Messages in this thread | | | Date | Tue, 23 Nov 2004 09:50:36 +1100 | From | Lincoln Dale <> | Subject | Re: Linux 2.6.9 pktgen module causes INIT process respawning and sickness |
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Jeff,
At 04:06 AM 23/11/2004, Jeff V. Merkey wrote: >I've studied these types of problems for years, and I think it's possible >even for Linux.
so you have the source code --if its such a big deal for you, how about you contribute the work to make this possible ?
the fact is, large-packet-per-second generation fits into two categories: (a) script kiddies / haxors who are interested in building DoS tools (b) folks that spend too much time benchmarking.
for the (b) case, typically the PPS-generation is only part of it. getting meaningful statistics on reordering (if any) as well as accurate latency and ideally real-world traffic flows is important. there are specialized tools out there to do this: Spirent, Ixia, Agilent et al make them.
>[..] >I see no other way for OS to sustain high packet loading about 500,000 >packets per second on Linux >or even come close to dealing with small packets or full 10 gigabite >ethernet without such a model.
10GbE NICs are an entirely different beast from 1GbE. as you pointed out, with real-world packet sizes today, one can sustain wire-rate 1GbE today (same holds true for 2Gbps Fibre Channel also).
i wouldn't call pushing minimum-packet-size @ 1GbE (which is 46 payload, 72 bytes on the wire btw) "real world". and its 1.488M packets/second.
>The bus speeds are actually fine for dealing with this on current hardware.
its fine when you have meaningful interrupt coalescing going on & large packets to DMA. it fails when you have inefficient DMA (small) with the overhead of setting up & tearing down the DMA and associated arbitration overhead.
cheers,
lincoln.
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