Messages in this thread | | | Date | Sat, 9 May 2009 11:24:31 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] tracing/mm: add page frame snapshot trace |
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* Wu Fengguang <fengguang.wu@intel.com> wrote:
> Hi Ingo, > > On Sat, May 09, 2009 at 02:27:58PM +0800, Ingo Molnar wrote: > > > > * Wu Fengguang <fengguang.wu@intel.com> wrote: > > > > > > So this should be done in cooperation with instrumentation > > > > folks, while improving _all_ of Linux instrumentation in > > > > general. Or, if you dont have the time/interest to work with us > > > > on that, it should not be done at all. Not having the > > > > resources/interest to do something properly is not a license to > > > > introduce further instrumentation crap into Linux. > > > > > > I'd be glad to work with you on the 'object collections' ftrace > > > interfaces. Maybe next month. For now my time have been allocated > > > for the hwpoison work, sorry! > > > > No problem - our offer still stands: we are glad to help out with > > the instrumentation side bits. We'll even write all the patches for > > you, just please help us out with making it maximally useful to > > _you_ :-) > > Thank you very much! > > The good fact is, 2/3 of the code and experiences can be reused. > > > Find below a first prototype patch written by Steve yesterday and > > tidied up a bit by me today. It can also be tried on latest -tip: > > > > http://people.redhat.com/mingo/tip.git/README > > > > This patch adds the first version of the 'object collections' > > instrumentation facility under /debug/tracing/objects/mm/. It has a > > single control so far, a 'number of pages to dump' trigger file: > > > > To dump 1000 pages to the trace buffers, do: > > > > echo 1000 > /debug/tracing/objects/mm/pages/trigger > > > > To dump all pages to the trace buffers, do: > > > > echo -1 > /debug/tracing/objects/mm/pages/trigger > > That is not too intuitive, I'm afraid.
This was just a first-level approximation - and it matches the usual "0xffffffff means infinite" idiom.
How about changing it from 'trigger' to 'dump_range':
echo "*" > /debug/tracing/objects/mm/pages/dump_range
being a shortcut for 'dump all'?
And:
echo "1000 2000" > /debug/tracing/objects/mm/pages/dump_range
?
The '1000' is the offset where the dumping starts, and 2000 is the size of the dump.
Ingo
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