debugging in hardware

[Sprajc, Barry]

One nasty debugging pitfall I've run into while trying to debug in hardware
( using L3fwd16) is the following:

If a thread issues a read_lock or write_lock command and a breakpoint
happens before an
unlock occurs, the sram signal gets lost and the thread sits forever waiting
for the signal, 
so following instructions which issue an unlock command never occur,  all
other threads
who issues a read/write command never complete and wait forever on a
read/write lock, 
and the issuing thread never continues.  The only way I've been able to get
past this problem
 is to reset the card.

/b

> -----Original Message-----
> From:	Heaton, Eric D [SMTP:eric.d.heaton at intel.com]
> Sent:	Thursday, November 30, 2000 9:14 AM
> To:	'Alok Kumar'; ixp1200 at CS.Princeton.EDU; Brandewie, Dirk J
> Subject:	RE: debugging in hardware
> 
> I know we've seen problems when inserting breakpoints in hardware.
> sometimes the Microengines get into an undefined state for reasons mostly
> related to either:
> 
> 1. Getting the Microengines out of sync with each other (i.e. when you set
> a
> breakpoint in one Microengine, the other Microengines don't stop
> immediately, but only stop after their respective, currently running,
> threads swap out) or..
> 
> 2. Setting breakpoints while the IXP1200 is trying to receive or transmit
> packets.  This point is due to the fact that the reference designs aren't
> as
> robust as one might like... they are, however, a very good starting point
> to
> get a feel for the IXP1200 and to start developing your own applications.
> 
>   -- Eric Heaton --
> 
> -----Original Message-----
> From: Alok Kumar [mailto:alok at cs.utexas.edu]
> Sent: Wednesday, November 29, 2000 3:30 PM
> To: ixp1200 at CS.Princeton.EDU
> Subject: debugging in hardware
> 
> 
> Hi,
> 
> I have run the reference design pfwd8_1f_16rx_6tx on hardware. I am
> eventually successful in getting packets through it but here are some
> problems I am getting. If anyone has any thoughts or comments on it,
> please, let me know.
> 
> 1. When I use the Intel's latest release (version 1.1),  the packets
> greater than 64 bytes are not forwarded correctly. In version 1.0, there
> is no such problem. I downloaded pfwd8_1f_16rx_6tx in both the cases.
> 
> 2. When I try to debug code in hardware by inserting breakpoint to follow
> the execution of code, it does not forward any packet but rather go to
> some undesirable state. This problem happens in both the version.
> 
> If I use reference design of version 1.0 and do not insert any breakpoints
> in code, I get packets forwarded as expected.
> 
> If anyone has successfully run reference designs from version 1.1 or
> successfully followed code execution in hardware, please, let me know.
> 
> Thanks
> Alok
> 
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