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RE: MAXACTION exceeded error while using systemtap
- From: "Stone, Joshua I" <joshua dot i dot stone at intel dot com>
- To: "Frank Ch. Eigler" <fche at redhat dot com>
- Cc: <systemtap at sources dot redhat dot com>
- Date: Tue, 6 Dec 2005 13:56:02 -0800
- Subject: RE: MAXACTION exceeded error while using systemtap
Frank Ch. Eigler wrote:
> Bug #1866 links to #1884, which does that.
Oops, sorry, I interpreted the "duplicate of" message backwards...
>> At the very least, we should have something along the Dtrace's
>> printa(): [...] Bug #1121 seems applicable to this problem [...]
>
> The print/printf routines have worked for a few weeks now. I don't
> know whether Graydon intends to extend them to print arrays also.
The bug mentions printing entire arrays - that is what I was referring
to.
> I am unsure about how to estimate the very real cost of an array-print
> operator. Calling it approximately zero would make it into a
> something like a DoS vector. Intuitively, it should be proportional
> to the amount of output generated, so it relates to bug #1885.
I guess it's a question of the purpose of MAXACTION. My understanding
is that it is meant to avoid infinite loops/recursion. In this sense,
giving printa a cost of one is ok, because the size of the array is
bound by MAXMAPENTRIES.
If you mean for MAXACTION to also provide a bound on time, then I tend
to agree with your comment #4 on 1884 - we need a way to determine a
more representative MAXACTION.
Josh