[syslinux] Very slow download with pxelinux > 4.07 on specific hardware

[Eric PEYREMORTE]

Notice the same thing happens with optiplex 790 (core i5 sandy bridge).

With 790 too everything is ok with pxelinx 4.0.7.

I'll post a wireshark later.

Le 25/02/2014 17:06, H. Peter Anvin a écrit :
> On 02/25/2014 07:45 AM, H. Peter Anvin wrote:
>> On 02/25/2014 07:07 AM, Eric PEYREMORTE wrote:
>>> I did some additional tests :
>>>
>>> On a dell optiplex 380, i disabled internal nic, added a 3com 905c tx
>>> external pci nic : very slow too.
>>> On a dell 740(which is always fast), i put the 3com to be sure : very fast.
>>>
>>> So it seems it is not related to the nic itself. To be sure it wasn't
>>> just one failing computer i tested several 380.
>>>
>>> I tried disabling several features in bios, like Execute Disable,
>>> multicore support, speedstep... Nothing helped.
>>>
>>> I thought at the beginning it was an efi problem (althought i use it in
>>> bios mode), but on optiplex 7010 which is efi based too, i don't have
>>> the problem...
>>>
>>> I used 6.03pre2 for this test.
>>>
>>> As i said previously no problem before version 5.00.
>>>
>> OK, this is extremely surprising.  Normally the NIC card BIOS is what
>> matters for PXE performance, but it sounds like in your case there is
>> something going on in the main BIOS that is causing problems.
>>
> What I'm at a loss for is *how* that would happen.  The biggest
> difference that I can think of is in the layout of the memory, but that
> shouldn't cause that kind of thing.
>
> Sending the wireshark trace might be useful, it certainly can't hurt.
>
> If there is a lost interrupt somehow that might explain the problem, but
> that shouldn't be related to Syslinux 4 vs 5/6 in any way...
>
> 	-hpa
>
>
>


-- 
Eric PEYREMORTE
Technicien Informatique - CRI
http://www.iut-valence.fr
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