Looking at the task output I'm seeing some errors & warnings and don't know how to address them.

<search_application> milkyway_separation 1.46 Windows x86 double OpenCL </search_application>
Reading preferences ended prematurely
BOINC GPU type suggests using OpenCL vendor 'Advanced Micro Devices, Inc.'
Error loading Lua script 'astronomy_parameters.txt': [string "number_parameters: 4..."]:1: '<name>' expected near '4'
Switching to Parameter File 'astronomy_parameters.txt'
<number_WUs> 4 </number_WUs>
<number_params_per_WU> 26 </number_params_per_WU>

and

C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:183:72: warning: unknown attribute 'max_constant_size' ignored
__constant real* _ap_consts __attribute__((max_constant_size(18 * sizeof(real)))),
^
C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:185:62: warning: unknown attribute 'max_constant_size' ignored
__constant SC* sc __attribute__((max_constant_size(NSTREAM * sizeof(SC)))),
^
C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:186:67: warning: unknown attribute 'max_constant_size' ignored
__constant real* sg_dx __attribute__((max_constant_size(256 * sizeof(real)))),
^
3 warnings generated.

WU's for both milkway & milkyway_nbody are completing without error.

Couple of notes:

BOINC is installed to my E: drive, not C:

Intel(R) Xeon(R) CPU E5-2697 v2 @ 2.70GHz [Family 6 Model 62 Stepping 4]
(48 processors)
AMD Radeon Vega Frontier Edition (16368MB) OpenCL: 2.0

App_Config is as follows:

<app_config>
<app>
<name>milkyway</name>
<max_concurrent>4</max_concurrent>
<gpu_versions>
<gpu_usage>0.50</gpu_usage>
<cpu_usage>0.50</cpu_usage>
</gpu_versions>
</app>
<app_version>
<app_name>milkyway_nbody</app_name>
<plan_class>mt</plan_class>
<avg_ncpus>4.0</avg_ncpus>
<cmdline>--nthreads4.0</cmdline>
</app_version>
</app_config>

Also, looking in the project directory I no longer see the GPU configuration xml file for milkyway_1.46_windows_x86_64__opencl_ati_101. Is this not supported?

Looking at the task output I'm seeing some errors & warnings and don't know how to address them.

<search_application> milkyway_separation 1.46 Windows x86 double OpenCL </search_application>
Reading preferences ended prematurely
BOINC GPU type suggests using OpenCL vendor 'Advanced Micro Devices, Inc.'
Error loading Lua script 'astronomy_parameters.txt': [string "number_parameters: 4..."]:1: '<name>' expected near '4'
Switching to Parameter File 'astronomy_parameters.txt'
<number_WUs> 4 </number_WUs>
<number_params_per_WU> 26 </number_params_per_WU>

This error is in all my valid work units visible.

You can ignore it.

C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:183:72: warning: unknown attribute 'max_constant_size' ignored
__constant real* _ap_consts __attribute__((max_constant_size(18 * sizeof(real)))),
^
C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:185:62: warning: unknown attribute 'max_constant_size' ignored
__constant SC* sc __attribute__((max_constant_size(NSTREAM * sizeof(SC)))),
^
C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:186:67: warning: unknown attribute 'max_constant_size' ignored
__constant real* sg_dx __attribute__((max_constant_size(256 * sizeof(real)))),
^
3 warnings generated.

I've seen the warnings before too, asked about them and told they can be ignored.

<cmdline>--nthreads4.0</cmdline>

Is this syntax giving you 4 threads?
Always seen this as integer input:
<cmdline>--nthreads 4</cmdline>

Also, looking in the project directory I no longer see the GPU configuration xml file for milkyway_1.46_windows_x86_64__opencl_ati_101. Is this not supported?

This, I do not know the answer to and would like to see the response.

Thank you for responding.

Would prefer to correct rather than ignore but if the errors are harmless, and they do seem to be, I suppose just ignore it.

Is this syntax giving you 4 threads?
Always seen this as integer input:
<cmdline>--nthreads 4</cmdline>

Made the change but don't know how to confirm the thread count. Where would I look?

Also, looking at my client I have 37 WU's of nbody simulations running along with 2 GPU separation units, each at 0.5 CPU.

I have 24 physical cores and 24 virtual cores and am allowing 80% of the cores to be used. Would appear that each WU is running on a core?

I thought the app_config would assign multiple cores to a single task? Perhaps speeding up the computations?

Looking at the task output I'm seeing some errors & warnings and don't know how to address them.

<search_application> milkyway_separation 1.46 Windows x86 double OpenCL </search_application>
Reading preferences ended prematurely
BOINC GPU type suggests using OpenCL vendor 'Advanced Micro Devices, Inc.'
Error loading Lua script 'astronomy_parameters.txt': [string "number_parameters: 4..."]:1: '<name>' expected near '4'
Switching to Parameter File 'astronomy_parameters.txt'
<number_WUs> 4 </number_WUs>
<number_params_per_WU> 26 </number_params_per_WU>

This error is in all my valid work units visible.

You can ignore it.

C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:183:72: warning: unknown attribute 'max_constant_size' ignored
__constant real* _ap_consts __attribute__((max_constant_size(18 * sizeof(real)))),
^
C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:185:62: warning: unknown attribute 'max_constant_size' ignored
__constant SC* sc __attribute__((max_constant_size(NSTREAM * sizeof(SC)))),
^
C:\Users\jnedd\AppData\Local\Temp\\OCL8644T1.cl:186:67: warning: unknown attribute 'max_constant_size' ignored
__constant real* sg_dx __attribute__((max_constant_size(256 * sizeof(real)))),
^
3 warnings generated.

I've seen the warnings before too, asked about them and told they can be ignored.

<cmdline>--nthreads4.0</cmdline>

Is this syntax giving you 4 threads?
Always seen this as integer input:
<cmdline>--nthreads 4</cmdline>

Also, looking in the project directory I no longer see the GPU configuration xml file for milkyway_1.46_windows_x86_64__opencl_ati_101. Is this not supported?

This, I do not know the answer to and would like to see the response.

This is how the app_config.xml file is syntaxed:

<app_config>
[<app>
<name>Application_Name</name>
<max_concurrent>1</max_concurrent>
[<report_results_immediately/>]
[<fraction_done_exact/>]
<gpu_versions>
<gpu_usage>.5</gpu_usage>
<cpu_usage>.4</cpu_usage>
</gpu_versions>
</app>]
...
[<app_version>
<app_name>Application_Name</app_name>
[<plan_class>mt</plan_class>]
[<avg_ncpus>x</avg_ncpus>]
[<ngpus>x</ngpus>]
[<cmdline>--nthreads 7</cmdline>]
</app_version>]
...
[<project_max_concurrent>N</project_max_concurrent>]
[<report_results_immediately/>]
</app_config>

I have no clue what these lines do:

<cmdline>--nthreads4.0</cmdline>

https://boinc.berkeley.edu/wiki/Client_configuration

AND it may be the NEXT set of wu's you get that it applies to not the current set, some projects do it right away while others wait until you get a new set of wu's. To try it out suspend MW, click inside the Boinc Manager to read the config files, then click to resume crunching MW.

Toggled this line, <project_max_concurrent>x</project_max_concurrent>, about and changes in value are reflected in total # WU's running. This seems most useful as it limits the total number of WU's running.

<avg_ncpus>x</avg_ncpus> - the number of CPU instances used by the app version.

I'm thinking the CPU instances the same as cores. I have 2 12-core CPU's
If I'm running 6 WU's and set x to 6, does that mean, on average, 1 CPU (core) would be available per WU?
And if I set it to 12, on average, 2 CPU (core) would be available per WU?

<ngpus>x</ngpus> - the number of GPU instances used by the app

If nbody is a CPU task then what is the purpose to adding this line in the app_config file?

<cmdline>--nthreads x</cmdline>

What I could find on the BOINC message board.

avg_ncpus tells BOINC how many threads to reserve for the job scheduling
cmdline tells BOINC how many threads the application may use at maximum
Milkway Nbody tasks can run on any number of threads that you care to set for them, but do keep the numbers you use for avg_ncpus and nthreads equal.

Made the change but don't know how to confirm the thread count. Where would I look?

I use a task manager, like Process Hacker, and look at the CPU usage of the WU.

Since you have 24 cores, a single threaded process will use 1/24 ~= 4.1 % under CPU usage.

4 threads should be using ~16.6%. You can use the properties feature of many task managers to look at the internal threads.
You should see 4 identically named child processes taking up 4.1% CPU and have much CPU cycles of usage.

I thought the app_config would assign multiple cores to a single task? Perhaps speeding up the computations?

BOINC doesn't have an AI to perform that manipulation. On some projects you'll just have to choose properly in project settings, some projects default to multi-thread (YAFU, XANSONs, etc.), while some projects are capable of multi-threading but it's a hidden feature you need to use app_config to enable.
Keep an eye out for optimized applications that you can optionally add also. SETI has one which has some partial multi threading.

<ngpus>x</ngpus> - the number of GPU instances used by the app

If nbody is a CPU task then what is the purpose to adding this line in the app_config file?

Milkyway has GPU WU's and the app_config.xml covers all WU's under Milkyway so if/when you run some GPU WU, it'll be useful.

avg_ncpus tells BOINC how many threads to reserve for the job scheduling

This is number of CPU's you want each WU to attempt to use (where it might use less in certain phases). It's a per WU variable.

cmdline tells BOINC how many threads the application may use at maximum
Milkway Nbody tasks can run on any number of threads that you care to set for them, but do keep the numbers you use for avg_ncpus and nthreads equal.

What you had built in your first post was fine, just make sure the cmdline is '--nthreads 4'.

Lastly, changes to app_config.xml or cc_config.xml don't take effect until you go to the advanced menu on BOINC Manager and select options -> read config files and you'll see the WU's readjust to the new settings in a few seconds.
BOINC Manager has a bug that it won't show the changes in the work unit descriptions even though the changes take effect.
So, it's usually best to shut down BOINC and restart it unless (and there are some) a project's WU doesn't make proper save points and will lose hours of work or some rare WU's will die upon suspension/restart (not naming names, but one I know of using Oracle VM WU's).

To make an app_info.xml (for anonymous platforms) change take effect, you must restart BOINC.

This info will help you out on all projects.
Good you are asking.

Thanks so much for explaining. I appreciate the time you took to respond in detail and the knowledge you passed on.