From: Nick Bowler <nbowler@draconx.ca>
To: sparclinux@vger.kernel.org
Cc: Atish Patra <atish.patra@oracle.com>
Subject: PROBLEM: Only one CPU active on Ultra 60 since ~4.8 (regression)
Date: Tue, 12 Jul 2022 01:38:46 -0400 [thread overview]
Message-ID: <CADyTPEwt=ZNams+1bpMB1F9w_vUdPsGCt92DBQxxq_VtaLoTdw@mail.gmail.com> (raw)
Hi,
When using newer kernels on my Ultra 60 with dual 450MHz UltraSPARC-II
CPUs, I noticed that only CPU 0 comes up, while older kernels (including
4.7) are working fine with both CPUs.
I bisected the failure to this commit:
9b2f753ec23710aa32c0d837d2499db92fe9115b is the first bad commit
commit 9b2f753ec23710aa32c0d837d2499db92fe9115b
Author: Atish Patra <atish.patra@oracle.com>
Date: Thu Sep 15 14:54:40 2016 -0600
sparc64: Fix cpu_possible_mask if nr_cpus is set
This is a small change that reverts very easily on top of 5.18: there is
just one trivial conflict. Once reverted, both CPUs work again.
Maybe this is related to the fact that the CPUs on this system are
numbered CPU0 and CPU2 (there is no CPU1)?
Here is /proc/cpuinfo on a working kernel:
% cat /proc/cpuinfo
cpu : TI UltraSparc II (BlackBird)
fpu : UltraSparc II integrated FPU
pmu : ultra12
prom : OBP 3.23.1 1999/07/16 12:08
type : sun4u
ncpus probed : 2
ncpus active : 2
D$ parity tl1 : 0
I$ parity tl1 : 0
cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis
Cpu0ClkTck : 000000001ad31b4f
Cpu2ClkTck : 000000001ad31b4f
MMU Type : Spitfire
MMU PGSZs : 8K,64K,512K,4MB
State:
CPU0: online
CPU2: online
And on a broken kernel:
% cat /proc/cpuinfo
cpu : TI UltraSparc II (BlackBird)
fpu : UltraSparc II integrated FPU
pmu : ultra12
prom : OBP 3.23.1 1999/07/16 12:08
type : sun4u
ncpus probed : 2
ncpus active : 1
D$ parity tl1 : 0
I$ parity tl1 : 0
cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis
Cpu0ClkTck : 000000001ad31861
MMU Type : Spitfire
MMU PGSZs : 8K,64K,512K,4MB
State:
CPU0: online
Let me know if you need any more info.
Thanks,
Nick
next reply other threads:[~2022-07-12 5:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-12 5:38 Nick Bowler [this message]
2023-01-20 3:15 ` PROBLEM: Only one CPU active on Ultra 60 since ~4.8 (regression) Nick Bowler
2023-01-21 13:31 ` Linux kernel regression tracking (Thorsten Leemhuis)
2024-03-22 4:57 ` Nick Bowler
2024-03-28 19:36 ` Linux regression tracking (Thorsten Leemhuis)
2024-03-28 20:09 ` Linus Torvalds
2024-03-28 21:08 ` Nick Bowler
2024-03-29 9:44 ` Sam Ravnborg
2024-03-29 20:11 ` Nick Bowler
2024-03-30 9:16 ` Sam Ravnborg
2024-04-05 15:05 ` Andreas Larsson
2023-01-21 13:24 ` Linux kernel regression tracking (#adding)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CADyTPEwt=ZNams+1bpMB1F9w_vUdPsGCt92DBQxxq_VtaLoTdw@mail.gmail.com' \
--to=nbowler@draconx.ca \
--cc=atish.patra@oracle.com \
--cc=sparclinux@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).