[syslinux] Syslinux 4.04 gpxelinux.0 http performance problem with VMware VMs

[Pasi Kärkkäinen]

On Mon, May 07, 2012 at 09:53:35PM -0400, Gene Cumm wrote:
> On Mon, May 7, 2012 at 4:40 PM, Pasi Kärkkäinen <pasik at iki.fi> wrote:
> > Hello,
> >
> > In my testing environment I have two VMs on ESXi 5.0.
> >
> > VM A = dhcp/tftp/PXE/http server, running CentOS 6.2. Syslinux 4.04 with the included gpxelinux.0.
> > VM B = PXE boot client.
> 
> > Any ideas what's causing the bad performance and those continuous retransmits?
> > Anything I should try to debug this?
> >
> > On baremetal with Intel NICs I've seen much better gpxelinux.0 download speeds over http.
> 
> Syslinux 4.04 is obsolete and probably not worth debugging.  4.05 is
> current and 4.10-pre20 is a beta with lwIP, a lightweight IP stack,
> eliminating the need for gPXE if you only want HTTP downloads.  I've
> already been testing 4.10-pre* in VMware VMs with success after my
> patch.  I've seen a solid 45-70 MB/s after that patch on VMware VMs.
> 

That sounds really nice! I'll have to try the new stuff.


> If I recall correctly, the issue you notice is actually how that
> version of gPXE talks with the VMware VM PXE stack.
>

Yeah it feels like bad interaction between gPXE <-> VMware VM PXE.

Anyway, thanks for the reply, I'll try the new stuff 
and let you know how it goes!


-- Pasi