Looked at where the processor spends its time when browsing the web.
Hardware configuration:
OLPC Beta 2 machine
Linksys USB200M USB 10/100 for ethernet connection
4GB memorex Mini Travel Drive for storage of image
Software configuration:
/tmp/olpc-redhat-stream-development-build-299-20070308_1417-devel_ext3.img
kernel-2.6.21-20070309.olpc1p.dc5079fafb767e4
oprofile-0.9.2-3.fc6
Started OProfile then started the browser up pointed at
www.redhat.com. Then went to the "Red Hat Magazine" link and read two
articles one about Green phone and the other about iostat. Shutdown
OProfile.
# opreport -t 5
CPU: CPU with timer interrupt, speed 0 MHz (estimated)
Profiling through timer interrupt
TIMER:0|
samples| %|
------------------
19279 50.6077 vmlinux-20070309.olpc1p.dc5079fafb767e4
11959 31.3926 Xorg
TIMER:0|
samples| %|
------------------
11121 92.9927 libfb.so
372 3.1106 Xorg
299 2.5002 libexa.so
153 1.2794 libc-2.5.so
12 0.1003 amd_drv.so
1 0.0084 libextmod.so
1 0.0084 evdev_drv.so
6177 16.2147 python
TIMER:0|
samples| %|
------------------
2619 42.3992 libxul.so
756 12.2390 libpython2.4.so.1.0
570 9.2278 libc-2.5.so
566 9.1630 libmozjs.so
223 3.6102 libcairo.so.2.10.3
194 3.1407 libgobject-2.0.so.0.1200.9
150 2.4284 libglib-2.0.so.0.1200.9
145 2.3474 libpthread-2.5.so
136 2.2017 libnspr4.so
...
I didn't have the debuginfo around so I just looked for instructions
locations getting lots of samples and then looked at the disassembled
libfb.so. There are definitely some Xorg/libfb.so hotspots, six
location have 20% of the samples for libfb.so:
# opreport -t 5 -d /usr/bin/Xorg |sort -nrk 2|more
00000000 11121 92.9927 libfb.so (no symbols)
00015820 507 4.5589 idiv preceding this
0001584a 506 4.5500 idiv preceding this
000157f8 468 4.2083 idivl preceding this
000157b2 433 3.8935 idivl preceding this
0000fc04 296 2.6616
0000fc0b 132 1.1869
0001592c 109 0.9801 back to back imul
000158b5 108 0.9711
000159b3 107 0.9621
libfb.so is spending about 17% of the time in Xorg (about 5% overall,
.31*17%) in divides. Divides are very on the Geode expensive; idiv are
24 cycles and the idivl are 40 cycles. Is there some way to turn this
into multiply and shift right operations? The multiply is 4 or 7
cycles and the shift is 2 cycles.
Looking for libxul.so hotspots. It doesn't seem to have any hotspots:
# opreport -d /usr/bin/pythong |sort -nrk 2|more
00000000 2619 42.3992 libxul.so (no symbols)
00000000 756 12.2390 libpython2.4.so.1.0 (no symbols)
00000000 566 9.1630 libmozjs.so (no symbols)
0015b3b7 78 2.9782
00019277 26 3.4392
0000ba07 17 3.0035
001620b4 16 0.6109
001620e0 11 0.4200
001620de 10 0.3818
...
-Will
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