Re: New != Faster

On Tue, Jun 05, 2007 at 11:06:52PM +0100, Chris wrote:
On 04/06/07, Kris Kennaway <kris@xxxxxxxxxxxxxx> wrote:
On Mon, Jun 04, 2007 at 08:54:50PM +0100, Chris wrote:
On 04/06/07, Colin Percival <cperciva@xxxxxxxxxxx> wrote:
Tim Daneliuk wrote:
Old 2 PIII @600Mhz 768K 26M/sec 4.11-stable/SMP
50-60 min
New Pent D (2 core)@3.2GHz 2G 50M/sec 6.2-stable/SMP
40-50 min
Fast 2 Xeon @3GHz 3G 130M/sec 4.11-stable/SMP
8 min

Is the difference in speed
attributable to 4.11 being faster than 6.2?

Close. The difference in speed is due to the compiler in 4.11 being
faster than the compiler in 6.2. FreeBSD uses the gcc compiler, and
between FreeBSD 4.11 and FreeBSD 6.2 that has been upgraded from 2.9
to 3.4. The general trend each time gcc is upgraded is that it takes
2x longer to compile code, but produces code which is 5% faster (as a
result of "working harder" to find optimizations).

FreeBSD 6.2 is faster than FreeBSD 4.11 for almost everything except
compiling itself. :-)

Colin Percival

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What about all the following observations?

slower disk performance especially under QUOTA.

s/especially//, unless you have further evidence I don't know about.

both of these have been confirmed numerous times by different people
so sweeping them under the carpet and saying they simply not true
would be wrong.

My detailed measurements of disk performance and those of others I am
aware of contradicts your claim: 6.x equals or outperforms 4.x on disk
I/O (depends on driver) and filesystem I/O. The only true part of it
is the "under QUOTA" part, which as you know from past discussions, is
still under Giant in 6.x. As you also know, there is a patch to
address this which is awaiting user testing. Have you tested it yet?

Kris

Having some hardware coming this week when thats all setup I will have
a box available for testing patches.

Glad to hear it. It is kind of irritating that you keep loudly
complaining about how terrible QUOTA performance is but have so far
avoided participating in the solution to that problem.

So, just to confirm, you do not in fact have evidence of poor disk
performance apart from this?

Kris
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