"John Hawkes" writes:
>I have downloaded, patched, and built the latest gcc, version 2.95.3,
>and I used that gcc to build linux-2.4.2 and linux-2.4.2+profiling
>kernels. Both kernels booted, and the profiling kernel does appear to
>function without crashing the system.
I had a similar problem. I reported it on the list a couple of weeks
ago, but it might have gotten lost (I didn't see a response). Here's
my post again...
From: Jeremy Elson <jelson@xxxxxxx>
To: kernprof@xxxxxxxxxxx
Subj: acg mode causing reboots?
Date: Sat, 03 Mar 2001 00:22:49 -0800
-----------------
Hi,
First off I'd like to thank you for kernprof specifically, and for all
your Linux support & enthusiasm general, and even more generally for
just being a cool company for many years.
I'm having a problem with the 2.4.1 kernel patch of kernprof. It
seems that sometimes, when I start collecting profiling samples in
ACG-mode (i.e., kernprof -t acg, then kernprof -b), the machine will
reboot within 10 seconds. This doesn't happen until I activate
profiling: the machine runs fine with profiling support in the kernel
but not active. And the machine seems to run find when kernprof is
active in PC mode. One time, I did successfully collect ACG samples,
but many other times I get these reboots instead.
Some additional background:
a) I am using the latest prerelease of GCC/EGCS (gcc version 2.95.3
20010219 (prerelease)), plus your one-line patch.
b) I am using kernel 2.4.1 + kernprof patch 0.8 for 2.4.1
c) I am using kernprof userland utils v1.1
d) all 3 options for profiling are on in the kernel (frame ptrs,
profiling support [not a module], and the char device)
The first time I tried kernprof, the machine rebooted when collecting
acg samples. I then went into /usr/src/linux, saved my .config, did
"make mrproper", and tried again - and everything started working! I
successfully collected call-graph data and viewed it with 'gprof'. I
thought that perhaps there had been some old object files left around
the first time, or an old makefile that was still omitting the frame
pointer.
Then, I added my new device driver to the kernel (the driver is very
stable, but doesn't perform as well as I need - hence kernprof),
recompiled. Once again the reboots started: I'd type "kernprof
-b", and within 10 seconds I get a reset. I tried the make mrproper
trick again but the reboots are still happening.
Any ideas?
Regards,
Jeremy
[ and a few days later...]
Hi again,
I tried recompiling the kernel a couple of more times and it seems
that it does work sometimes, with some random combination of kernel
options. The current (now working) configuration has SMP support
compiled in. Are there any known issues with UP kernels + kernprof?
-Jer
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