Date: Sun, 19 Dec 1999 23:39:33 +0900 From: "Daniel C. Sobral" <dcs@newsguy.com> To: "Ronald F. Guilmette" <rfg@monkeys.com> Cc: Kevin Day <toasty@dragondata.com>, hackers@FreeBSD.ORG Subject: Re: Practical limit for number of TCP connections? Message-ID: <385CEE25.5239137E@newsguy.com> References: <43033.945551665@monkeys.com>
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"Ronald F. Guilmette" wrote: > > As I say, my understanding is that FreeBSD still doesn't have real and/or > complete thread support in the kernel. So if you have a multi-threaded > application and one thread blocks (e.g. on I/O) then the whole thing is > blocked. Ouch! That's just not true. FreeBSD has userland threads. This is faster than kernel threads, but has two disadvantages. First, it doesn't make use of SMP. Second, they all compete together as a single process for CPU time. It seems some programmers prefer to use threads to increase their process' CPU time than lowering the process' priority. OTOH, all releases so far of FreeBSD *do* have incomplete thread support. Some very important functions were missing, but it seems this is (mostly?) solved. Also, the way threads dealt with signals and wakeup's resulted in heavy overhead, but this have been changing, and it's probably ok now. Not to dismiss FreeBSD's kernel problems, but that thing about blocking is absurdly untrue. -- Daniel C. Sobral (8-DCS) who is as social as a wampas dcs@newsguy.com dcs@freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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