perfSONAR User Q&A and Other Discussion

[Kathy Benninger <>]

Hi Pete,

The typical recommendation is to let the system set the values for 
net.ipv4.tcp_mem at boot.

net.ipv4.tcp_mem values are in units of memory pages (not bytes as are the 
rmem and wmem settings) and are calculated based on the amount of system memory.

Kathy


On 12/7/2017 3:05 PM, pete wrote:
> Hi, I've been tasked with setting up a speedtest html5 service to run on our 
> perfsonar servers to replace NDT testing.  This would run through apache via 
> php.  Their instructions ask the user to update several tcp related kernel 
> tunings.
>
> Does anyone have any experience or insight into how this might effect our 
> perfsonar regular tests?
>
>
> Here are our current standard tunings on our perfsonar mahcines:
>
>    net.core.wmem_max = 124928
>    net.ipv4.tcp_rmem = 4096    87380    4194304
>    net.ipv4.tcp_wmem = 4096    16384    4194304
>    net.ipv4.tcp_mem = 3079392    4105856    6158784
>    net.core.netdev_max_backlog = 1000
>    net.ipv4.ip_local_port_range = 32768    60999
>    net.ipv4.tcp_congestion_control = cubic
>
> Here are the CHANGES requested:
>
>    net.core.wmem_max = 16777216
>    net.ipv4.tcp_rmem = 4096 87380 16777216
>    net.ipv4.tcp_wmem = 2096 65535 16777216
>    net.ipv4.tcp_mem = 98304 131072 196608
>    net.core.netdev_max_backlog = 250000
>    net.ipv4.ip_local_port_range = 1025 61000
>    net.ipv4.tcp_congestion_control=htcp
>
>
> The instructions are posted here for reference: 
> https://github.com/adolfintel/speedtest/issues/50
>
> Thoughts?
>
> Thanks,