SCMiMX6Q Performance issue compared to iMX6SOLO

manojsampathkum — Wed, 28 Mar 2018 10:59:56 GMT

I am working on QWKS-SCMiMX6Q board for performance needed project. Right now I am evaluating the SCMiMX6Q using the qwks board with L4.1.15 kernel and krogoth release. For various reasons, we need to move SCMiMX6q against our own iMX6SOLO board. While evaluating the performance of SCMiMX6q we found it drastically lags in performance compared to our iMX6SOLO board. The test was conducted using the standard benchmark tools to analyze the performance of DDR. SCM is having a RAM of 1GB LPDDR and our iMX6SOLO is also having 1GB DDR3 RAM. Both processors operate on 32-bit mode and same DDR-Frequency of 400MHz.

BENCHMARK TOOLS used:

LMBENCH
MBW
STREAM

PERFORMANCE ANALYSIS:

LMBENCH was used to analyze LATENCY

MBW and STREAM were used to analyze BANDWIDTH

	LMBENCH	STREAM	MBW
SCMiMX6Q	57.240ns	592.77 MB/sec	274.556 MiB/s
iMX6SOLO	42.639ns	1104.97 MB/sec	685.166 MiB/s

SCMiMX6Q is less than half speed of our iMX6SOLO board.

the Actual results must be SCMiMx6q should give more performance compared to SOLO.I suspect the performance is due to the mismatch of the clock frequency for mmdc controllers in SCM.

CLOCK:

mmdc_ch1_axi 528000000

mmdc_ch0_axi 396000000

Actual suggested frequency rate for DDR is 400 MHZ but why there is a difference. What is the reason behind huge performance difference in SCM.It will affect our products also.I am really running out of ideas.

Any Patches or fix for this issue

Hoping for a faster and better guidance

Re: SCMiMX6Q Performance issue compared to iMX6SOLO

igorpadykov — Thu, 29 Mar 2018 06:00:50 GMT

Hi Manoj

in general this may be explained by different burst size as described on

LPDDR2 performance vs DDR3L

One can try to further analyze it with mmdc profiling described on above link

Best regards
igor
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topic Re: SCMiMX6Q Performance issue compared to iMX6SOLO in i.MX Processors

SCMiMX6Q Performance issue compared to iMX6SOLO

Re: SCMiMX6Q Performance issue compared to iMX6SOLO