Re: [PATCH v6 00/11] Parallel CPU bringup for x86_64

[David Woodhouse]

On Sun, 2023-02-05 at 13:17 -0600, Russ Anderson wrote:
> 
> Gave the v6 patchset a try on a system with 1920 logocal cpus
> (sixteen 60 core Sapphire Rapids sockets with Hyperthreadding
> enabled).
> 
> Without the patchset it took 71 seconds to start all the cpus.
> With the v6 patchset it took 14 seconds to start all the cpus,
> a reduction of 57 seconds.  That is impressive.
> 
> Full boot, to root login prompt, without patches takes 223 seconds.
> This patchset reduces the full boot time by 57 seconds, a 25%
> reduction.

Nice; thanks for testing.

Is that with just the "part1" patch series which has been posted, or
also with the 'parallel part 2' still taking shape in the tree at
https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/parallel-6.2-rc6

I believe Usama said the second phase of parallelism didn't really help
much in terms of overall timing? Confirming that *without* all the
debug prints would be interesting. And we can look for what still
*could* be made parallel.

Attachment: smime.p7s
Description: S/MIME cryptographic signature