Gary,
I think I mentioned it in the release note.
In this version all debug logic has been changed to use
the pr_xxx() support in the kernel. It's called dynamic
printk.
the documentation for this is in the menuconfig (??).
run make menuconfig, in the kernel hack section look
for dynamic debug. Basically you have to use debugfs
to enable/disable printk. It can be done per file. In 2.6.30
you can do it per line.
On Wed, Jun 24, 2009 at 2:40 AM, <gary.m...@bull.com> wrote:
>
> I have recently applied the 2.6.29 perfmon2 patches to the Fedora 11 2.6.29
> kernel (plus a few other patch sets). They seemed to go in pretty well and
> the kernel rebuilt and booted without problems. I have also installed
> copies of libpfm, papi and HPCToolkit on this system.
>
> Papi seems to work fine and hpcrun-flat also produces good results. But
> when I use hpcrun it executes but never collects any samples. Using the
> hpcrun and papi debug information (plus some messages I added), I think I
> have identified why no samples are collected. The traces show that the
> hpcrun overflow event handler is being called each time that an overflow
> occurs. It is passed an overflow_vector which has a value of 0x20000 and
> then passes this overflow_vector to the PAPI function '
> PAPI_get_overflow_event_index'. This PAPI function gives back a successful
> return but an event count of zero so the handler never calls the code to
> record the event. I also have a test system which has perfctr installed in
> the kernel and hpcrun works correctly on this system. The debug data on
> that system shows an overflow_vector of 0x1 which causes the above
> mentioned PAPI function to return an event count of one.
>
> The overflow_vector is obtained (at least in the perfmon PAPI substrate)
> from a message returned by a read on the PMU fd.
>
> So I decided the next place to look would be in the perfmon2 debug messages
> which I have found before in the kernel message buffer. I ran 'pfdbg --on
> --ovfl-on' and it set the file /sys/kernel/perfmon/debug to 3 to enable
> debug prints. I ran my test again but no messages in the dmesg output. So
> I went looking at the perfmon define macros and found that they require
> 'CONFIG_PERFMON_DEBUG' to be set. So I looked in my kernel config and
> found this value set to 'y'. I then noticed that the perfmon macros use
> 'pr_debug' so I went and found that in the file 'include/linux/kernel.h'.
> It is defined as follows:
>
> #if defined(DEBUG)
> #define pr_debug(fmt, ...) \
> printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
> #elif defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
> #define pr_debug(fmt, ...) do { \
> dynamic_pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
> } while (0)
> #else
> #define pr_debug(fmt, ...) \
> ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
> #endif
>
> So I added a '#define DEBUG 1' to the front of file perfmon_kern.h in the
> patch file and rebuilt my kernel again. This did not help, I still do not
> get any perfmon2 kernel debug messages.
>
> What have I missed ???
>
> Thanks
> Gary
>
>
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