-----Original Message----- From: Jim Fulton [mailto:jim@digicool.com] Sent: Friday, June 04, 1999 6:40 PM To: Michel Pelletier Cc: 'Tony McDonald'; Zope List Subject: Re: [Zope] Running ZopeHTTPServer and PCGI together = a bad thing?

Michel Pelletier wrote:

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(snip)

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A wafer-thin CGI program is forked for every request, this is used to connect up Apache and the Zope long running process. So yes, this expensive fork happens for every request.

It's not *that* expensive. This is a very thin wrapper.

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It's no different, however, then other CGI overhead.

It's reallu much lower than typical CGI overhead. Most CGI scripts are written using interpreters (e.g. sh, perl, Python). Cranking up an interpreter is much more expensive than cranking up the pcgi_wrapper.

I was sort of thinking about before the actual exec'ing of the CGI program, whether it be fast compiled C or the more common monstrosity of an interpreter (and I don't mean Python either).

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One of these days, someone is going to write a mod_pcgi module for Apache, and take that expensive fork out. For light loads, it's really not noticeable, but for heavy loads, one fork per request gets heavy.

I think a site could sustain a million hits a day using pcgi on moderately fast hardware.

I agree, a million forks per day is not a heavy load, but I bet it's fairly measureable. Tack onto that the need for apache to pre-fork and re-fork servers all the time, and you could hit a pretty hard limit, but I am talking with no actual numbers here, I do seem to remember somewhere statistics on the number of milliseconds a fork took on various platforms and hardware... hmm, where did that go? For linux I seem to remember it being somwhere on the order of 100 or so milliseconds, (I'm reaching) on something like a 486 66mhz machine.

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ZServer is noticably faster in this regard than Apache.

True. An an apache module would definately be a good thing.

Yes, I am curious to see how many milliseconds could be taken off the request round trip time by taking thw whole fork exec cycle out of the request loop? It would probably come into speed with ZServer (if there are enough apaches preforked) since the mechanism at that point is the same, a select() loop. At this point apache's need to context switch would probably even out with ZServer's interpreter overhead, but once again, what the hell do I know?

BTW, ZServer supports PCGI, so you *can* use Apache+PCGI+ZServer. This is useful, for example, if you want to use Apache to do SSL while using ZServer for other HTTP requests and FTP.

Another beauty of apache is that it's got GOBS of little gizmos and knobs on it. And the real workd security issues have been though about by thousands of more experts for apache than ZServer. A double ended light saber no doubt, but I'm sure Darth Fulton could find something to do with them. ;) -Michel

Jim

-- Jim Fulton mailto:jim@digicool.com Python Powered! Technical Director (888) 344-4332 http://www.python.org Digital Creations http://www.digicool.com http://www.zope.org

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