Messages in this thread |  | | | Date | Mon, 3 Jul 2000 15:36:25 -0700 (PDT) | | From | Chris Lattner <> | | Subject | Re: [PATCH #2] console lock grabbed too early in printk... |
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> > is not held (which is the only case that matters, because otherwise, > > access would block on the console_lock currently), we have the following > > (for the x86 at least, the others are similar): > > > > spin_lock: > > "xchgb %b0,%1"
> The xchgb is a locked bus access so takes an awful lot longer, especially on > earlier cpus
Okay, so especially in SMP systems where you actually have to lock a bus... the xchg could take a few cycles... but the question remains, how frequently is printk called? Is it called "that often" that even 100 cycles can't be spared?
-Chris
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