DragonFly commits List (threaded) for 2007-08
DragonFly BSD
DragonFly commits List (threaded) for 2007-08
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Re: cvs commit: src/sys/ddb db_ps.c src/sys/kern init_main.c kern_exit.c kern_fork.c kern_resource.c kern_sig.c sys_generic.c src/sys/platform/pc32/i386 pmap.c src/sys/platform/vkernel/platform pmap.c src/sys/sys proc.h tree.h src/sys/vm vm_vmspace.c


From: "Simon 'corecode' Schubert" <corecode@xxxxxxxxxxxx>
Date: Wed, 15 Aug 2007 09:47:59 +0200

Matthew Dillon wrote:
  Log:
  Convert the lwp list into a red-black tree.  This greatly reduces the
  overhead of looking up LWPs for numerous operations including select and
  removes the hokey fork code that tried to avoid doing a list traversal.

I think this an absolutely false move. *Only* for select this is O(N), and select was O(N) before, so we didn't lose anything. The RB-tree just makes everything more complicated. The right thing to fix is the old, sucky select code.


I think such changes should be discussed beforehand. In this case I think the change should be backed out unless there is proof that it fixes a performance issue (other than the broken select).

cheers
 simon

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