On Wednesday, June 09, 1999 1:11 PM, Joe [SMTP:[EMAIL PROTECTED]] wrote:
> Netscape uses threads which in turn use "buzz" locks, (or short
> spin locks) for mem locking. (OK)
Netscape uses user-mode threads, if I remember correclty, although perhaps
they're switching to real threads. That would mean one process, and some
really unpleasant (and hang-prone) code switching contexts. (SIGALRM,
etc.).
The whole question of whether "native" (i.e. _not_ usermode) threads should
be supported directly by the kernel or via processes is rather contentious.
It bites both ways -- if one is moving from Linux to NT, the first thought
is: "NT stinks, the process creation overhead is terrible." The answer is:
"Well, you should be using threads (or fibers)." Coming from NT to Linux,
the first two thoughts are: "Linux stinks, it has only user-mode threads"
or "Linux stinks, if you want to use preemptive threads, you end up
creating one process per thread, plus a manager process, and that must be
slow!". The answer is: "Yes, it does have native mode threads, and the
process overhead for Linux is less than that for NT."
So it's really a deep architectural debate, with pressure on Linux to get
special handling for processes that are really threads (e.g. keep all
"process threads" on the same processor, etc.) [re: linux-kernel a few
weeks ago] and with pressure on NT to get "lighter processes" (threads,
fibers, etc.).
IMHO, in the future there will be convergence, with NT and Linux coming
towards each other on some of these issues.
Eugene Kuznetsov
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