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Re: Issues getting IO times using Schedtimes.stp example script
- From: Josh Stone <jistone at redhat dot com>
- To: Sunny Fugate <fugate at unm dot edu>
- Cc: systemtap at sourceware dot org
- Date: Mon, 30 Jan 2012 15:48:11 -0800
- Subject: Re: Issues getting IO times using Schedtimes.stp example script
- References: <43C46BFF-CB0E-4155-BF0C-6ED3FF698D9B@unm.edu>
On 01/30/2012 03:13 PM, Sunny Fugate wrote:
> I'm having some difficulties in getting one of the examples scripts to
> run. According to the documentation, the kernel.trace("sched_switch")
> probe should expose $prev, $next, and $rq. I've played around with the
> stp script and on my system the $rq variable is never defined.
There used to be a rq parameter, but it was removed from the kernels
2.6.35+ by commit 27a9da65:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=27a9da6538ee18046d7bff8e36a9f783542c54c3
I don't know any other way off-hand to get at the runqueue -- it is held
very secretively in sched internals.
Josh