Re: kern/40419 (processor sets broken on 5.99.6)

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

The following reply was made to PR kern/40419; it has been noted by GNATS.

From: Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>
To: Andrew Doran <ad%netbsd.org@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%netbsd.org@localhost, 
gnats-admin%netbsd.org@localhost
Subject: Re: kern/40419 (processor sets broken on 5.99.6)
Date: Wed, 21 Jan 2009 00:01:49 +0000

 Andrew Doran <ad%netbsd.org@localhost> wrote:
 > > We can do yield() in sys__pset_bind(). Do you think it is worth?
 > 
 > I was thinking of a function that scans all threads, with cpu_lock held, and
 > checks to see if their l_cpu is allowed by their affinity mask, processor
 > set or LP_BOUND flag. If not, change l_cpu (or migrate if online), then do a
 > broadcast xcall to nullop() if there have been migrations.
 
 After some thinking, I do not think it is worth. Theoretically, xc_broadcast
 might still not ensure that all LWPs have migrated, eg. in a case when there
 are many migrating LWPs in the same run-queue.
 
 After last fixes, I think migration should be very fast (~immediate) anyway,
 just re-scheduling overhead.
 
 -- 
 Best regards,
 Mindaugas