perf(linux): AM64X: Update PREEMPT_RT perf numbers for 11.1

Update the real-time Linux latency numbers for SDK 11.1

Signed-off-by: Bryan Brattlof <[email protected]>

Author: bryanbrattlof

source/devices/AM64X/linux/RT_Linux_Performance_Guide.rst

@@ -58,14 +58,25 @@ Test commands used for running stress-ng and cyclictest together
    stress-ng --cpu-method=all -c 4 &
    cyclictest -m -Sp80 -D6h -h400 -i200 -M -q
 
-The latencies observed with this DK are summarized below:
+The following summarizes the latencies observed using the yocto based
+default SDK image:
+
+.. note::
+
+   A known issue in this SDK release is affecting this benchmark.
+   Using OP-TEE's PRNG drivers rather than the hardware accelerated TRNG
+   drivers restores the context switch latencies to the values you see
+   here.
+
+   More information on switching to the PRNG drivers can be found in the
+   Foundational Components section, here :ref:`building-optee-with-prng`
 
 .. csv-table::
    :header: "Latencies","CPU 0","CPU 1"
 
    "Minimum (usec)","6","6"
-   "Average (usec)","8","8"
-   "Maximum (usec)","77","105"
+   "Average (usec)","10","9"
+   "Maximum (usec)","77","52"
 
 .. image:: img/rt-cpu-method-all-latency-histogram.png
 
@@ -791,8 +802,8 @@ RP Message Inter-Processor Communication (IPC) Latency
 RP Message latency Performance
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-RP Message latency is the delay measured from sending a round trip echo message from 
-a Linux application to a remote processor and back. The following measurements use 
+RP Message latency is the delay measured from sending a round trip echo message from
+a Linux application to a remote processor and back. The following measurements use
 a RP message length of 1 byte and 490 bytes for comparison.
 
 The Linux user space application `rpmsg_char_benchmark <https://git.ti.com/cgit/rpmsg/ti-rpmsg-char/>`__ captures these latency values.