[Seaside] Getting profiling info from Seaside in a VW environment..

Lukas Renggli renggli at gmail.com
Sat Jan 28 10:29:45 CET 2006

> > Since I am currently working on the VW port of 2.6a2 I had a look
> > to the profiling feature. It's quite easy to integrate and it will
> > be included in the next port.
> >
> > A question though.
> >
> > I noticed that profiling is only available for the rendering phase.
> > Sure, this is useful, but not as quite useful as profiling the
> > callback
> > phase. Has anything tried for profiling the callback phase ?
> It's actually harder to do than you would think, because often the
> callback phase involves the invocation of one or more continuations -
> which means that the stack is really messy.  Squeak's profiler,
> anyway, doesn't have an easy time with that.  I agree that it would
> be very useful, however, if someone finds a clever way to do it.

I have written a decorator that logs a lot of interesting information
(in an extended common-log format) for the rendering and the
callback-phase, this includes simple profiling information. For the
callbacks I had to do some fancy continuation tricks, but it works.
The relevant piece of code is the one below (ugly):

processCallbackStream: aStream
	| timing continuation |
	timing := Time millisecondClockValue.
	continuation := self session instVarNamed: 'escapeContinuation'.
	self session instVarNamed: 'escapeContinuation' put: [ :value |
			logRequest: self session currentRequest nativeRequest
			response: value kind: #callback
			time: Time millisecondClockValue - timing.
		continuation value: value ].
	^super processCallbackStream: aStream.

The timing is not entirely correct, but I guess it should give a
figure somewhere close to the real value. If necessary I can publish
the whole code, but I have to negotiate with netstyle.ch first ;-)


Lukas Renggli

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