is RTL8139 THAT bad?

Sergey Babkin babkin at verizon.net
Mon Jun 22 00:22:52 UTC 2009


Wojciech Puchar wrote:
> 
> > Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl> writes:
> >> Why it's THAT bad?
> >
> > http://svn.freebsd.org/base/head/sys/pci/if_rl.c
> >
> > Scroll down past the copyright, license and attribution.  Read the
> > 38-line comment that explains just how crappy this chip really is.
> 
> Well - really "low end".
> 
> But - this computer can do memcpy at 80MB/s, so at 3.5MB/s it should be 5%
> CPU for memcpy, and one interrupt per one packet (2500 packets/s).
> 
> Is something more that make it consume >50% CPU?

Accessing the on-card memory through PCI is guaranteed to be
slower than the main memory, and depending on the particular
card it may be much slower.

-SB


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