[syslinux] http slow transfer

[H. Peter Anvin]

On 11/29/2014 09:20 AM, Ferenc Wagner wrote:
> חץ בן חמו <hetz at benhamo.org> writes:
> 
>> I've converted a CentOS Live ISO to PXE, and I'm using lpxelinux.0 to boot
>> it.
>> Without any HTTP method in the lines, the files are transferring without
>> any problems, but as soon as I use http, all the transferring action is
>> super slow - 5-8 times slower compared to stanard TFTP/UDP transfer (with
>> the same lpxelinux.0)
> 
> I don't know much about lpxelinux technology, so I can't help you, but
> usually the first step is taking a packet capture, see
> http://www.syslinux.org/wiki/index.php/Debugging.  Looking into the dump
> may provide clues.  The other thing is trying pxelinux.0 atop iPXE with
> HTTP support (in the simplest case booted from some local device).
> 

My guess is that the UNDI stack in the BIOS is dropping packets.  A
packet trace would probably reveal that in the form of excessive
retransmits.

	-hpa