Add SerializedAtomicRatio counter (#327)

Co-authored-by: Benjamin Welton <bewelton@amd.com>

source/lib/rocprofiler-sdk/counters/yaml/counter_defs.yaml

@@ -5761,3 +5761,10 @@ vL1dWriteToL2Latency:
     gfx90a:
       expression: TCP_TCC_WRITE_REQ_LATENCY_sum/(TCP_TCC_WRITE_REQ_sum+TCP_TCC_ATOMIC_WITHOUT_RET_REQ_sum)
   description: 'Unit: cycles'
+SerializedAtomicRatio:
+  architectures:
+    gfx950/gfx942/gfx941/gfx940/gfx90a:
+      expression: TCP_ATOMIC_TAGCONFLICT_STALL_CYCLES_sum/TCP_GATE_EN1_sum
+  description: Ratio of cycles spent waiting on serialized atomic accesses caused by contention 
+    (access to the same atomic) over total number of cycles spent on atomic operations. Values 
+    greater than 0.10 indicate contention is high and might be worth addressing.