Hi,
Please follow some steps mentioned below , these steps might include
TCP tuning also, but it doesnot matter because u r sending UDP Traffic
only.
The Steps
Make sure that you have root privleges.
Type: sysctl -p | grep mem
This will display your current buffer settings. Save These! You may
want to roll-back these changes
Type: sysctl -w net.core.rmem_max=8388608
This sets the max OS receive buffer size for all types of connections.
Type: sysctl -w net.core.wmem_max=8388608
This sets the max OS send buffer size for all types of connections.
Type: sysctl -w net.core.rmem_default=65536
This sets the default OS receive buffer size for all types of
connections.
Type: sysctl -w net.core.wmem_default=65536
This sets the default OS send buffer size for all types of connections.
Type: sysctl -w net.ipv4.tcp_mem='8388608 8388608 8388608'
TCP Autotuning setting. "The tcp_mem variable defines how the TCP stack
should behave when it comes to memory usage. ... The first value
specified in the tcp_mem variable tells the kernel the low threshold.
Below this point, the TCP stack do not bother at all about putting any
pressure on the memory usage by different TCP sockets. ... The second
value tells the kernel at which point to start pressuring memory usage
down. ... The final value tells the kernel how many memory pages it may
use maximally. If this value is reached, TCP streams and packets start
getting dropped until we reach a lower memory usage again. This value
includes all TCP sockets currently in use."
Type: sysctl -w net.ipv4.tcp_rmem='4096 87380 8388608'
TCP Autotuning setting. "The first value tells the kernel the minimum
receive buffer for each TCP connection, and this buffer is always
allocated to a TCP socket, even under high pressure on the system. ...
The second value specified tells the kernel the default receive buffer
allocated for each TCP socket. This value overrides the
/proc/sys/net/core/rmem_default value used by other protocols. ... The
third and last value specified in this variable specifies the maximum
receive buffer that can be allocated for a TCP socket."
Type: sysctl -w net.ipv4.tcp_wmem='4096 65536 8388608'
TCP Autotuning setting. "This variable takes 3 different values which
holds information on how much TCP sendbuffer memory space each TCP
socket has to use. Every TCP socket has this much buffer space to use
before the buffer is filled up. Each of the three values are used under
different conditions. ... The first value in this variable tells the
minimum TCP send buffer space available for a single TCP socket. ...
The second value in the variable tells us the default buffer space
allowed for a single TCP socket to use. ... The third value tells the
kernel the maximum TCP send buffer space."
Type:sysctl -w net.ipv4.route.flush=1
This will enusre that immediatly subsequent connections use these
values.
please let me know if u have any more questions.
Thanks,
Sunil
http://geocities.com/sunil3112000
(E-Mail Removed) wrote:
> Hello,
>
> I am trying to send a large number of UDP packets through one nick.
> Each packet is smaller than 200 byes.
> I am working with a gigabit ethernet on a LAN.
>
> I am testing it with x86_64 intel processor and with Intel e1000 nic.
> The nic works with coalescent interrupts, aka NAPI.
> I tried to send about 50,000 packets and I see that there is a loss
> of about 5%-10%.
> I want to be able to send more than 50,000 packets,
> to tune the machine and be able to squeeze resources and send as much
> as possible.
> I had looked for linux networking tunables which will allow me
> to be able to send more packets.
> I tried to set /proc/sys/net/core/netdev_max_backlog to 5000
> and more, and txqueuelen of the nic (you can see it in
> ifconfig) to 5000 or more. Still I have these results
> of 5%-10% loss when sending 50000 packets.
>
> Are there more tunables/techniques which I consider ?
>
> Any help will be appreciated.
>
> Regards,
> Ian
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