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Reduced video bus transfer speed on Sam440ep after update 3

Posted: Wed Jan 04, 2012 9:19 pm
by jostein_aarbakk
Ragemem shows me that the video bus transfer speed between the central RAM and video RAM have been reduced in OS 4.1 update 3/4 compared to update 2.
Is it possible to get the higher video bus speed back?
(I don't know if this is related, but the same executable of DVPlayer uses around 20% more CPU in update 3&4 compared to update 2.).

Thanks in advance for your help.

RageMem shows these numbers (update 3 & 4):
---> VIDEO BUS <---
READ: 39 MB/Sec
WRITE: 53 MB/Sec

..while on update 2 they were:
---> VIDEO BUS <---
READ: 41 MB/Sec
WRITE: 63 MB/Sec

Details of my system:
o ACube SAM440EP 667MHz (mini-ITX) with 512 MB RAM and onboard Radeon M9 gfx chip.
The firmware is upgraded to uboot 1.3.1d + ACubes PCI firmware update for that increases the PCI unit's clock speed (that's how I got 63 MB/sec write speed).
o Acubes setup tool for Sam440ep (increases VIDEO BUS read speed from 14 MB/sec). This is no firmware upgrade; Only software.
o Amiga OS4.1 update 4.

Re: Reduced video bus transfer speed on Sam440ep after updat

Posted: Mon Jan 16, 2012 3:28 pm
by m3x
That's normal, now rtg.library use DMA instead of CPU (where possible) to transfer data from main ram to video ram.
Ragemem measures only CPU speed transfer, not DMA speed transfer.

I suggest you to do tests with gfxbench2d from OS$Depot.

Re: Reduced video bus transfer speed on Sam440ep after updat

Posted: Sat Jan 21, 2012 12:45 am
by jostein_aarbakk
m3x wrote:rtg.library use DMA instead of CPU (where possible) to transfer data from main ram to video ram.
Thanks for your reply. DMA sounds good.
However, I have compared the results from GfxBench2d on update 4 with the results from update 2, and the RAM->VRAM speed seems to be lower on update 4 compared to update 2 (except for WritePixelArray, which is a lot faster).
VRAM->RAM seems faster on update 4 compared with update 2, which is good (except for useMemcpy, which is slightly slower).

The hardware, screenmode and test conditions were identical on both tests.
Here they are:

Copy from RAM to VRAM:
Transfer size: 15452160 bytes

Update 2 Update 4
copy32: 63.009 MiB/s 53.381 MiB/s
copy64: 55.838 MiB/s 52.386 MiB/s
copy64f: 63.218 MiB/s 53.482 MiB/s
copy64x2: 62.984 MiB/s 53.385 MiB/s
copy64fx2: 63.219 MiB/s 53.488 MiB/s
copy64fx2PF: 56.008 MiB/s 53.503 MiB/s
copy64fx4PF: 63.206 MiB/s 53.481 MiB/s
useMemcpy: 31.548 MiB/s 26.490 MiB/s
useExecCopyMem: 55.851 MiB/s 53.392 MiB/s
copyToVRAM: 63.204 MiB/s 53.494 MiB/s
WritePixelArray: 62.760 MiB/s 90.966 MiB/s

Copy from VRAM to RAM:
Transfer size: 15452160 bytes

Update 2 Update 4
copy32: 20.961 MiB/s 26.382 MiB/s
copy64: 22.791 MiB/s 28.762 MiB/s
copy64f: 22.857 MiB/s 29.998 MiB/s
useMemcpy: 11.023 MiB/s 10.279 MiB/s
useExecCopyMem: 20.958 MiB/s 26.377 MiB/s
copyFromVRAM: 22.860 MiB/s 30.309 MiB/s
ReadPixelArray: 21.882 MiB/s 35.390 MiB/s

System Information (for update 2):
OS: AmigaOS Release 4.1 - Update 2
Motherboard: Sam440EP
CPU: AMCC PPC440EP, 1.3 @ 666.667 MHz
L1 Cache Size: 32768, L2 Cache Size: 0, L3 Cache Size: 0
Total RAM: 512 MiB
External Bus (FSB) Speed: 133.333 MHz
Exec.library version: 53.12
Graphics.library version: 53.4
Intuition.library version: 53.30
Picasso96API.library version: 2.356
Rtg.library version: 41.4340
Opening screen: P96-0:Radeon M9:1280x1024
Board name: Radeon M9
Product ID: 0x4c66 Vendor ID: 0x1002 SubProduct ID: 0x4c66 SubVendor ID: 0x1002
Board driver: Unknown (0, 0)
Chip driver: Unknown (0, 0)
VRAM: 63.9844 MiB
Display mode: 1280x1024@60 (32 bpp)

System Information (for update 4. Only the values that GfxBench displays with other values for update 4):
OS: AmigaOS Release 4.1 - Update 4
Exec.library version: 53.25
Intuition.library version: 53.35
Picasso96API.library version: 2.359
Rtg.library version: 41.4355
Board driver: PCIGraphics.card (53, 1)
Chip driver: ATIRadeon.chip (53, 23)