[Skiboot] [PATCH 2/2] pci: Make fast reboot creset PHBs in parallel

[Stewart Smith]

Michael Neuling <mikey at neuling.org> writes:
> In this patch, we added a creset to the fast reboot path:
>
>   commit a1eba9d29d17ff44fca1293b071023a9fbf4b938
>   Author: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
>   fast-reboot: creset PHBs on fast reboot
>
> Unfortunately, this does the creset in serial rather than in
> parallel.
>
> This patch changes the creset on fast reboot to operate in
> parallel. It simplifies the code by abstracting pci_init_slots() so
> that it can be used on boot and fast reboot to perform all the PCI
> retraining.
>
> This improves fast reboot PCI training on a dual chip P9 from ~12
> seconds down to ~2 seconds. Similar improvements for P8 are achieved
> as well.
>
> This means the time to download the BOOTKERNEL is the bottleneck for
> fast reboot.
>
> Signed-off-by: Michael Neuling <mikey at neuling.org>
> ---
>  core/pci.c | 51 +++++++++++++++++++++------------------------------
>  1 file changed, 21 insertions(+), 30 deletions(-)

Cheers, fast reboot being even faster is always a bonus!

Series merged to master as of fe6d86b92a0054f7f063cd957091889f4ccd853a

-- 
Stewart Smith
OPAL Architect, IBM.