[ipxe-devel] [PATCH] [EFI] Dynamically determine EFI tick count

Michael Brown mcb30 at ipxe.org
Mon Jun 13 08:53:38 UTC 2016

On 13/06/16 07:03, Leendert van Doorn wrote:
> UEFI timer ticks vary per implementation. Fortunately there is an architectural
> timer protocol through which we can query the tick period. This patch removes
> the hard coded tick setting for EFI and replaces it with code that sets it
> dynamically.

We do not want to run the timer callback at the maximum possible rate, 
since that is incredibly wasteful of CPU.

The current code uses bs->SetTimer() to start a low-overhead timer 
callback running at 20Hz, which is all we need to handle retransmission 
timeouts.  (The equivalent timer under BIOS runs at 18.2Hz.)


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