Date: Tue, 22 Apr 2003 12:18:10 +0400 (MSD) From: Igor Sysoev <is@rambler-co.ru> To: Daniel Eischen <eischen@pcnet1.pcnet.com> Cc: threads@freebsd.org Subject: Re: libkse -> libpthread Message-ID: <Pine.BSF.4.21.0304221208160.94232-100000@is> In-Reply-To: <Pine.GSO.4.10.10304211431080.14573-100000@pcnet1.pcnet.com>
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On Mon, 21 Apr 2003, Daniel Eischen wrote: > On Mon, 21 Apr 2003, Terry Lambert wrote: > > > Jeff Roberson wrote: > > > On Mon, 21 Apr 2003, Daniel Eischen wrote: > > > > Since libkse seems to be generally useful, anyone mind if I > > > > go back to installing it as libpthread? > > > > > > There is some question over whether kse or thr will be the default > > > threading implementation for 5.1. I think this should be discussed before > > > we decide on what lib uses libpthread. > > > > Isn't libthr really just libkse with N = M? > > Yes, I wasn't going to bring that up, though. > > > These should behave exactly the same, right? It should even be > > possible to drop the UTS out of the picture for everything but > > signal handling, I think (i.e. it would never get upcalled) in > > the 1:1 case, if this were done? > > Libpthread can be made to behave the same as libthr just > by forcing every thread to be scope system. Currently, > the implementation for scope system threads does have > a small amount of overhead in that they still get upcalls > after the thread blocks in the kernel (in this case > the KSE just reenters the kernel with kse_release() > and waits for the thread to become unblocked). These > KSEs also require a small stack separate from the > thread's stack. The code is in place (in the UTS) to > not require a separate stack and not get any upcalls > for these threads, but we just need a bit more > kernel work to optimize this overhead away. But why is not it implemented via setting kse_mailbox.km_curthread to NULL ? As I understand it's way to disable upcalls when UTS is preempted by the kernel (the time slice ended, the page in operation, etc.) i.e. UTS should always run as 1:1 thread. Had it been changed ? How is UTS protected now ? Igor Sysoev http://sysoev.ru/en/
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