On Wed, 23 Oct 2002, bert hubert wrote:
> On Wed, Oct 23, 2002 at 03:42:48PM +0200, Roy Sigurd Karlsbakk wrote:
> > > The e1000 can very well do hardware checksumming on transmit.
> > >
> > > The missing piece of the puzzle is that his application is not
> > > using sendfile(), without which no transmit checksum offload
> > > can take place.
> >
> > As far as I've understood, sendfile() won't do much good with large files. Is
> > this right?
>
> I still refuse to believe that a 1.8GHz Pentium4 can only checksum
> 250megabits/second. MD Raid5 does better and they probably don't use a
> checksum as braindead as that used by TCP.
>
> If the checksumming is not the problem, the copying is, which would be a
> weakness of your hardware. The function profiled does both the copying and
> the checksumming.
>
> But 250megabits/second also seems low.
>
> Dave?
>
Ordinary DUAL Pentium 400 MHz machine does this...
Calculating CPU speed...done
Testing checksum speed...done
Testing RAM copy...done
Testing I/O port speed...done
CPU Clock = 400 MHz
checksum speed = 685 Mb/s
RAM copy = 1549 Mb/s
I/O port speed = 654 kb/s
This is 685 megaBYTES per second.
checksum speed = 685 Mb/s
Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Bush : The Fourth Reich of America
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:41 EST