The overhead for the OpenBMC firmware images using the a custom U-Boot
is around 2 seconds, which is fine, but with a U-Boot from mainline,
it takes an extra 50 seconds or so to reach Linux. A quick survey on
the number of reads performed on the flash memory region gives the
following figures :
OpenBMC U-Boot 922478 (~ 3.5 MBytes)
Mainline U-Boot 20569977 (~ 80 MBytes)
QEMU must be trashing the TCG TBs and reloading text very often. Some
addresses are read more than 250.000 times. Until we find a solution
to improve boot time, execution from MMIO is not activated by default.
Setting this option also breaks migration compatibility.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200114103433.30534-5-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
1a15311a12