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Re: Is sendfile all that sexy?

To: hadi@xxxxxxxxxx (jamal)
Subject: Re: Is sendfile all that sexy?
From: kuznet@xxxxxxxxxxxxx
Date: Sun, 14 Jan 2001 23:29:24 +0300 (MSK)
Cc: netdev@xxxxxxxxxxx
In-reply-to: <Pine.GSO.4.30.0101141446450.12354-100000@xxxxxxxxxxxxxxxx> from "jamal" at Jan 14, 1 03:07:08 pm
Sender: owner-netdev@xxxxxxxxxxx
Hello!

> 256M.

8Mb file should be enough.

At least, I do see real difference between the first and subsequent
runs with 32MB file and 512M machine. You do not and this is funny.


> I think the L2 cache on these machine is 512KB. So something slightly
> larger (600KB)?

 >2*L2 cache. Otherwise it is not invalidated.


> How Large? 170M currently.

Seems, your first experiment was 16M. It was reasonable.
I have no idea why you did not see differences between runs,
it is simply impossible.


> tput: 68MB/sec (compare to 86MB/sec)

Sorry? But what did you measure earlier? 8)


> So i would say that CPU utilization has improved incredibly, but
> throughput has gone down.

I have no idea, throughput grows here on similar hardware.
And by the way, numbers are pretty similar, but inverted. 8)

Alexey

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