Re: [Discuss-gnuradio] New implementation for fusb_linux withoutallocs/frees

[Stefan Bruens]

On Tuesday 24 February 2009 16:03:05 Marcus D. Leech wrote:
> Have you tested receive performance, and is it improved?

Hm, if you are going for high bandwidth, you should set the blocksize quite 
high (eg 4096). I am targetting low latency, so I go for the smallest possible 
blocksize (512).

If you are receiving with 32MB/s, the new code saves about 75e6 instructions 
per second at a blocksize of 512, so for 4096 this should be about 9e6. For a 
current generation cpu, this should be about 1% of its throughput, on the 
other hand, the mallocs are most probably very unfriendly to branch prediction 
and cache access, so savings may be higher. If I find some time, I will run 
oprofile to get some numbers ...

Stefan

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