Re: [RFC PATCH v2] tcp: TCP Small Queues

Rick Jones
2012-07-11T18:44:21Z

On 07/11/2012 08:11 AM, Eric Dumazet wrote:
>
> Some bench results about the choice of 128KB being the default value:

What were the starting/baseline figures?

>
> Tests using a single TCP flow.
>
> Tests on 10Gbit links :
>
>
> echo 16384 >/proc/sys/net/ipv4/tcp_limit_output_bytes
> OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.99.2 (192.168.99.2) port 0 AF_INET
> tcpi_rto 201000 tcpi_ato 0 tcpi_pmtu 1500 tcpi_rcv_ssthresh 14600
> tcpi_rtt 1875 tcpi_rttvar 750 tcpi_snd_ssthresh 16 tpci_snd_cwnd 79
> tcpi_reordering 53 tcpi_total_retrans 0
> Local Local Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service
> Send Socket Send Socket Send Time Units CPU CPU CPU CPU Service Service Demand
> Size Size Size (sec) Util Util Util Util Demand Demand Units
> Final Final % Method % Method
> 392360 392360 16384 20.00 1389.53 10^6bits/s 0.52 S 4.30 S 0.737 1.014 usec/KB

By the way, that double reporting of the local socket send size is fixed in:

------------------------------------------------------------------------
r516 | raj | 2012-01-05 15:48:52 -0800 (Thu, 05 Jan 2012) | 1 line

report the rsr_size_end in an omni stream test rather than a copy of the
lss_size_end

of netperf and later. Also, any idea why the local socket send size got
so much larger with 1GbE than 10 GbE at that setting of
tcp_limit_output_bytes?

> Tests on Gbit link :
>
>
> echo 16384 >/proc/sys/net/ipv4/tcp_limit_output_bytes
> OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 172.30.42.18 (172.30.42.18) port 0 AF_INET
> tcpi_rto 201000 tcpi_ato 0 tcpi_pmtu 1500 tcpi_rcv_ssthresh 14600
> tcpi_rtt 1875 tcpi_rttvar 750 tcpi_snd_ssthresh 30 tpci_snd_cwnd 274
> tcpi_reordering 3 tcpi_total_retrans 0
> Local Local Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service
> Send Socket Send Socket Send Time Units CPU CPU CPU CPU Service Service Demand
> Size Size Size (sec) Util Util Util Util Demand Demand Units
> Final Final % Method % Method
> 1264784 1264784 16384 20.01 689.70 10^6bits/s 0.22 S 15.05 S 0.634 7.149 usec/KB

rick jones