Date: Sun, 8 Mar 1998 01:16:36 -0500 (EST) From: "John S. Dyson" <dyson@FreeBSD.ORG> To: nate@mt.sri.com (Nate Williams) Cc: jb@cimlogic.com.au, nate@mt.sri.com, cvs-committers@FreeBSD.ORG Subject: Re: cvs commit: src/lib/libc_r/uthread pthread_private.h uthread_yield.c Message-ID: <199803080616.BAA02003@dyson.iquest.net> In-Reply-To: <199803080536.WAA06540@mt.sri.com> from Nate Williams at "Mar 7, 98 10:36:31 pm"
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Nate Williams said: > > > > that it will all just come out in the wash. Kernel threads aren't > > > > light weight, though. > > > > > > If kernel threads aren't light-weight, then what differentiates them > > > from processes? > > > > Shared address space. > > You can do that easily enough know with mmap'd files, and or SYSV shmem. > It would seem to me that heavy-weight threads don't buy you anything > that you can't already do know. Heck, someone could write up a library > that does that already, making the details hidden like the user-land > pthreads library. > (Condensed version of what I sent to Nate and John privately.) The threads that we are supporting is not reasonably possible with what you describe. The heavy-weight threads do buy us heavy-weight threads instead of multiple processes and a broken api or user process threads and a broken api. With what we are implementing, we have something better (more efficient) than multiple processes, even if it *could* be implemented with multiple full processes (without api hacks.) However, it isn't as efficient as a lightweight thread scheme (but not all that bad.) I can picture EXACTLY what we need to do, but simply do not have the waking hours. There are significant ways that our kernel threads are more efficient than multiple processes, and we would not be doing it unless it was much better than multiple processes. We are taking baby steps, instead of not taking any steps. It would be nice if criticism would be accompanied with help or diagnosis, and not include dismissal. -- John | Never try to teach a pig to sing, dyson@freebsd.org | it just makes you look stupid, jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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