On 08/31/2017 07:37 AM, Michael Ellerman wrote: > Stewart Smith <stew...@linux.vnet.ibm.com> writes: > >> Michael Ellerman <m...@ellerman.id.au> writes: >>> OK. So maybe when the petitboot kernel moves up to 4.14 they may want to >>> flip it back to being a module. >> >> Yeah. We tend to keep all RAID adapters as modules because they almost >> all uniquely try to undo all boot time optimization done by anybody, >> anywhere, ever. > > Yes I know what you mean. I am thinking of one In ParticulaR.
Ouch. In all fairness over the life of ipr I've done a couple things to improve initialization time. 1. On a PowerVM machine, the ipr boot device should not get reset between the FCODE driver and the Linux driver, so init is extremely fast. If its a non-boot device, then you'll have to wait for the firmware to initialize on those adapters. 2. On a bare metal machine, if you set ipr.fast_reboot=1 on the skiboot kernel, then we should also avoid resetting the ipr adapter, so ipr init on the kernel being kexec booted from skiboot should be extremely fast. As to improving ipr init time in the skiboot kernel, that becomes more difficult to do safely. The firmware stack still needs to boot, do device discovery, potentially spin up disks, etc, which all takes time. Additionally, we put in changes in the firmware and driver to address complaints largely from Anton about it taking too long for ipr to timeout on bad adapters. If you've got cases where ipr init is taking a long time, I'd be interested to know what scenarios are the most annoying to see if there is any opportunity to improve. -Brian -- Brian King Power Linux I/O IBM Linux Technology Center
