolution is still shown as 10ms. > > root@patty:/# cat /proc/timer_list > Timer List Version: v0.1 > HRTIMER_MAX_CLOCK_BASES: 2 > now at 2766685920305 nsecs > > cpu: 0 > clock 0: > .index: 0 > .resolution: 10000000 nsecs > .get_time: ktime_get_real > active timers: > clock 1: > .index: 1 > .resolution: 10000000 nsecs > .get_time: ktime_get > active timers: > #0: <c4615ec8>, hrtimer_wakeup > # expires at 2766802147358 nsecs [in 116227053 nsecs] > #1: <c4615ec8>, it_real_fn > # expires at 2767494816966 nsecs [in 808896661 nsecs] > #2: <c4615ec8>, it_real_fn > # expires at 3642163204498 nsecs [in 875477284193 nsecs] > #3: <c4615ec8>, it_real_fn > # expires at 3643403169278 nsecs [in 876717248973 nsecs] > > Additionally, I don't see CONFIG_HIGH_RES_TIMERS anywhere in my kernel > menuconfig. I've added a patch from Kevin Hilman and Milan Svoboda > (http://lkml.indiana.edu/hypermail/linux/kernel/0607.1/2343.html) which > purports to enable a high-resolution clock event source for this board, but > that doesn't seem to change anything. > > I think I don't properly understand the preempt_rt / hrtimers / > board-specific-bits ecosystem here. What are the bits and pieces I need in > order to have high-resolution timers on this platform? > > Many, many thanks, > Eric Anderson > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: At a loss: Kernel 2.6.19-rt15 with ixp425 2010-06-08 18:37 ` Sven-Thorsten Dietrich @ 2010-06-08 19:32 ` Eric W Anderson 2010-06-09 17:02 ` Sven-Thorsten Dietrich 0 siblings, 1 reply; 6+ messages in thread From: Eric W Anderson @ 2010-06-08 19:32 UTC (permalink / raw) To: Sven-Thorsten Dietrich; +Cc: linux-rt-users [-- Attachment #1: Type: text/plain, Size: 3097 bytes --] Hi Sven, The device manufacturer has made some kernel modifications to support their board, and those are specific to 2.6.19. (In fact, they're specific to 2.6.19.2 OpenWRT patches). There's also a large driver which is appropriate for an old kernel but would need some re-engineering to deal with API changes in 2.6.20 or 2.6.21, I believe. So, if getting high-resolution timing with this kernel is going to be a nightmare, I can try taking on a newer kernel. But it'll be an ordeal. -Eric Thus spake Sven-Thorsten Dietrich (thebigcorporation@gmail.com): > On Tue, 2010-06-08 at 12:17 -0600, Eric W Anderson wrote: > > Hello All, > > Hi Eric, > > 2.6.19 is very very old. > > What is preventing you from a Kernel upgrade? > > Sven > > > > > > I can't figure out (or haven't figured out) how to get actual high-resolution > > timers on the above platform. I'm kind of stuck with 2.6.19, unfortunately. > > I've applied the -rt patch to stock 2.6.19, merged in some random patches to > > support my hardware, and gotten it to boot. But, here's what confuses me: I > > have the hrtimer API, but my actual clock resolution is still shown as 10ms. > > > > root@patty:/# cat /proc/timer_list > > Timer List Version: v0.1 > > HRTIMER_MAX_CLOCK_BASES: 2 > > now at 2766685920305 nsecs > > > > cpu: 0 > > clock 0: > > .index: 0 > > .resolution: 10000000 nsecs > > .get_time: ktime_get_real > > active timers: > > clock 1: > > .index: 1 > > .resolution: 10000000 nsecs > > .get_time: ktime_get > > active timers: > > #0: <c4615ec8>, hrtimer_wakeup > > # expires at 2766802147358 nsecs [in 116227053 nsecs] > > #1: <c4615ec8>, it_real_fn > > # expires at 2767494816966 nsecs [in 808896661 nsecs] > > #2: <c4615ec8>, it_real_fn > > # expires at 3642163204498 nsecs [in 875477284193 nsecs] > > #3: <c4615ec8>, it_real_fn > > # expires at 3643403169278 nsecs [in 876717248973 nsecs] > > > > Additionally, I don't see CONFIG_HIGH_RES_TIMERS anywhere in my kernel > > menuconfig. I've added a patch from Kevin Hilman and Milan Svoboda > > (http://lkml.indiana.edu/hypermail/linux/kernel/0607.1/2343.html) which > > purports to enable a high-resolution clock event source for this board, but > > that doesn't seem to change anything. > > > > I think I don't properly understand the preempt_rt / hrtimers / > > board-specific-bits ecosystem here. What are the bits and pieces I need in > > order to have high-resolution timers on this platform? > > > > Many, many thanks, > > Eric Anderson > > > > > > -- Eric W. Anderson University of Colorado eric.anderson@colorado.edu Dept. of Computer Science phone: +1-720-984-8864 Systems Research Lab - ECCR 1B54 PGP key fingerprints: personal: 1BD4 CFCE 8B59 8D6E EA3E EBD5 4DC9 3E61 656C 462B academic: D3C5 D6FF EDED 9F1F C36D 53A3 74B7 53A6 3C74 5F12 [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 198 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: At a loss: Kernel 2.6.19-rt15 with ixp425 2010-06-08 19:32 ` Eric W Anderson @ 2010-06-09 17:02 ` Sven-Thorsten Dietrich 2010-06-09 18:50 ` Xianghua Xiao 0 siblings, 1 reply; 6+ messages in thread From: Sven-Thorsten Dietrich @ 2010-06-09 17:02 UTC (permalink / raw) To: Eric W Anderson; +Cc: linux-rt-users On Tue, 2010-06-08 at 13:32 -0600, Eric W Anderson wrote: > Hi Sven, > > The device manufacturer has made some kernel modifications to support their > board, and those are specific to 2.6.19. (In fact, they're specific to > 2.6.19.2 OpenWRT patches). There's also a large driver which is appropriate > for an old kernel but would need some re-engineering to deal with API changes > in 2.6.20 or 2.6.21, I believe. > > So, if getting high-resolution timing with this kernel is going to be a > nightmare, I can try taking on a newer kernel. But it'll be an ordeal. > Don't know really what to say. With the device manufacturer not pushing / maintaining code upstream, that sounds like a non-starter already. The ixp425 is supported by folks like MontaVista, maybe Wind River iirc. The former has had some sort of HRT support for a long time, it might get you the functionality you need. But in any case, I'd try and walk the drivers forward, rather than try to back-port HRT. You're unlikely to get much support for such an old Kernel if you run into other issues, so the more up to date you can get, the better. Good luck. Sven > -Eric > > > Thus spake Sven-Thorsten Dietrich (thebigcorporation@gmail.com): > > > On Tue, 2010-06-08 at 12:17 -0600, Eric W Anderson wrote: > > > Hello All, > > > > Hi Eric, > > > > 2.6.19 is very very old. > > > > What is preventing you from a Kernel upgrade? > > > > Sven > > > > > > > > > > I can't figure out (or haven't figured out) how to get actual high-resolution > > > timers on the above platform. I'm kind of stuck with 2.6.19, unfortunately. > > > I've applied the -rt patch to stock 2.6.19, merged in some random patches to > > > support my hardware, and gotten it to boot. But, here's what confuses me: I > > > have the hrtimer API, but my actual clock resolution is still shown as 10ms. > > > > > > root@patty:/# cat /proc/timer_list > > > Timer List Version: v0.1 > > > HRTIMER_MAX_CLOCK_BASES: 2 > > > now at 2766685920305 nsecs > > > > > > cpu: 0 > > > clock 0: > > > .index: 0 > > > .resolution: 10000000 nsecs > > > .get_time: ktime_get_real > > > active timers: > > > clock 1: > > > .index: 1 > > > .resolution: 10000000 nsecs > > > .get_time: ktime_get > > > active timers: > > > #0: <c4615ec8>, hrtimer_wakeup > > > # expires at 2766802147358 nsecs [in 116227053 nsecs] > > > #1: <c4615ec8>, it_real_fn > > > # expires at 2767494816966 nsecs [in 808896661 nsecs] > > > #2: <c4615ec8>, it_real_fn > > > # expires at 3642163204498 nsecs [in 875477284193 nsecs] > > > #3: <c4615ec8>, it_real_fn > > > # expires at 3643403169278 nsecs [in 876717248973 nsecs] > > > > > > Additionally, I don't see CONFIG_HIGH_RES_TIMERS anywhere in my kernel > > > menuconfig. I've added a patch from Kevin Hilman and Milan Svoboda > > > (http://lkml.indiana.edu/hypermail/linux/kernel/0607.1/2343.html) which > > > purports to enable a high-resolution clock event source for this board, but > > > that doesn't seem to change anything. > > > > > > I think I don't properly understand the preempt_rt / hrtimers / > > > board-specific-bits ecosystem here. What are the bits and pieces I need in > > > order to have high-resolution timers on this platform? > > > > > > Many, many thanks, > > > Eric Anderson > > > > > > > > > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: At a loss: Kernel 2.6.19-rt15 with ixp425 2010-06-09 17:02 ` Sven-Thorsten Dietrich @ 2010-06-09 18:50 ` Xianghua Xiao 2010-06-10 2:25 ` Sven-Thorsten Dietrich 0 siblings, 1 reply; 6+ messages in thread From: Xianghua Xiao @ 2010-06-09 18:50 UTC (permalink / raw) To: Sven-Thorsten Dietrich; +Cc: Eric W Anderson, linux-rt-users On Wed, Jun 9, 2010 at 12:02 PM, Sven-Thorsten Dietrich <thebigcorporation@gmail.com> wrote: > On Tue, 2010-06-08 at 13:32 -0600, Eric W Anderson wrote: >> Hi Sven, >> >> The device manufacturer has made some kernel modifications to support their >> board, and those are specific to 2.6.19. (In fact, they're specific to >> 2.6.19.2 OpenWRT patches). There's also a large driver which is appropriate >> for an old kernel but would need some re-engineering to deal with API changes >> in 2.6.20 or 2.6.21, I believe. >> >> So, if getting high-resolution timing with this kernel is going to be a >> nightmare, I can try taking on a newer kernel. But it'll be an ordeal. >> > > Don't know really what to say. > > With the device manufacturer not pushing / maintaining code upstream, > that sounds like a non-starter already. > > The ixp425 is supported by folks like MontaVista, maybe Wind River iirc. > > The former has had some sort of HRT support for a long time, it might > get you the functionality you need. > > But in any case, I'd try and walk the drivers forward, rather than try > to back-port HRT. > > You're unlikely to get much support for such an old Kernel if you run > into other issues, so the more up to date you can get, the better. > > Good luck. > > Sven > >> -Eric >> >> >> Thus spake Sven-Thorsten Dietrich (thebigcorporation@gmail.com): >> >> > On Tue, 2010-06-08 at 12:17 -0600, Eric W Anderson wrote: >> > > Hello All, >> > >> > Hi Eric, >> > >> > 2.6.19 is very very old. >> > >> > What is preventing you from a Kernel upgrade? >> > >> > Sven >> > >> > >> > > >> > > I can't figure out (or haven't figured out) how to get actual high-resolution >> > > timers on the above platform. I'm kind of stuck with 2.6.19, unfortunately. >> > > I've applied the -rt patch to stock 2.6.19, merged in some random patches to >> > > support my hardware, and gotten it to boot. But, here's what confuses me: I >> > > have the hrtimer API, but my actual clock resolution is still shown as 10ms. >> > > >> > > root@patty:/# cat /proc/timer_list >> > > Timer List Version: v0.1 >> > > HRTIMER_MAX_CLOCK_BASES: 2 >> > > now at 2766685920305 nsecs >> > > >> > > cpu: 0 >> > > clock 0: >> > > .index: 0 >> > > .resolution: 10000000 nsecs >> > > .get_time: ktime_get_real >> > > active timers: >> > > clock 1: >> > > .index: 1 >> > > .resolution: 10000000 nsecs >> > > .get_time: ktime_get >> > > active timers: >> > > #0: <c4615ec8>, hrtimer_wakeup >> > > # expires at 2766802147358 nsecs [in 116227053 nsecs] >> > > #1: <c4615ec8>, it_real_fn >> > > # expires at 2767494816966 nsecs [in 808896661 nsecs] >> > > #2: <c4615ec8>, it_real_fn >> > > # expires at 3642163204498 nsecs [in 875477284193 nsecs] >> > > #3: <c4615ec8>, it_real_fn >> > > # expires at 3643403169278 nsecs [in 876717248973 nsecs] >> > > >> > > Additionally, I don't see CONFIG_HIGH_RES_TIMERS anywhere in my kernel >> > > menuconfig. I've added a patch from Kevin Hilman and Milan Svoboda >> > > (http://lkml.indiana.edu/hypermail/linux/kernel/0607.1/2343.html) which >> > > purports to enable a high-resolution clock event source for this board, but >> > > that doesn't seem to change anything. >> > > >> > > I think I don't properly understand the preempt_rt / hrtimers / >> > > board-specific-bits ecosystem here. What are the bits and pieces I need in >> > > order to have high-resolution timers on this platform? >> > > >> > > Many, many thanks, >> > > Eric Anderson >> > > >> > > >> > >> > >> > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > while upgrading to newer kernel sounds great, which I just did(from 2.6.18rt to 2.6.33rt), the newer kernel sometimes does not perform as well as older ones(plus it's also bloated), esp in embedded products. In my case, we got a slower product with the newer kernel, the 'worse' performance happened immediately when CFS was added. Even after a long time debugging and tweaking, it's still there. xianghua -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: At a loss: Kernel 2.6.19-rt15 with ixp425 2010-06-09 18:50 ` Xianghua Xiao @ 2010-06-10 2:25 ` Sven-Thorsten Dietrich 0 siblings, 0 replies; 6+ messages in thread From: Sven-Thorsten Dietrich @ 2010-06-10 2:25 UTC (permalink / raw) To: Xianghua Xiao; +Cc: Eric W Anderson, linux-rt-users On Wed, 2010-06-09 at 13:50 -0500, Xianghua Xiao wrote: > while upgrading to newer kernel sounds great, which I just did(from > 2.6.18rt to 2.6.33rt), the newer kernel sometimes does not perform as > well as older ones(plus it's also bloated), esp in embedded products. > In my case, we got a slower product with the newer kernel, the 'worse' > performance happened immediately when CFS was added. Even after a long > time debugging and tweaking, it's still there. > > xianghua I am sure if you provided some specific code or performance data to substantiate that regression someone here (or on LKML) would take interest. Regards Sven ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-06-10 2:25 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2010-06-08 18:17 At a loss: Kernel 2.6.19-rt15 with ixp425 Eric W Anderson 2010-06-08 18:37 ` Sven-Thorsten Dietrich 2010-06-08 19:32 ` Eric W Anderson 2010-06-09 17:02 ` Sven-Thorsten Dietrich 2010-06-09 18:50 ` Xianghua Xiao 2010-06-10 2:25 ` Sven-Thorsten Dietrich
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