dtrace discuss - Nov 2005 - Dtrace exiting when system under load

I have been doing sone testing using dtrace and simulating system loads under
various conditions. While I am conducting these tests I also have vmstat, mpstat
or other system monitoring tools running at the same time for comparisons.

Dtrace will exit with the following message:
"dtrace: processing aborted: Abort due to systemic unresponsiveness"

When the system is under a extreme load, Dtrace will exit with the above error,
but vmstat or mpstat will still respond and report.

Is this normal? I would think that Dtrace would chug along collecting and
reporting.

Thanks,

Bob
This message posted from opensolaris.org

On Wed, Nov 30, 2005 at 07:14:01AM -0800, Bob Plymale
wrote:
> I have been doing sone testing using dtrace and simulating system
> loads under various conditions. While I am conducting these tests I
> also have vmstat, mpstat or other system monitoring tools running at
> the same time for comparisons.
> 
> Dtrace will exit with the following message:
> "dtrace: processing aborted: Abort due to systemic
unresponsiveness"
> 
> When the system is under a extreme load, Dtrace will exit with the
> above error, but vmstat or mpstat will still respond and report.
> 
> Is this normal? I would think that Dtrace would chug along collecting
> and reporting.
The problem is that it is possible to craft dtrace enablings which would
wedge the entire system, by causing progress to go so slowly that the
system cannot catch up.  dtrace detects this by having a set of deadman
timers which abort dtrace processing when either:

	1) a periodic timer that fires every second hasn''t been processed in
	   10 seconds, or

	2) the userland consumer, which does a status check every second,
	   hasn''t been heard from in 30 seconds.

You can disable the deadman by enabling destructive actions (-w).

Cheers,
- jonathan

-- 
Jonathan Adams, Solaris Kernel Development

This is normal behavior for dtrace.  If the machine is under heavy  
load, dtrace will disable itself if it thinks it''s causing the machine
to become unresponsive.  You can disable this by using the -w flag.
For further detail you can look at Bryan and Jonathan''s responses in  
http://www.opensolaris.org/jive/thread.jspa?messageID=15073&#15073

Noel :-)


************************************************************************ 
**

"Question all the answers"
On Nov 30, 2005, at 7:14 AM, Bob Plymale wrote:
> I have been doing sone testing using dtrace and simulating system  
> loads under various conditions. While I am conducting these tests I  
> also have vmstat, mpstat or other system monitoring tools running at  
> the same time for comparisons.
>
> Dtrace will exit with the following message:
> "dtrace: processing aborted: Abort due to systemic
unresponsiveness"
>
> When the system is under a extreme load, Dtrace will exit with the  
> above error, but vmstat or mpstat will still respond and report.
>
> Is this normal? I would think that Dtrace would chug along collecting  
> and reporting.
>
> Thanks,
>
> Bob
> This message posted from opensolaris.org
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org