[gPXE-devel] gPXE performance under virtualization

[Geoff Lywood]

Please be very careful about using direct VGA and PC keyboard in the default build. On many machines, int 10h also goes to a serial port (or can be configured to do so). Many people rely on serial as a means of remotely monitoring servers, and your optimizations would break their workflow.

It might be better to optimize is_key() so that it checks bytes 0040:001a and 0040:001c in the BIOS data area before dropping into real mode. I'm not sure what kind of compatibility problems that would hit, but it might be worth a try.

I'd also like to point out that including serial console support in its current state is a bad idea: if you ever enable the serial console on a machine without a serial port, it will behave as if the backspace key is permanently held down, rendering any user interface useless.

Thanks,
Geoff


> -----Original Message-----
> From: gpxe-devel-bounces at etherboot.org [mailto:gpxe-devel-
> bounces at etherboot.org] On Behalf Of Stefan Hajnoczi
> Sent: Tuesday, July 06, 2010 1:04 PM
> To: gpxe-devel at etherboot.org
> Cc: mcb30 at ipxe.org
> Subject: Re: [gPXE-devel] gPXE performance under virtualization
> 
> The TL;DR version of my email:
> 
> *** more than 40% improvement in download time under KVM ***
> 
> Now we just need the patches to cleanly get this improvement in a default
> build.
> 
> Stefan
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