SPRAC21A June 2016 – June 2019 OMAP-L132 , OMAP-L138 , TDA2E , TDA2EG-17 , TDA2HF , TDA2HG , TDA2HV , TDA2LF , TDA2P-ABZ , TDA2P-ACD , TDA2SA , TDA2SG , TDA2SX , TDA3LA , TDA3LX , TDA3MA , TDA3MD , TDA3MV
To understand the total available DDR bandwidth of the system for the interleaved versus non-interleaved mode of operation, it is required to have a multi-initiator test. In this synthetic test, the following initiators are used for the interleaved versus non-interleaved case. The DSS reporting an Underflow error was used as a reference point to know when the DDR bandwidth is maximized out in the system.
NOTE
In the current experiment for the non-interleaved case, the data is not routed through EMIF2 and the system is assumed to be a single, 32-bit DDR system.
Non-Interleaved initiators:
Interleaved initiators:
The throughput is measured using statistic collectors available in the L3 at the EMIF1_probe and EMIF2_probe as shown in Figure 54. The statistic collector registers are read every 100 µs for 5 seconds and the bandwidth data is obtained by dividing the number of bytes transferred in 100 µs divided by 100 µs.
The ideal throughput for DDR3 running at 532 MHz is:
Table 91 shows that when the EMIF FIFOs are fully occupied then the system can expect a 10-15% boost in performance by configuring the EMIFs in interleaved mode versus a non-interleaved mode.
Also note that this is a synthetic test to measure the maximized out EMIF throughput. When executing a real system use-case, you can expect around 55-60% DDR utilization.
Non-Interleaved (One 32-Bit Memory) | Interleaved (Two 32-Bit Memory) | |||||
---|---|---|---|---|---|---|
EMIF1 Bandwidth | EMIF2 Bandwidth (No Traffic to EMIF2) | Total | EMIF1 Bandwidth | EMIF2 Bandwidth | Total | |
Maximum Bandwidth (MB/s) | 3121.60 | NA | 3121.60 | 3650.88 | 3642.88 | 7293.76 |
Average Bandwidth (MB/s) | 2458.25 | NA | 2458.25 | 3035.51 | 3045.00 | 6080.51 |
Maximum DDR Utilization | 73% | NA | 73% | 86% | 86% | 86% |
Average DDR Utilization | 58% | NA | 58% | 71% | 72% | 71% |