Update mini-benchmark to use constant transactions

Mini-benchmark was using total time instead of total transactions
(events) to measure performance. This could give inconsistent results,
particulary when used to count CPU cycles. This changes the sysbench
command to use events x threads in each benchmark job, making the
benchmark more informative.

When `perf` [1] is available and enabled, mini-benchmark will measure how
many CPU cycles are required to do a fixed amount of work/queries. If
`perf` is unavailable, mini-benchmark will measure the peak queries per
second (QPS) during the execution of this work, regardless of the
duration.

[1] https://perf.wiki.kernel.org

support-files/mini-benchmark.sh

@@ -16,8 +16,8 @@ display_help() {
   echo "                     representing the threads to run."
   echo "                     example: --threads \"1 32 64 128\""
   echo "                     default: \"1 2 4 8 16\""
-  echo "  --duration INTEGER duration of each thread run in seconds"
+  echo "  --events INTEGER   number of transactions per thread to execute for each test"
-  echo "                     default: 60"
+  echo "                     default: 10000"
   echo "  --workload STRING  sysbench workload to execute"
   echo "                     default: oltp_read_write"
   echo "  --log              logs the mini-benchmark stdout/stderr into the"
@@ -34,7 +34,7 @@ display_help() {
 # Default parameters
 BENCHMARK_NAME='mini-benchmark'
 THREADS='1 2 4 8 16'
-DURATION=60
+EVENTS=10000
 WORKLOAD='oltp_read_write'
 
 while :
@@ -59,9 +59,9 @@ do
       THREADS=$1
       shift
       ;;
-    --duration)
+    --events)
       shift
-      DURATION=$1
+      EVENTS=$1
       shift
       ;;
     --workload)
@@ -102,6 +102,7 @@ done
 TIMESTAMP="$(date -Iseconds)"
 mkdir "$BENCHMARK_NAME-$TIMESTAMP"
 cd "$BENCHMARK_NAME-$TIMESTAMP" || exit 1
+FAIL=false
 
 (
 # Check that the dependencies of this script are available
@@ -233,7 +234,7 @@ do
   # Prepend command with perf if defined
   # Output stderr to stdout as perf outputs everything in stderr
   # shellcheck disable=SC2086
-  $PERF_COMMAND $TASKSET_SYSBENCH sysbench "$WORKLOAD" run --threads=$t --time=$DURATION --report-interval=10 2>&1 | tee sysbench-run-$t.log
+  $PERF_COMMAND $TASKSET_SYSBENCH sysbench "$WORKLOAD" run --threads=$t --events=$(($EVENTS * $t)) --report-interval=10 2>&1 | tee sysbench-run-$t.log
 done
 
 sysbench "$WORKLOAD" cleanup --tables=20 | tee sysbench-cleanup.log
@@ -256,20 +257,21 @@ then
 
   if [ -z "$CPU_CYCLE_LIMIT" ]
   then 
-     # 04-04-2024: We found this to be an appropriate default limit after running a few benchmarks
+     # 2024-09-10: We found this to be an appropriate default limit after running a few benchmarks
      # Configure the limit with --cpu-limit if needed
-    CPU_CYCLE_LIMIT=750
+    CPU_CYCLE_LIMIT=125
   fi
   CPU_CYCLE_LIMIT_LONG="${CPU_CYCLE_LIMIT}000000000"
 
   # Final verdict based on cpu cycle count
   RESULT="$(grep -h -e cycles sysbench-run-*.log | sort -k 1 | awk '{s+=$1}END{print s}')"
+  echo "CPU cycle count: ${RESULT}"
   if [ "$RESULT" -gt "$CPU_CYCLE_LIMIT_LONG" ]
   then
     echo # Newline improves readability
     echo "Benchmark exceeded the allowed limit of ${CPU_CYCLE_LIMIT} billion CPU cycles"
     echo "Performance most likely regressed!"
-    exit 1
+    FAIL=true
   fi
 fi
 
@@ -302,12 +304,13 @@ case $RESULT in
     then
       echo # Newline improves readability
       echo "Benchmark did not reach 13000+ qps, performance most likely regressed!"
-      exit 1
+      FAIL=true
     else
-      echo "Banchmark passed with $RESULT queries per second as peak value"
+      echo "Benchmark passed with $RESULT queries per second as peak value"
     fi
     ;;
 esac
+if $FAIL ; then exit 1 ; fi
 # Record the output into the log file, if requested
 ) 2>&1 | ($LOG && tee "$BENCHMARK_NAME"-"$TIMESTAMP".log)
 exit ${PIPESTATUS[0]} # Propagate errors in the sub-shell