Re: Kernel 2.4.6 & 2.4.7 networking performance: seeing serious delays

Ron Flory (ron.flory@adtran.com)
Thu, 09 Aug 2001 13:59:00 -0500


Shirley Ma wrote:
>
> Hi, Ron,
>
> I am interested the problem you posted. I tried to reproduce
> this problem on my machine and failed. Would you please point your
> programs to me, so I can reproduce this problem and do more
> investigation? If not, please let me know whether it is reproducible,
> and please collect both client/server ethereal log.

OK, will follow-on in a private email (to minimize lkml traffic)

I can easily reproduce the problem by performing a socket 'write' as
two separate operations:

write(sock, buf1..)
write(sock, buf2..)

If on the other hand I combine the buffers then issue a single
'write':

write(sock, both_bufs...)

the problem magically disappears (because the inter-block handshaking
requirements change, which is where I think the problem actually lies).

Since the problem is also present using the loopback device, both
client/server sides would be present in a Ethereal long of LO.

I would imagine anybody running a large Linux ftp/http server would be
interested in this...

ron
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