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Re: kdb on SMP

To: Keith Owens <kaos@xxxxxxx>
Subject: Re: kdb on SMP
From: Hua Qin <qinhua@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 25 Mar 2003 09:36:05 -0500 (EST)
Cc: kdb@xxxxxxxxxxx
In-reply-to: <27517.1048347022@xxxxxxxxxxxxxxxxxxxxx>
Sender: kdb-bounce@xxxxxxxxxxx
Keith, 

I have to go back to "bp" and "bpa".
You said "bp" and "bpa" are same. Meaning  the current "bp" is a  global
breakpoint for all cpus?

I did some tests, set a break point on cpu 4 by using "bp", then "go".
later, when the break point were hit, it was on cpu 3. 

Is that correct way for "bp"?
Thanks!
Hua




On Sun, 23 Mar 2003, Keith Owens wrote:

> On Sat, 22 Mar 2003 09:25:43 -0500 (EST), 
> Hua Qin <qinhua@xxxxxxxxxxxxxxxxxxxxx> wrote:
> >So "bpa" will have the same problem? 
> 
> bp and bpa are the same for software breakpoints.
> 
> >How about "bph" and "bpha", since they are
> >using Pentium debug registers other that int3 mechanism, they don't have
> >these problem.
> 
> bpha installs the hardware breakpoint on all cpus, bph only installs on
> one cpu but is not much use when you do not know which cpu you will be
> executing on.
> 
> The current kdb code for handling two cpus dropping into kdb at the
> same time has races.  Sonic Zhang mailed some test patches recently,
> see ftp://oss.sgi.com//projects/kdb/download/v4.0/kdb-smphdr*.  I have
> not had time to try them yet.
> 
> 
> 


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