[Seaside] Re: Are Collections threadsafe?
philippe.marschall at gmail.com
Wed Feb 27 05:56:59 UTC 2008
2008/2/27, Andreas Raab <andreas.raab at gmx.de>:
> goran at krampe.se wrote:
> > I didn't imply the problems have been undetected - I just meant that
> > they have gone undetected for a looong time. And most users deploy stuff
> > with Squeak and do just fine. That is all I am saying.
> The real trouble is that some of the people (like Philippe) that are
> closest to the point of the problem end up complaining in general
> instead of gathering valuable data. Basically it's all flawed logic of
> the form "clearly, our code can't possibly be wrong so the VM must be
> broken and why don't you guys just get your act together and fix it".
> What people *really* need to do in such a situation is to gather as much
> data as possible. If you can still save the image, save it. If you can
> still get a bunch of stack traces, get them. Attach gdb to the VM and do
> a printAllStacks() - this is probably the most important information you
> get in a situation like this (at Qwaq, we have hooked this up to a USR1
> signal so that when we need to restart the servers we first get a full
> stack trace and then restart the images just in case).
That's simple if your image blocks. If your image doesn't blocks but
the behavior you get looks as if your critical sections are not
critical what do you do then? Attach gdb at random points in time?
Would that really help?
> Once you have gathered all that information, post it to Squeak-dev.
> There are actually people out there who care about it. They just don't
> care very much about editorial comments of the form "TEH SQUEAK SUCKZ!".
> If you want a solution, then provide the input that helps other people
> resolving your problem. The short form of that equation is:
> complaints == no data
> no data == no solution
> And if you keep this in mind (and your frustration to a minimum) you
> will likely find that *with* data the probability of actually fixing
> your problems goes up dramatically.
> > Of course we should fix it. But we should also not scare people into
> > thinking that Semaphores are *totally* broken and that Squeak is total
> > crap when it comes to concurrency. :)
> Absolutely. At Qwaq, we routinely run servers with hundreds of
> concurrent connections piping through gigabytes of data per day.
> - Andreas
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