Where olpc machine spending time when using web broswer

[William Cohen]

William Cohen wrote:
> 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


Re ran the experiment on build 301 and installed the 
xorg-x11-server-debuginfo-1.1.99.3-0.10.2.olpc1.i386.rpm on the olpc machine, so 
I could take a look at where time is being spent in libfb.so.

# opreport -t 1 -l /usr/bin/Xorg
CPU: CPU with timer interrupt, speed 0 MHz (estimated)
Profiling through timer interrupt
samples  %        image name               symbol name
6514     68.1096  libfb.so                 fbFetchTransformed
613       6.4095  libfb.so                 fbFetchPixel_x8r8g8b8
446       4.6633  libfb.so                 fbCompositeSolidMask_nx8x0565mmx
252       2.6349  libfb.so                 fbStore_r5g6b5
169       1.7670  libfb.so                 fbRasterizeEdges
137       1.4325  libfb.so                 fbCompositeSrc_8888x0565mmx
113       1.1815  libfb.so                 fbCopyAreammx
99        1.0351  libfb.so                 mmxCombineOverU

The attached file is a portion of the output from opannotate. There is a group 
of MOD operations that are taking a significant portion of the time. The first 
column is the number of samples and the second column is the percentage.

    398  6.1099 :                        x1 = MOD (x1, pict->pDrawable->width);
    383  5.8796 :                        x2 = MOD (x2, pict->pDrawable->width);
    336  5.1581 :                        y1 = MOD (y1, pict->pDrawable->height);
    355  5.4498 :                        y2 = MOD (y2, pict->pDrawable->height);

Following this there are also some other expensive operations to compute r. and 
put it into buffer[i].

-Will
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