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Date:      Tue, 29 Jun 1999 22:19:22 +0000 (GMT)
From:      Terry Lambert <tlambert@primenet.com>
To:        vanmaren@fast.cs.utah.edu (Kevin Van Maren)
Cc:        tlambert@primenet.com, vanmaren@cs.utah.edu, freebsd-smp@FreeBSD.ORG
Subject:   Re: high-efficiency SMP locks - submission for review
Message-ID:  <199906292219.PAA00305@usr08.primenet.com>
In-Reply-To: <199906292144.PAA27790@fast.cs.utah.edu> from "Kevin Van Maren" at Jun 29, 99 03:44:16 pm

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> I also recall hearing that Solaris was slower on a uniprocessor
> than FreeBSD, partly due to the locking/synchronization in the kernel.

I credit this to their VFS reentrancy model, which I think is
The Wrong Way To Do It.

I think that locking objects instead of locking entrancy to the
small bits of code that modify such objects is probably the
culprit.  When you lock object with fine granularity, you
aren't saying enough about how long you hold the locks.  The
object lock cost is much higher than necessary or desirable, IMO.


> > FreeBSD did worse than Linux, both SMP and UP.
> 
> I didn't see any FreeBSD numbers; I'll have to go look again.

The FreeBSD numbers are from Ziff-Davis via Mike Smith.


> It wasn't that long ago FreeBSD was beating the pants off Linux.
> I guess we've been standing too still for too long.

Time for FreeBSD to wake up...


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.


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