Date: Mon, 20 Dec 1999 17:43:41 -0800 From: Jason Evans <jasone@canonware.com> To: Chris Sedore <cmsedore@maxwell.syr.edu> Cc: Jason Evans <jasone@canonware.com>, hackers@FreeBSD.ORG Subject: Re: Practical limit for number of TCP connections? Message-ID: <19991220174341.A39990@sturm.canonware.com> In-Reply-To: <Pine.BSF.4.05.9912201950190.82375-100000@qwerty.maxwell.syr.edu>; from cmsedore@maxwell.syr.edu on Mon, Dec 20, 1999 at 08:24:28PM -0500 References: <19991220164517.F26743@sturm.canonware.com> <Pine.BSF.4.05.9912201950190.82375-100000@qwerty.maxwell.syr.edu>
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On Mon, Dec 20, 1999 at 08:24:28PM -0500, Chris Sedore wrote: > On Mon, 20 Dec 1999, Jason Evans wrote: > > I disagree with your assessment that scalability of one thread per > > connection is proportional to the quality of the threads implementation. > > An ideal threaded program would have exactly as many threads as available > > processors, and the threads would always be runnable. Of course, > > real-world applications almost never work that way, but the goal of a > > programmer should be to have as few threads as possible while still > > achieving maximal parallelism. If connection scalability is an issue, > > using one thread per connection ignores a critical aspect of high > > performance threaded application design. > > I don't disagree with any of what you have written. I'd expect you to > concede that it is true that the scalability is proportional. That is, > LinuxThreads (that is, rfork()) is probably not anything like optimally > scalable, but something like the last FreeBSD KSE model that I saw > bouncing around on -arch would do alot better. Yes, LinuxThreads has a number of scalability problems that make using even a relatively small number of threads perform quite poorly, especially if there are multiple multi-threaded applications running on the same machine. I have serious issues with the 1:1 approach that LinuxThreads uses, because it fails to perform reasonably for anything but a very constrained set of multi-threaded programming models. Jason To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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