Where olpc machine spending time when using web broswer

[Vladimir Makarov]

Dan Williams wrote:

>On Tue, 2007-03-13 at 12:04 -0500, Vladimir Makarov wrote:
>  
>
>>William Cohen wrote:
>>
>>    
>>
>>>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.
>>>      
>>>
>>I don't know what version of gcc and options were used to compile the 
>>packages.  If somebody points me where to look at this, I could be more 
>>sure.  It looks to me that the packages were compiled without usage of 
>>tunnning gcc to geode.  The div and mod insn are expensive in geode. 
>> Usage of div or shifts are choosen in gcc expmed.c and this is directed 
>>by costs defined by -mtune or -march.
>>
>>I already did gcc tunning to geode (pipeline description, code costs, 
>>i386 port parameter values) and submitted it to the gcc mainline.  As I 
>>know Jakub Julinek was going to backport this code to redhat gcc.  So I 
>>can guess that if the right compiler and options are used, it will make 
>>code faster (and several % smaller because -mtune=geode generates 
>>smaller code that any other tuning).
>>    
>>
>
>I seem to recall that we have a gcc available that does geode tuning.
>What's missing is to change the RPM_OPT_FLAGS in the olpc-1 buildroots
>and then fork & recompile packages from package-cvs that we want to
>optimize with geode.  That by definition means that we try to recompile
>only the smallest set of packages we can since it's a branch off of FC6.
>
>We'll need to check up on this further.  Vladimir, can you verify that
>the version of gcc in FC6-updates right now does Geode optimizations for
>us?
>
>  
>
Sorry for slower response.  Yes, Jakub added the patch for fedora 6 
update gcc.