Date: Fri, 30 Oct 1998 23:00:01 -0800 (PST) From: Peter Wemm <peter@netplex.com.au> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/8500: FreeBSD 3.0 thread scheduler is broken Message-ID: <199810310700.XAA21810@freefall.freebsd.org>
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The following reply was made to PR kern/8500; it has been noted by GNATS. From: Peter Wemm <peter@netplex.com.au> To: info@highwind.com Cc: freebsd-gnats-submit@FreeBSD.ORG Subject: Re: kern/8500: FreeBSD 3.0 thread scheduler is broken Date: Sat, 31 Oct 1998 14:50:24 +0800 info@highwind.com wrote: > >Number: 8500 > >Category: kern > >Synopsis: FreeBSD 3.0 thread scheduler is broken > > >Description: > When an application has threads that are I/O intensive, that thread > unfairly steals cycles from all other threads. This makes writing > an MT program that does any real amount of I/O impossible. Yes, open(), read(), write(), etc block the entire process. The libc_r thread engine only works for things that can be select()ed apon, and read/ write cannot (yet). The only alternatives are to use the aio/lio syscalls (which work), or rfork(). libc_r could probably be modified to use rfork() to have the read/write/open/close/etc done in parallel. Cheers, -Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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