Update Arm NN FAQ with intermittent error information

Signed-off-by: Nikhil Raj <nikhil.raj@arm.com>
Change-Id: I4f2e5c975fe4f273e80c065aa57861d0d78f0ea0

1 files changed, 21 insertions, 7 deletions

diff --git a/docs/FAQ.md b/docs/FAQ.md
index 4e8e177068..f80c1ea22b 100644
--- a/docs/FAQ.md
+++ b/docs/FAQ.md
@@ -1,7 +1,7 @@
 Frequently asked questions
 ==========================
 
-These are issues that have been commonly seen when using ArmNN.
+These are issues that have been commonly seen when using Arm NN.
 
 Note: The 21.08 release of Arm NN removes Boost library dependency. You are not required to install boost library with 21.08 and newer releases.
 
@@ -12,7 +12,7 @@ Some users have encountered difficulties when attempting to build armnn and Comp
 
 error: ‘HARD_SWISH’ is not a member of ‘AclActivationFunction {aka arm_compute::ActivationLayerInfo::ActivationFunction}’
 
-The most common reason for these errors are a mismatch between armnn and clframework revisions. For any version of ArmNN the coresponding version of ComputeLibrary is detailed in scripts/get_compute_library.sh as DEFAULT_CLFRAMEWORKREVISION
+The most common reason for these errors are a mismatch between armnn and clframework revisions. For any version of Arm NN the coresponding version of ComputeLibrary is detailed in scripts/get_compute_library.sh as DEFAULT_CLFRAMEWORKREVISION
 
 On *nix like systems running this script will checkout ComputeLibrary, with the current default SHA, into ../../clframework/ relative to the location of the script.
 
@@ -23,10 +23,10 @@ In some error scenarios of calls to armnn::Optimize a null pointer may be return
 
 If you encounter this problem and are able to isolate it consider contributing a solution.
 
-Adding or removing -Dxxx options when building ArmNN does not always work.
+Adding or removing -Dxxx options when building Arm NN does not always work.
 ---------------------------------------------------------
 
-ArmNN uses CMake for build configuration. CMake uses a cumulative cache of user options. That is, setting a value once on a cmake command line will be persisted until either you explicitly change the value or delete the cache. To delete the cache in ArmNN you must delete the build directory.
+Arm NN uses CMake for build configuration. CMake uses a cumulative cache of user options. That is, setting a value once on a cmake command line will be persisted until either you explicitly change the value or delete the cache. To delete the cache in Arm NN you must delete the build directory.
 
 Many DynamicBackendTests fail with "Base path for shared objects does not exist".
 ---------------------------------------------------------
@@ -38,16 +38,16 @@ Some combinations of GCC cross compiler and pthread runtime in an armv7 environm
 
 UnitTests fail on Max OS-X with errors in boost::program_options
 ---------------------------------------------------------
-When executing ArmNN UnitTests built in an OS-X environment, runtime errors occur around boost::program_options. When compiling boost the "b2" tool appears to have a bug where it defaults to using the native ranlib even when the correct tool is specified in the user_config.jam.
+When executing Arm NN UnitTests built in an OS-X environment, runtime errors occur around boost::program_options. When compiling boost the "b2" tool appears to have a bug where it defaults to using the native ranlib even when the correct tool is specified in the user_config.jam.
 
 To validate that this issue is occurring inspect the boost build log looking for warnings like:
 warning: ranlib: warning for library: libboost_atomic.a the table of contents is empty (no object file members in the library define global symbols)
 
 This problem has previously been reported to the boostorg GitHub project. The solution is to manually execute the correct ranlib on each static library. https://github.com/boostorg/build/issues/160
 
-ArmNN fails to build on Ubuntu 20.04
+Arm NN fails to build on Ubuntu 20.04
 ---------------------------------------------------------
-The compiler version update on Ubuntu 20.04 resulted in build errors in Flat buffers 1.10.0. Update to Flatbuffers 1.12.0 to resolve this problem. In addition when building flatbuffers specify -fPIC CXX flag to allow the libraries to be used in our shared objects. Without this the the ArmNN build can fail with libflatbuffers.a(util.cpp.o): relocation R_X86_64_PC32 against symbol `_ZN11flatbuffers9DirExistsEPKc' can not be used when making a shared object; recompile with -fPIC
+The compiler version update on Ubuntu 20.04 resulted in build errors in Flat buffers 1.10.0. Update to Flatbuffers 1.12.0 to resolve this problem. In addition when building flatbuffers specify -fPIC CXX flag to allow the libraries to be used in our shared objects. Without this the the Arm NN build can fail with libflatbuffers.a(util.cpp.o): relocation R_X86_64_PC32 against symbol `_ZN11flatbuffers9DirExistsEPKc' can not be used when making a shared object; recompile with -fPIC
 
 Tensorflow Lite benchmarking tool fails with segmentation fault when using the Arm NN delegate.
 ---------------------------------------------------------
@@ -62,3 +62,17 @@ This example is for:
 ~~~
 LD_LIBRARY_PATH=/vendor/lib64/egl:/vendor/lib/egl/:. ./android_aarch64_benchmark_model --num_threads=4 --graph=/data/local/tmp/mobilenet_v2_1.0_224_quantized_1_default_1.tflite --external_delegate_path="libarmnnDelegate.so" --external_delegate_options="backends:GpuAcc"
 ~~~
+
+Arm NN fails to build intermittently on 18.04 Ubuntu
+---------------------------------------------------------
+Building Arm NN fails intermittently with error:
+
+c++: internal compiler error: Killed (program cc1plus)
+
+This errors appears to be related to the number of cmake jobs used to build Arm NN.Try limiting the jobs to 2 by modifying the make to:
+
+make -j2
+
+Arm NN UnitTests fails intermittently with segmentation fault on aarch64.
+----------------------------------------------------------
+The DefaultAsyncExeuteWithThreads test seems to be throwing intermittent segmentation fault while running Arm NN Unittest in aarch64 architecture. This test will pass if you run the Unittest again.