Re: [PATCH 6/8] SGI x86_64 UV: Limit the number of microcode messages

From: Mike Travis
Date: Mon Oct 26 2009 - 14:25:39 EST




Dmitry Adamushko wrote:
2009/10/24 Tigran Aivazian <tigran@xxxxxxxxxxxxxxxxxxxx>:
On Sat, 24 Oct 2009, Dmitry Adamushko wrote:
- printk(KERN_INFO "microcode: CPU%d sig=0x%x, pf=0x%x,
revision=0x%x\n",
+ if (cpu_num < 4 || !limit_console_output(false))
+ printk(KERN_INFO
+ "microcode: CPU%d sig=0x%x, pf=0x%x,
revision=0x%x\n",
cpu_num, csig->sig, csig->pf, csig->rev);

Hmm, I guess we wouldn't lose a lot by simply removing those messages
completely. Per-cpu pf/revision is available via /sys anyway.
The reason for printing them is that the pf (possibly others?) can change by the update and so the log has this info handy.

We might store the old sig/pf/revision set as well, export them via
/sys or/and print them at update-to-new-microcode time.

If it's really so useful to have this info in the log and, at the same
time, to avoid the flood of messages (which, I guess for the majority
of systems, are the same) at startup time, we might delay the printout
until the end of microcode_init(). Then do something like this:

microcode cpu0: up to date version sig, pf, rev // let's say,
it was updated by BIOS
microcode cpus [1 ... 16] : update from sig, pf, rev to sig, pf2, rev2.

Anyway, my humble opinion, is that (at the very least) the current
patch should be accompanied by a similar version for amd.

I could add it for AMD but I can't test it, and I'm always reluctant to
change things I can't verify.

Thanks,
Mike



Kind regards
Tigran


-- Dmitry
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