Use 1st workload cpu as the cpu main thread

cpu main thread must be an isolated cpu, otherwise it may spike
due to load pressure on the hk cores.

oslat-client

@@ -104,8 +104,13 @@ echo -e "${CMD_OUTPUT}"
 HK_CPUS=$(echo -e "${CMD_OUTPUT}" | grep "final cpus:" | awk '{ print $3 }')
 echo "HK_CPUS: ${HK_CPUS}"
 
-# get the first CPU from HK_CPUS to use as the oslat main thread
-cpu_main_thread=$(echo ${HK_CPUS} | awk -F, '{ print $1 }')
+# get the first CPU from WORKLOAD_CPUS to use as the oslat main thread
+cpu_main_thread=$(echo ${WORKLOAD_CPUS} | awk -F, '{ print $1 }')
+echo "cpu-main-thread: ${cpu_main_thread}"
+
+# LATENCY_CPUS are the WORKLOAD_CPUS less the cpu main thread
+LATENCY_CPUS=$(echo ${WORKLOAD_CPUS} | cut -d ',' -f2-)
+echo "LATENCY_CPUS: ${LATENCY_CPUS}"
 
 echo
 cmd="oslat --help"
@@ -130,7 +135,7 @@ if [ $? != 0 ]; then
     exit_error "${output}"
 fi
 
-cmd="taskset -c ${HK_CPUS},${WORKLOAD_CPUS} oslat --duration ${duration} ${rtprio_opt} --cpu-list ${WORKLOAD_CPUS} --cpu-main-thread ${cpu_main_thread} ${trace_args}"
+cmd="taskset -c ${WORKLOAD_CPUS} oslat --duration ${duration} ${rtprio_opt} --cpu-list ${LATENCY_CPUS} --cpu-main-thread ${cpu_main_thread} ${trace_args}"
 echo "About to run: $cmd"
 date +%s.%N >begin.txt
 $cmd >oslat-bin-stderrout.txt 2>&1