Usually, silent calls, or calls with one-way speech are caused by faulty DSP operation, not a lack of DSP resources.
You can test by selectively disabling your DSP daughterboards and placing test calls. If you can consistently repeat the problem when using a given DSP board, then many times rebooting that element (which forces it to reinitialize) will solve the problem. Otherwise, the DSP board will need to be replaced.
In direct answer to your original question, I suspect there are traffic measurements for those resources, but I'm not familiar with them.