DDR BW Utilization for 720MHZ uP and 532Mhz DDR2? Can I obtain numbers for this?
From presentations, I see for 500Mhz up, DDR 200Mhz, the Utilization is 633 Mhz.
I would like to know what it would be for the speed above.
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DDR BW Utilization for 720MHZ uP and 532Mhz DDR2? Can I obtain numbers for this?
From presentations, I see for 500Mhz up, DDR 200Mhz, the Utilization is 633 Mhz.
I would like to know what it would be for the speed above.
hello,
here are the performance numbers for 720MHz ARM and 266MHz DDR2 (266MHz is the speed that the AM335x DDR2 interface runs):
bw_mem and lat_mem_rd from lmbench. Bw_mem measures throughput during read (rd), write(wr), read+write (rdwr) and copy (cp) operations; and lat_mem_rd measures read latency. 1MB was used as the data size in for bw_mem; for lat_mem_rd a stride (step size in bytes) of 128 bytes was used with a 1MB data size.
Test Name | Units | Linux PSP 04.06.00.07 | Android Devkit 3.0.1 |
bw_mem-rd-1MB | MB/s | 244.82 | 245.78 |
bw_mem-wr-1MB | MB/s | 871.46 | 862.48 |
bw_mem-rdwr-1MB | MB/s | 197.8 | 197.42 |
bw_mem-cp-1MB | MB/s | 179.55 | 176.2 |
lat_mem_rd-stride128-sz50 | ns | 4.21 | 4.211 |
lat_mem_rd-stride128-sz31k | ns | 4.19 | 4.206 |
lat_mem_rd-stride128-sz62k | ns | 12.7 | 12.759 |
lat_mem_rd-stride128-sz125k | ns | 16.18 | 16.261 |
lat_mem_rd-stride128-sz250k | ns | 57.68 | 66.353 |
lat_mem_rd-stride128-sz500k | ns | 219.24 | 221.942 |
lat_mem_rd-stride128-sz1000k | ns | 264.16 |
266.059 |
hi Jeff,
Our key customer compared DDR read speed between AM3352 300MHz(16 bit 266MHz DDR2) and ATMEL SAM9263(ARM926EJ-S) 200Mhz(32 bit 100Mhz SDRAM) , and found that there is no performance improvement as they think there should be at least 2X improvement. Could you please help to provide an analysis on the root cause of this bottlenect? Below is the test date:
AM3352 @300MHZ SAM9263@200MHZ
16BIT 266MHZ DDR2 32BIT 100MHZ SDRAM
bw_mem 1M rd 181.42 MB/s 194.36 MB/s
bw_mem 1M bzero 595.86 MB/s 164.84 MB/s
1) SAM9263(ARM926EJ-S) 200MHZ,32BIT SDRAM,100MHZ,Linux2.6 by bw_mem:
runLmDDRBandwidth.sh
BANDWIDTH MEASUREMENTS
(MB) (MB/s)
---------------
bw_mem 1M rd
1.05 194.36
bw_mem 1M rdwr
1.05 91.31
bw_mem 1M cp
1.05 142.90
bw_mem 1M frd
1.05 139.38
bw_mem 1M fcp
1.05 86.03
bw_mem 1M bzero
1.05 164.84
bw_mem 1M bcopy
1.05 92.32
2). AM3352 300MHZ,VDDCORE = 1.1V,VDDMPU = 1.2V, 16BIT DDR2 RAM,266MHZ,Linux3.2 by bw_mem:
root@am335x-evm:~# runLmDDRBandwidth.sh
BANDWIDTH MEASUREMENTS
(MB) (MB/s)
---------------
bw_mem 1M rd
1.00 181.42
bw_mem 1M rdwr
1.00 152.58
bw_mem 1M cp
1.00 149.68
bw_mem 1M frd
1.00 157.70
bw_mem 1M fcp
1.00 136.41
bw_mem 1M bzero
1.00 595.86
bw_mem 1M bcopy
1.00 199.92