Enable mini-benchmark to run with perf

The mini-benchmark.sh script failed to run in the latest Fedora
distributions in GitLab CI. Executing the benchmark inside a Docker
container had failed because the check for `perf` was done in a way that
caused the benchmark to exit because of the `set -e` option. Test and
skip `perf` to allowing the remaining benchmark activities to proceed.

This check was added in acb6684 but inadvertantly reverted in 42a1f94.

Logic was corrected to only run perf when the flag is enabled, and to
prevent perf stat and perf record from being simultaneously enabled.

Set -ex is also added to enable easier identification of mini-benchmark
issues in the future.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

.gitlab-ci.yml

@@ -510,9 +510,9 @@ mini-benchmark:
     - |
       mariadb --skip-column-names -e "SELECT @@version, @@version_comment" | tee /tmp/version
       grep $MARIADB_MAJOR_VERSION /tmp/version || echo "MariaDB didn't install properly"
-    - yum install -y sysbench procps-ng perf util-linux || yum install -y https://kojipkgs.fedoraproject.org//packages/luajit/2.0.4/3.el7/x86_64/luajit-2.0.4-3.el7.x86_64.rpm https://kojipkgs.fedoraproject.org//packages/sysbench/1.0.17/2.el7/x86_64/sysbench-1.0.17-2.el7.x86_64.rpm https://kojipkgs.fedoraproject.org//packages/ck/0.5.2/2.el7/x86_64/ck-0.5.2-2.el7.x86_64.rpm
+    - yum install -y sysbench procps-ng perf flamegraph flamegraph-stackcollapse-perf util-linux dnf-utils
     - /usr/share/mysql/mini-benchmark
-    - cp -av */sysbench-run-*.log */metrics.txt ..  # Move files one level down so they can be saved as artifacts
+    - cp -av */sysbench-run-*.log */metrics.txt .  # Move files one level down so they can be saved as artifacts
   artifacts:
     when: always
     paths:

support-files/mini-benchmark.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 # Abort on errors
-set -e
+set -ex
 
 display_help() {
   echo "Usage: $(basename "$0") [-h] [--perf] [--perf-flamegraph]"
@@ -121,6 +121,12 @@ then
   exit 1
 fi
 
+if [ "$PERF" == true ] && [ "$PERF_RECORD" == true ]
+then
+  echo "ERROR: Cannot select both --perf and --perf-flamegraph options simultaneously. Please choose one or the other."
+  exit 1
+fi
+
 if [ "$PERF" == true ] || [ "$PERF_RECORD" == true ]
 then
   if [ ! -e /usr/bin/perf ]
@@ -158,28 +164,26 @@ then
   # shellcheck disable=SC2046
   debuginfo-install -y mariadb-server $(cat mariadbd-dependencies.txt)
 
-  perf record echo "testing perf" > /dev/null 2>&1
-  if [ $? -ne 0 ]
+  if ! (perf record echo "testing perf") > /dev/null 2>&1
   then
     echo "perf does not have permission to run on this system. Skipping."
-    PERF=""
+    PERF_COMMAND=""
   else
     echo "Using 'perf' to record performance counters in perf.data files"
-    PERF="perf record -g --freq=99 --output=perf.data --timestamp-filename --pid=$MARIADB_SERVER_PID --"
+    PERF_COMMAND="perf record -g --freq=99 --output=perf.data --timestamp-filename --pid=$MARIADB_SERVER_PID --"
   fi
 
-elif [ -e /usr/bin/perf ]
+elif [ "$PERF" == true ]
 then
   # If flamegraphs were not requested, log normal perf counters if possible
 
-  perf stat echo "testing perf" > /dev/null 2>&1
-  if [ $? -ne 0 ]
+  if ! (perf stat echo "testing perf") > /dev/null 2>&1
   then
     echo "perf does not have permission to run on this system. Skipping."
-    PERF=""
+    PERF_COMMAND=""
   else
     echo "Using 'perf' to log basic performance counters for benchmark"
-    PERF="perf stat -p $MARIADB_SERVER_PID --"
+    PERF_COMMAND="perf stat -p $MARIADB_SERVER_PID --"
   fi
 fi
 
@@ -222,7 +226,7 @@ do
   # Prepend command with perf if defined
   # Output stderr to stdout as perf outputs everything in stderr
   # shellcheck disable=SC2086
-  $PERF $TASKSET_SYSBENCH sysbench "$WORKLOAD" run --threads=$t --time=$DURATION --report-interval=10 2>&1 | tee sysbench-run-$t.log
+  $PERF_COMMAND $TASKSET_SYSBENCH sysbench "$WORKLOAD" run --threads=$t --time=$DURATION --report-interval=10 2>&1 | tee sysbench-run-$t.log
 done
 
 sysbench "$WORKLOAD" cleanup --tables=20 | tee sysbench-cleanup.log