Bernd Walter wrote: > On Fri, Sep 28, 2007 at 07:56:49AM -0700, Darren Pilgrim wrote: >> Jeremy Chadwick wrote: >>> I think what you're not noticing is that the cores are being launched in >>> non-sequential order. 1, 2, 3, 4, 7, 5, 6. This isn't a problem. >> Why they wouldn't be launched sequentially? > > First SMP rule: > Don't expect a specific execution order from things running parallel. > > I don't know the code, but would assume that they are started > sequentially and each core prints it's own line, so they get > disordered. This question bugged me long enough for me to go read some source to find the answer, but I ended up with more questions. I guess that's what I get for reading boot code. :) I know it's basically just a race condition, but where does the race actually occur? In each core's execution of startup instructions leading up to the printf() in init_secondary() or in the assignment of the value returned by PCPU_GET(cpudid)? Where is the data behind PCPU_GET() anyway? I couldn't find it. Is AP launch order random or are there CPU characteristics that result in reproducible non-sequential ordering?Received on Sat Sep 29 2007 - 02:57:37 UTC
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