Messages in this thread | | | Date | Thu, 24 Apr 2014 15:20:46 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] printk: Print cpu number along with time |
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On Fri, Apr 25, 2014 at 12:12:06AM +0200, Jiri Kosina wrote: > On Thu, 24 Apr 2014, Greg Kroah-Hartman wrote: > > > > +#ifdef CONFIG_PRINTK_CPU > > > + if (!buf) > > > + return snprintf(NULL, 0, "[%5lu.000000,%02x] ", > > > > %02x for a cpu? What happens on machines with 8k cpus? > > Ummm ... what issue do you see here, Greg? It'll print 0x1f40, no?
Yes, just not be as "pretty" and aligned properly :)
> > And is this really an issue? Debugging by using printk is fun, but not > > really something that people need to add a cpu number to. Why not just > > use a tracepoint in your code to get the needed information instead? > > Well, if you have dmesg dump from panic that happens every other year, and > you have to do post-mortem analysis on it, I am pretty sure you would love > to be able to figure out how the stack traces would look like without > inter-CPU interleaving. And I am pretty sure you wouldn't want to > insert/enable a tracepoint and wait another two years for the bug to > trigger again.
Fair enough, and the multi-oops message drives that home.
But does this break things like 'dmesg --human' mode that is in util-linux?
thanks,
greg k-h
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