[CentOS] Problems with motherboard support? INTEL DP43BF

Tue Dec 28 22:28:24 UTC 2010
Fernando Gleiser <fergleiser at yahoo.com>


----- Original Message ----
> From: John R Pierce <pierce at hogranch.com>
> To: centos at centos.org
> Sent: Tue, December 28, 2010 2:59:09 AM
> Subject: Re: [CentOS] Problems with motherboard support? INTEL DP43BF
> 
> On 12/27/10 9:09 PM, robert mena wrote:
> > Regular realtek fast  ethernet.
> 
> IMNSHO, realtek are pretty close to junk grade NICs.    they have far too 
> many variations with far too many weird bugs when used for  any more than 
> single user desktop kind of systems.
> 

rl nics are toy nics. I wouldn't use them on production servers unless I have no 
choice

For some reasons, see this, textually from FreeBSD's 5.4 if_rl.c:

/*
 * The RealTek 8139 PCI NIC redefines the meaning of 'low end.' This is
 * probably the worst PCI ethernet controller ever made, with the possible
 * exception of the FEAST chip made by SMC. The 8139 supports bus-master
 * DMA, but it has a terrible interface that nullifies any performance
 * gains that bus-master DMA usually offers.
 *
 * For transmission, the chip offers a series of four TX descriptor
 * registers. Each transmit frame must be in a contiguous buffer, aligned
 * on a longword (32-bit) boundary. This means we almost always have to
 * do mbuf copies in order to transmit a frame, except in the unlikely
 * case where a) the packet fits into a single mbuf, and b) the packet
 * is 32-bit aligned within the mbuf's data area. The presence of only
 * four descriptor registers means that we can never have more than four
 * packets queued for transmission at any one time.
 *
 * Reception is not much better. The driver has to allocate a single large
 * buffer area (up to 64K in size) into which the chip will DMA received
 * frames. Because we don't know where within this region received packets
 * will begin or end, we have no choice but to copy data from the buffer
 * area into mbufs in order to pass the packets up to the higher protocol
 * levels.
 *


sadly, things hadn't improved since then


Fer