Hello Chris,
chris chriss wrote:
I'm trying to test the cache on my beagle with a snapshot from the git tree today. I tried it out by loading a file from the mmc with dcache off and then dcache on. I didn't see any difference in speed. After reading this commit (http://git.denx.de/?p=u-boot.git;a=commit;h=95c6f6d), I expected to see a performance improvement.
Here a log which actual reloacte code from Albert Aribaud and my fix patch for the beagle on the beagle board:
170.880 U-Boot 2010.09-00102-g456a0da-dirty (Oct 05 2010 - 14:41:10) 170.880 170.920 OMAP3530-GP ES3.0, CPU-OPP2, L3-165MHz, Max CPU Clock 600 mHz 170.920 OMAP3 Beagle board + LPDDR/NAND 170.960 I2C: ready 170.960 DRAM: 128 MiB 171.000 NAND: 256 MiB 174.000 In: serial 174.000 Out: serial 174.000 Err: serial 174.000 Beagle Rev C1/C2/C3 174.360 Die ID #00b000030000000004013f8a1700900c 175.200 Hit any key to stop autoboot: 0 175.440 OMAP3 beagleboard.org # 178.280 OMAP3 beagleboard.org # ica off 178.280 Instruction Cache is OFF 180.480 OMAP3 beagleboard.org # dca off 180.480 Data (writethrough) Cache is OFF 183.520 OMAP3 beagleboard.org # echo start ; nand read 80800000 0 7000000 ; echo stop 0.000 start 0.000 0.000 NAND read: device 0 offset 0x0, size 0x7000000 114.040 NAND read from offset 0 failed -74 114.040 117440512 bytes read: ERROR 114.040 stop 135.880 OMAP3 beagleboard.org # ica on 135.880 Instruction Cache is ON 138.280 OMAP3 beagleboard.org # echo start ; nand read 80800000 0 7000000 ; echo stop 0.000 start 0.000 0.000 NAND read: device 0 offset 0x0, size 0x7000000 95.120 NAND read from offset 0 failed -74 95.120 117440512 bytes read: ERROR 95.120 stop 160.880 OMAP3 beagleboard.org # dca on 160.880 Data (writethrough) Cache is ON 164.600 OMAP3 beagleboard.org # ica on 164.600 Instruction Cache is ON 166.080 OMAP3 beagleboard.org # echo start ; nand read 80800000 0 7000000 ; echo stop 0.000 start 0.000 0.000 NAND read: device 0 offset 0x0, size 0x7000000 26.680 NAND read from offset 0 failed -74 26.680 117440512 bytes read: ERROR 26.680 stop
This is a capture of how I tested it...
<capture>
OMAP3 beagleboard.org # mmc init 1 mmc1 is available OMAP3 beagleboard.org # dcache Data (writethrough) Cache is OFF OMAP3 beagleboard.org # fatload mmc 0:1 0x80000000 uImage.bin reading uImage.bin
3852836 bytes read OMAP3 beagleboard.org # dcache on Data (writethrough) Cache is ON OMAP3 beagleboard.org # fatload mmc 0:1 0x80000000 uImage.bin reading uImage.bin
3852836 bytes read OMAP3 beagleboard.org #
</capture>
How did you measured the time between start an end?
Maybe uImage.bin is a little bit to small for seeing some effect?
bye, Heiko