Re: [Linux-fbdev-devel] savagefb

[Alex S. <ale...@co...>]

hi,

thanks for the link, the savagefb driver appears to be working : )

one other question though, what sort of bandwidth are people getting 
writing to their framebuffers. i am running savagefb on a via pro savage 
chipset (PN133T) which has shared memory (a part of main memory is used as 
the framebuffer) and i ran a little test program to test the bandwidth and 
it seems to be quite slow at 32bit colour modes.

the results are as follows:

fb_ptr:401a9000
resolution:640x480x8 virtual resolution:640x480 framebuffer size:307200
frames:500 sec:1.204243 frames/s:415.198594 Mpix/s:127.549008 MB/s:127.549008
fb_ptr:401f4000
resolution:640x480x16 virtual resolution:640x480 framebuffer size:614400
frames:500 sec:2.683917 frames/s:186.294882 Mpix/s:57.229788 MB/s:114.459575
fb_ptr:4028a000
resolution:640x480x32 virtual resolution:640x480 framebuffer size:1228800
frames:500 sec:6.328235 frames/s:79.010972 Mpix/s:24.272171 MB/s:97.088683
fb_ptr:401d3000
resolution:800x600x8 virtual resolution:800x600 framebuffer size:480000
frames:500 sec:1.939521 frames/s:257.795610 Mpix/s:123.741893 MB/s:123.741893
fb_ptr:40248000
resolution:800x600x16 virtual resolution:800x600 framebuffer size:960000
frames:500 sec:4.518773 frames/s:110.649506 Mpix/s:53.111763 MB/s:106.223526
fb_ptr:40332000
resolution:800x600x32 virtual resolution:800x600 framebuffer size:1920000
frames:500 sec:10.488265 frames/s:47.672327 Mpix/s:22.882717 MB/s:91.530868
fb_ptr:4021e000
resolution:1024x768x8 virtual resolution:1024x768 framebuffer size:786432
frames:500 sec:3.384868 frames/s:147.716248 Mpix/s:116.168784 MB/s:116.168784
fb_ptr:402de000
resolution:1024x768x16 virtual resolution:1024x768 framebuffer size:1572864
frames:500 sec:7.626457 frames/s:65.561243 Mpix/s:51.559459 MB/s:103.118919
fb_ptr:4045e000
resolution:1024x768x32 virtual resolution:1024x768 framebuffer size:3145728
frames:500 sec:20.687864 frames/s:24.168759 Mpix/s:19.007086 MB/s:76.028342

the test program malloc's a chunk of memory and mmap's /dev/fb and the 
memory is copied to the framebuffer via memcpy and timed and the results 
are printed out. mtrr is enabled by default by the savagefb driver and the 
system is a PIII 1GHz, 120MB RAM 8MB framebuffer running kernel-2.4.19-pre7 
with the savagefb patch. is the shared memory making this slow ? or is it 
something else that i have missed ?

one other thing i noticed is that when i change timings (from "1024x768-60" 
to"1024x768-72") the results change and "1024x768-72" seems to be always 
faster (30fps) than "1024x768-60". don't know why this is, but i will look 
into it some more.

any help would be appreciated.

cheers,

alex

At 10:58 PM 04/26/2002, Joachim Steiger wrote:
>take a look at the cvs version from directfb (www.directfb.org)
>in the subdirectory patches/ of the module DirectFB you'll find what
>you need.
>
>have fun.
>
>regards
>
>   roh
>
>
>_______________________________________________
>Linux-fbdev-devel mailing list
>Lin...@li...
>https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel