Grasping the concept of Classes & Categories
Daniel Salama
dsalama at user.net
Mon Jun 20 01:48:32 UTC 2005
Chris,
On Jun 17, 2005, at 4:03 PM, Chris Muller wrote:
> Ah well, it sounds like you *do* have a reason to commingle your
> Customers
> then. My answer assumed none, other than code-reuse benefits.
>
>
>> However, given my limited resources for hardware (mainly), I wasn't
>> sure if I could, efficiently, run two Squeak images, each with
>> Seaside listening on different ports and both front-ended by Apache
>> on a single machine. I wasn't sure how two images could run on the
>> same machine in terms of performance, processes, memory, etc.
>> Assuming these would run on a dual-Xeon machine with 2GB RAM, would
>> that be feasible?
>>
>
> That's a valid question. Given your end-goal is to have good-
> performance for
> users of both applications, an equally valid question is; will one
> single-threaded Squeak VM efficiently run both applications?
Eventually, I'll be able to properly architect the system across
multiple machines where Apache, Storage (MySQL and/or GOODS), Squeak,
etc. It's just that for now, all I have is this single machine.
>
> My guess is a dual-Xeon machine with 2GB RAM will not run a single
> Squeak image
> any faster than a single-Xeon machine.
I don't know too much about the behind the scenes of Squeak so I
don't know about its multi-process/multi-threaded capabilities
coexisting with the support provided by the host OS.
>
> For analogy, I currently, this very second as I'm typing, have five
> running
> images on my 768MB 1.3GHz IBM laptop. One of them is listening on two
> different ports, two others are listening on one port each. A
> fourth one is
> not listening but is sending requests to the first three. Millions
> of requests
> are being sent to each other like mad. Windows Task Manager shows
> 100% CPU
> used for the last hour. Meanwhile, I type this e-mail in Mozilla
> and I don't
> even notice a spec of delay between keystrokes or any indication of
> stress.
> The same is true in the fifth Squeak image which is not
> participating in the
> TCP/IP party. That's because they are running on their own OS thread.
That's pretty good. I think that if my apps perform similar to that,
I should be fine for some time.
>
> However, if I try to type in one of the other images that *is*
> sending/receiving requests, I notice little pauses between my
> keystrokes.
> This occurs because each VM runs in but a single thread, and when
> that thread
> is handling a request, my keystrokes and/or the UI updates are
> blocked.
>
> The point is, requests processed by one app will most likely
> temporarily block
> requests for the other app, when both are running in the same
> image. Something
> worth considering for your planning..
I've noticed that when I have taxed a Squeak image running bulk data
transfers using any of the Squeak OODB interfaces (I haven't noticed
the same when doing similar bulk data transfers on MySQL or Postgres)
>
> Of course, if you're restricted on port #'s, that could present its
> own
> challenge..
I guess I could always start Seaside (WAKom) to listen on different
ports and have Apache redirect appropriately.
>
> - Chris
>
Thanks,
Daniel
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