[Seaside] [BUG] VW High load problem

[Avi Bryant]

Hi Roger,

Thanks for the report.  That's a rather odd bug -  I've certainly never
seen anything like it happen in Squeak.

I'm pretty swamped for the next few days but I'll work on reproducing and
hopefully fixing this some time early next week.

Incidentally in my tests (with Squeak, on an Athlon 1.4Ghz), I
typically see closer to 50 requests per second.  It's hard to know how
much of that difference is the hardware, how much is the VW port, etc.

On Thu, 2 Oct 2003, Roger Whitney wrote:

> I was trying to see what sort of load Seaside running in VW could
> handle. I used the following code to send n sequential requests for the
> same application.
>
> n := 40.
> Time  millisecondsToRun:[n timesRepeat:
> 	[client :=HttpClient new.
> 	client get: 'http://localhost:8008/servlet/SeasideServlet/counter/']]
>
> When n is high enough the server often throws an exception. The size of
> n depends on the hardware speed the server is running on and which page
> is being requested. On a 400 MHz PowerBook G4 requesting the store
> example (which needs a few changes to run in VW) when n is 10 the
> exception is often triggered. When I look at the stack trace I find
> that in the following method at one point copy is an integer and obj is
> a WVStateHolder. This is a problem as snapshot:isIdenticalTo:
> compares the instance variable of the integer to that of WVStateHolder.
> This is a random bug. However if you set n = 40 it has a very high
> probability of occurring.
>
> WAStateRegistry>>snapshot
> 	| snapshot |
> 	snapshot := SeasidePlatformSupport weakDictionaryOfSize: objects size.
> 	objects keysAndValuesDo:
> 		[:obj :copy|
> 		(self snapshot: copy isIdenticalTo: obj)
> 			ifTrue: [snapshot at: obj put: copy]
> 			ifFalse: [snapshot at: obj put: obj shallowCopy]].
> 	^ snapshot
>
> By the way I can get 9 pages per second on the 400 MHZ G4 PowerBook
> when requesting the store example from a separate machine on the same
> local network.
> ----
> Roger Whitney              Department of Computer Science
> whitney at cs.sdsu.edu        San Diego State University
> http://www.eli.sdsu.edu/   San Diego, CA 92182-7720
> (619) 583-1978
> (619) 594-3535 (office)
> (619) 594-6746 (fax)
>
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