8.3. Runtime Instrumentation Testing - N1SDP

For this test we used the N1 System Development Platform (N1SDP), which contains an SoC consisting of two dual-core Arm N1 clusters.

The following source trees and binaries were used:

• TF-A [v2.9-rc0-16-g666aec401]

• TFTF [v2.9-rc0]

• SCP/MCP Prebuilt Images

Please see the Runtime Instrumentation Testing Methodology page for more details.

8.3.1. Procedure

1. Build TFTF with runtime instrumentation enabled:

   make CROSS_COMPILE=aarch64-none-elf- PLAT=n1sdp \
       TESTS=runtime-instrumentation all
   

2. Build TF-A with the following build options:

   make CROSS_COMPILE=aarch64-none-elf- PLAT=n1sdp \
       ENABLE_RUNTIME_INSTRUMENTATION=1 fiptool all
   

3. Fetch the SCP firmware images:

   curl --fail --connect-timeout 5 --retry 5 \
       -sLS -o build/n1sdp/release/scp_rom.bin \
       https://downloads.trustedfirmware.org/tf-a/css_scp_2.12.0/n1sdp/release/n1sdp-bl1.bin
   curl --fail --connect-timeout 5 \
       --retry 5 -sLS -o build/n1sdp/release/scp_ram.bin \
       https://downloads.trustedfirmware.org/tf-a/css_scp_2.12.0/n1sdp/release/n1sdp-bl2.bin
   

4. Fetch the MCP firmware images:

   curl --fail --connect-timeout 5 --retry 5 \
       -sLS -o build/n1sdp/release/mcp_rom.bin \
       https://downloads.trustedfirmware.org/tf-a/css_scp_2.12.0/n1sdp/release/n1sdp-mcp-bl1.bin
   curl --fail --connect-timeout 5 --retry 5 \
       -sLS -o build/n1sdp/release/mcp_ram.bin \
       https://downloads.trustedfirmware.org/tf-a/css_scp_2.12.0/n1sdp/release/n1sdp-mcp-bl2.bin
   

5. Using the fiptool, create a new FIP package and append the SCP ram image onto it.

   ./tools/fiptool/fiptool create --blob \
           uuid=cfacc2c4-15e8-4668-82be-430a38fad705,file=build/n1sdp/release/bl1.bin \
           --scp-fw build/n1sdp/release/scp_ram.bin build/n1sdp/release/scp_fw.bin
   

6. Append the MCP image to the FIP.

   ./tools/fiptool/fiptool create \
       --blob uuid=54464222-a4cf-4bf8-b1b6-cee7dade539e,file=build/n1sdp/release/mcp_ram.bin \
       build/n1sdp/release/mcp_fw.bin
   

7. Then, add TFTF as the Non-Secure workload in the FIP image:

   make CROSS_COMPILE=aarch64-none-elf- PLAT=n1sdp \
       ENABLE_RUNTIME_INSTRUMENTATION=1 SCP_BL2=/dev/null \
       BL33=<path/to/tftf.bin>  fip
   

8. Load the following images onto the development board: fip.bin, scp_rom.bin, scp_ram.bin, mcp_rom.bin, and mcp_ram.bin.

Note

These instructions presume you have a complete firmware stack. The N1SDP user guide provides a detailed explanation on how to get setup from scratch.

8.3.2. Results

8.3.2.1. CPU_SUSPEND to deepest power level

CPU_SUSPEND latencies (µs) to deepest power level in parallel

Cluster	Core	Powerdown	Wakekup	Cache Flush
0	0	3.44	10.04	0.4
0	1	4.98	12.72	0.16
1	0	3.58	15.42	0.2
1	1	5.24	17.78	0.18

CPU_SUSPEND latencies (µs) to deepest power level in serial

Cluster	Core	Powerdown	Wakekup	Cache Flush
0	0	1.82	9.98	0.32
0	1	1.96	9.96	0.18
1	0	2.0	10.5	0.16
1	1	2.22	10.56	0.16

8.3.2.2. CPU_SUSPEND to power level 0

CPU_SUSPEND latencies (µs) to power level 0 in parallel

Cluster	Core	Powerdown	Wakekup	Cache Flush
0	0	1.52	11.84	0.34
0	1	1.1	13.66	0.14
1	0	2.18	9.48	0.18
1	1	2.06	14.4	0.16

CPU_SUSPEND latencies (µs) to power level 0 in serial

Cluster	Core	Powerdown	Wakekup	Cache Flush
0	0	1.54	9.34	0.3
0	1	1.88	9.5	0.16
1	0	1.86	9.86	0.2
1	1	2.02	9.64	0.18

8.3.2.3. CPU_OFF on all non-lead CPUs

CPU_OFF on all non-lead CPUs in sequence then, CPU_SUSPEND on the lead core to the deepest power level.

CPU_OFF latencies (µs) on all non-lead CPUs

Cluster	Core	Powerdown	Wakekup	Cache Flush
0	0	1.86	9.88	0.32
0	1	21.1	12.44	0.42
1	0	21.22	13.2	0.32
1	1	21.56	13.18	0.54

8.3.2.4. CPU_VERSION in parallel

CPU_VERSION latency (µs) in parallel on all cores

Cluster	Core	Latency
0	0	0.08
0	1	0.22
1	0	0.28
1	1	0.26

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