[PATCH OSSTEST] ts-debian-install: increase time allowed for xen-create-image

[PATCH OSSTEST] ts-debian-install: increase time allowed for xen-create-image

[Ian Campbell]

This step is consistently timing out when run on cubietruck-*. Judging
from the logs it appears to be completing during the 30s slack added
by tcmdex (i.e. after the timeout message the rest of the output
appears in the test step log).

Looking at the results on arndale-* (which looks to pass reasonably
reliably) I see that the regular test-armhf-armhf-xl job takes around
550s to do the xen-create-image while test-armhf-armhf-xl-rtds
typically takes around 1100s (twice as long).

On cubietruck-braque test-armhf-armhf-xl uses 900s. One could
therefore extrapolate that test-armhf-armhf-xl-rtds might need more
than 1800s and not be too surprised that it appears to need something
a bit more than 2000s in practice. 2500s seems like sufficient
headroom.

For comparisson with arm on x86 godello takes around 210s in the
normal case and 680s with RTDS (>3x slower) while nocera takes 265s
and 640s (2.4x). (Those are from nearby but not identical flights in
order to match up the host).

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Meng Xu <mengxu@cis.upenn.edu>

Dario, Meng, I suppose a 2-3x slow down with RTDS on a dom0 operation
(with no domains running) such as xen-create-image is not unexpected?
---
 ts-debian-install | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ts-debian-install b/ts-debian-install
index f42edbf..2a7331d 100755
--- a/ts-debian-install
+++ b/ts-debian-install
@@ -95,7 +95,7 @@ END
             $initrd_opt \\
             $archarg
 END
-    target_cmd_root($ho, $cmd, 2000);
+    target_cmd_root($ho, $cmd, 2500);
 
     my $cfg= "/etc/xen/$gho->{Name}.cfg";
     store_runvar("$gho->{Guest}_cfgpath", $cfg);
-- 
2.6.1

Re: [PATCH OSSTEST] ts-debian-install: increase time allowed for xen-create-image

[Dario Faggioli]

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On Fri, 2016-01-15 at 13:35 +0000, Ian Campbell wrote:
> This step is consistently timing out when run on cubietruck-*.
> Judging
> from the logs it appears to be completing during the 30s slack added
> by tcmdex (i.e. after the timeout message the rest of the output
> appears in the test step log).
> 
> Looking at the results on arndale-* (which looks to pass reasonably
> reliably) I see that the regular test-armhf-armhf-xl job takes around
> 550s to do the xen-create-image while test-armhf-armhf-xl-rtds
> typically takes around 1100s (twice as long).
> 
> On cubietruck-braque test-armhf-armhf-xl uses 900s. One could
> therefore extrapolate that test-armhf-armhf-xl-rtds might need more
> than 1800s and not be too surprised that it appears to need something
> a bit more than 2000s in practice. 2500s seems like sufficient
> headroom.
> 
> For comparisson with arm on x86 godello takes around 210s in the
> normal case and 680s with RTDS (>3x slower) while nocera takes 265s
> and 640s (2.4x). (Those are from nearby but not identical flights in
> order to match up the host).
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>

> ---
> Dario, Meng, I suppose a 2-3x slow down with RTDS on a dom0 operation
> (with no domains running) such as xen-create-image is not unexpected?
>
Yes, as of now, I think it is. RTDS' default scheduling parameters
throttle domains' vcpus to max 40% of CPU, non work conserving mode
(i.e.m, they only consume up to that much even if there is idle time).

I think this will have to change at some point, but for now, slowdowns
for operation like the ones in xen-create-image are to be expected, and
this patch looks therefore ok to me.

Thanks and Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: [PATCH OSSTEST] ts-debian-install: increase time allowed for xen-create-image

[Ian Campbell]

On Fri, 2016-01-15 at 15:44 +0100, Dario Faggioli wrote:
> On Fri, 2016-01-15 at 13:35 +0000, Ian Campbell wrote:
> > This step is consistently timing out when run on cubietruck-*.
> > Judging
> > from the logs it appears to be completing during the 30s slack added
> > by tcmdex (i.e. after the timeout message the rest of the output
> > appears in the test step log).
> > 
> > Looking at the results on arndale-* (which looks to pass reasonably
> > reliably) I see that the regular test-armhf-armhf-xl job takes around
> > 550s to do the xen-create-image while test-armhf-armhf-xl-rtds
> > typically takes around 1100s (twice as long).
> > 
> > On cubietruck-braque test-armhf-armhf-xl uses 900s. One could
> > therefore extrapolate that test-armhf-armhf-xl-rtds might need more
> > than 1800s and not be too surprised that it appears to need something
> > a bit more than 2000s in practice. 2500s seems like sufficient
> > headroom.
> > 
> > For comparisson with arm on x86 godello takes around 210s in the
> > normal case and 680s with RTDS (>3x slower) while nocera takes 265s
> > and 640s (2.4x). (Those are from nearby but not identical flights in
> > order to match up the host).
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> > 
> Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
> 
> > ---
> > Dario, Meng, I suppose a 2-3x slow down with RTDS on a dom0 operation
> > (with no domains running) such as xen-create-image is not unexpected?
> > 
> Yes, as of now, I think it is. RTDS' default scheduling parameters
> throttle domains' vcpus to max 40% of CPU, non work conserving mode
> (i.e.m, they only consume up to that much even if there is idle time).

Thanks. 40% seems to correlate to the 2-3x slowdown we are seeing.
> 
> I think this will have to change at some point, but for now, slowdowns
> for operation like the ones in xen-create-image are to be expected, and
> this patch looks therefore ok to me.
> 
> Thanks and Regards,
> Dario

Re: [PATCH OSSTEST] ts-debian-install: increase time allowed for xen-create-image

[Ian Jackson]

Ian Campbell writes ("[PATCH OSSTEST] ts-debian-install: increase time allowed for xen-create-image"):
> This step is consistently timing out when run on cubietruck-*. Judging
> from the logs it appears to be completing during the 30s slack added
> by tcmdex (i.e. after the timeout message the rest of the output
> appears in the test step log).

Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>