Re: Very poor TCP/SACK performance

Savochkin Andrey Vladimirovich (saw@msu.ru)
Tue, 8 Sep 1998 15:57:57 +0400


On Tue, Sep 08, 1998 at 12:42:13AM -0700, David S. Miller wrote:
> 23:32:32.941103 207.75.226.50.20 > 207.75.231.233.1075: P 75981:76505(524) ack 0 win 32488 <nop,nop,timestamp 3926083 730030> (DF) [tos 0x8]
> 23:32:32.941103 207.75.226.50.20 > 207.75.231.233.1075: P 64977:65501(524) ack 0 win 32488 <nop,nop,timestamp 3926084 730030> (DF) [tos 0x8]

[snip]

> One thing you can try to alleviate this situation is to up the default
> window sizes a bit using the knobs in:
>
> /proc/sys/net/core/{r,w}mem_{max,default}

Well, I can confirm that the default rmem setting is insufficient
for a stream of small packets (524 bytes here).

David, it's not the first report about "strange" throughput for streams
of small packets. What do you think about changing default window size
or default receive buffer size?

Best wishes
Andrey V.
Savochkin

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