Date: Thu, 15 Jul 1999 12:35:00 -0700 (PDT) From: Tani Hosokawa <unknown@riverstyx.net> To: David Schwartz <davids@webmaster.com> Cc: lh@aus.org, chat@FreeBSD.ORG Subject: RE: Known MMAP() race conditions ... ? Message-ID: <Pine.LNX.4.10.9907151216050.10288-100000@avarice.riverstyx.net> In-Reply-To: <000001becef6$6853c670$021d85d1@youwant.to>
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On Thu, 15 Jul 1999, David Schwartz wrote: > > It's one-process-per-request model is atrocious. > > Let me retract this statement, because it's not really fair. > > Apache has done an amazing job of getting very good performance on a wide > variety of platforms. The one-process-per-request model does create > problems, but they're usually in special cases, like when you're using lots > of perl CGIs and mod_perl. If you're just talking about the big fat memory footprints, you can do what the performance tuning guide suggests and put a proxy (like Squid) in front of it. I'm using mod_perl to serve a similar amount of requests I'd be able to do with static data. You've also brought up another good point -- portability between platforms can be increased by using a good threading model. Like, with the apr project. And it's easier to code for. Time to market is a major factor in a lot of decisions, and if it's going to be harder to code for X platform because it doesn't support the easiest model well, then it might be better to go with Y platform that has some disadvantages comparitively, but kicks ass on the issue that's being addressed. > But if you're going to change it, and lose that, you should change it in > favor of a clearly better model. And I'm not sure one-thread-per-request is > clearly better. Per-thread is clearly better, for a number of reasons. o shared address space being one of them o better caching of the filesystem o context switches between threads are generally less expensive than context switches between processes o easy upgrade path from per-process to per-thread for user modules --- tani hosokawa river styx internet To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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