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changeyourname / pandroid

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Read Latency to external memory is high #9

Open GoogleCodeExporter opened 8 years ago

GoogleCodeExporter commented 8 years ago 
What steps will reproduce the problem?
1. Use lmbench suite - lat_mem_rd binary.
2. look at stride 128, array size 8M. latency is 300 ns.

What is the expected output? What do you see instead?
Since DDR2 is supposed to run at 400 MHz, latency should be ~150ns

What version of the product are you using? On what operating system?
Pandaboard with OMAP4430 ES2.1 chip. Android latest prebuild binaries.

Please provide any additional information below.
lat_mem_rd will try to read some data from buffers allocated in L1/L2/EMEM. Its 
a pretty reliable performance monitoring tool.

Original issue reported on code.google.com by alifa...@gmail.com on 28 Feb 2011 at 10:30