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X-Authentication-Warning: slinky.cs.nyu.edu: pechtcha owned process doing -bs
Date: Tue, 13 Jul 2004 18:20:19 -0400 (EDT)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: Yitzchak Scott-Thoennes <sthoenna AT efn DOT org>
cc: cygwin AT cygwin DOT com
Subject: Re: cat /proc/registry/HKEY_PERFOMANCE_DATA/@ hangs
In-Reply-To: <20040713220503.GA2896@efn.org>
Message-ID: <Pine.GSO.4.58.0407131812080.29800@slinky.cs.nyu.edu>
References: <NUTMEGUIP5RxDgQDJcu00000853 AT NUTMEG DOT CAM DOT ARTIMI DOT COM> <Pine DOT GSO DOT 4 DOT 58 DOT 0407131204160 DOT 29800 AT slinky DOT cs DOT nyu DOT edu> <20040713220503 DOT GA2896 AT efn DOT org>
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On Tue, 13 Jul 2004, Yitzchak Scott-Thoennes wrote:

> On Tue, Jul 13, 2004 at 12:21:50PM -0400, Igor Pechtchanski wrote:
> >       bufalloc = 0;
> >       do
> >         {
> > ==>       bufalloc += 1000;
>
> >
> > I have a theory that the performance data may be added in chunks larger
> > than 1000 bytes, so the fhandler just can't keep up with the amount of
> > data, and loops indefinitely.  Since you intend to build the DLL from CVS,
> > you're probably in the best position to check whether this theory is true
> > (by either just upping the increment amount to something like 5000, or
> > even doubling the buffer size on each iteration).
>
> Perhaps bufalloc += max(bufalloc, 1000);

Sorry, but no.  This will do nothing for the original problem.  The idea
was that at some point you need the rate of buffer size increase to
overtake the rate of performance data generation.  If performance data is
generated faster than 1000 bytes per query, and adding 1000 bytes isn't
enough, adding *at most* 1000 bytes (as you suggested) is strictly less
effective.  I suggested a linear function with a steeper slope (which may
not be enough) or an exponential, which will definitely be enough, but may
introduce huge buffers.

I'm going to build the DLL from CVS now to test the theory.  If it is
confirmed, then we can talk about a good buffer size increment function
(probably on cygwin-developers, though).
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_		pechtcha AT cs DOT nyu DOT edu
ZZZzz /,`.-'`'    -.  ;-;;,_		igor AT watson DOT ibm DOT com
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"I have since come to realize that being between your mentor and his route
to the bathroom is a major career booster."  -- Patrick Naughton

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