Messages in this thread | | | Date | Mon, 6 Feb 2023 12:18:00 +0000 | Subject | Re: [External] Re: [PATCH v6 00/11] Parallel CPU bringup for x86_64 | From | Usama Arif <> |
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On 06/02/2023 08:28, David Woodhouse wrote: > 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.
I think it would be interesting to get the numbers for such a big machine for 3 cases: part1, part1+reuse timer calibration and part1+part2.
Russ mentioned testing v6, so I guess the above numbers are for part1+reuse timer calibration.
For my machine the smpboot times were:
No patches: 700ms part 1:100ms part1+reuse timer calibration: 30ms part1+part2: 30ms
Thanks, Usama
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