Fiasco built-in profiling

Stefan Scheler stefan at scheler.com
Tue May 1 09:18:47 CEST 2007


Hello,

> I fear nobody has tried profiling in some time. Could you find out
> yourself what's going on and report?

Well, here we go. I meanwhile managed to get that working but
encountered several problems. Especially problem 2 seems a bit odd to
me. Feedback is greatly appreciated.

I'm cc'ing also Martin Pohlack, because I was told he is the man for
profiling :).

1) gprof wants to allocate larger junks of memory than alloc() in class
Buddy_t_base can currently handle (limit 65535 bytes). So trying to
allocate larger pieces of memory, alloc() returned always 0 bytes.
Increasing NUM_SIZES von 8 to 10 seems to fix this issue.

2) Next, fiasco crashes executing this line of code:

s_scale = (int)(( (float) monsize / o ) * SCALE_1_TO_1);

with the following error message:

KERNEL: Denying 0.0 to send fault message (pfa=00000008, code=00000000)
to 7ff.7f

KERNEL: 0.0 (tcb=c0000000) killed:
Unhandled trap

EAX 000000fe EBX 00000000 ECX f0055efe EDX 00000001
ESI 00000000 EDI 00000204 EBP c0000718 ESP c000070c
EIP f000477e EFLAGS 00210282
CS 0008 SS 0010 DS 0023 ES 0023 FS 0023 GS 0023
trap 14 (Page Fault), error 00000000, from kernel mode
page fault linear address 00000008

I really don't understand this one. I can execute this statement
perfectly well in a separate c program on my machine (with monsize =
189784, o = 379568 and SCALE_1_TO_1 = 65536). I "fixed" this by setting
s_scale manually to the calculation's result of 32768.

3) The gzipped and uuencoded output thing does not produce any output
here. I didn't have the time to look into this until now. For now I
disabled this and send the data in a hexadecimal encoding over the
serial line.

Stefan

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