Subject: Re: pktgen: tricks

From: Rick Jones <[email-masked]>
Date: Wed, 23 Sep 2009 18:05:43 -0700

Stephen Hemminger wrote:
> On Tue, 22 Sep 2009 22:49:02 -0700
> Stephen Hemminger <[email-masked]> wrote:
> 
> 
>>I thought others want to know how to get maximum speed of pktgen.
>>
>>1. Run nothing else (even X11), just a command line
>>2. Make sure ethernet flow control is disabled
>>   ethtool -A eth0 autoneg off rx off tx off
>>3. Make sure clocksource is TSC.  On my old SMP Opteron's
>>   needed to get patch since in 2.6.30 or later, the clock guru's
>>   decided to remove it on all non Intel machines.  Look for patch
>>   than enables "tsc=reliable"
>>4. Compile Ethernet drivers in, the overhead of the indirect
>>   function call required for modules (or cache footprint),
>>   slows things down.
>>5. Increase transmit ring size to 1000
>>   ethtool -G eth0 tx 1000
>>
>>Result: OK: 70408581(c70405979+d2602) nsec, 100000000 (60byte,0frags)
>>  1420281pps 681Mb/sec (681734880bps) errors: 0
> 
> 
> Other kernel config help:
>   - turn off lock dependency checker, kmecheck, page alloc debug
>     basically anything that slows stuff down
>   - turn off content group scheduler

I and thought netperf was getting away from real-world?-)

rick jones