[DTrace-devel] [PATCH] Add a multi-CPU aggregation test

[eugene.loh at oracle.com]

From: Eugene Loh <eugene.loh at oracle.com>

A key characteristic of DTrace aggregations is that they are
gathered per CPU and then aggregated across CPUs.  Nevertheless,
the test suite uses only BEGIN and tick-n probes for aggregation
tests.  So, aggregation across CPUs is never really tested.

Add a test for the simplest aggregations with a probe that fires
across all CPUs.

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
---
 test/unittest/aggs/tst.multicpus.sh | 117 ++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100755 test/unittest/aggs/tst.multicpus.sh

diff --git a/test/unittest/aggs/tst.multicpus.sh b/test/unittest/aggs/tst.multicpus.sh
new file mode 100755
index 00000000..23b5c08d
--- /dev/null
+++ b/test/unittest/aggs/tst.multicpus.sh
@@ -0,0 +1,117 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+# Licensed under the Universal Permissive License v 1.0 as shown at
+# http://oss.oracle.com/licenses/upl.
+#
+
+dtrace=$1
+
+DIRNAME="$tmpdir/aggs_multicpus.$$.$RANDOM"
+mkdir -p $DIRNAME
+cd $DIRNAME
+
+#
+# Run a D script that fires on every CPU,
+# forcing DTrace to aggregate results over all CPUs.
+#
+
+$dtrace -qn '
+    profile-600ms
+    {
+        printf("cpu %d\n", cpu);
+        @xcnt = count();
+        @xavg = avg(10 * cpu + 3);
+        @xstd = stddev(20 * cpu + 8);
+        @xmin = min(30 * cpu - 10);
+        @xmax = max(40 * cpu - 15);
+        @xsum = sum(50 * cpu);
+    }
+    tick-900ms
+    {
+        exit(0)
+    }
+' > dtrace.out
+if [ $? -ne 0 ]; then
+    echo DTrace failed
+    cat dtrace.out
+    exit 1
+fi
+
+#
+# Examine the results.
+#
+
+awk '
+    BEGIN {
+        xcnt = xavg = xstm = xstd = xsum = 0;
+        xmin = +1000000000;
+        xmax = -1000000000;
+    }
+
+    # the first "cpu" lines provide the inputs to the aggregations
+    /^cpu [0-9]*$/ {
+
+        xcnt += 1;
+
+        x = 10 * $2 + 3;
+        xavg += x;
+
+        x = 20 * $2 + 8;
+        xstm += x;
+        xstd += x * x;
+
+        x = 30 * $2 - 10;
+        if (xmin > x) { xmin = x };
+
+        x = 40 * $2 - 15;
+        if (xmax < x) { xmax = x };
+
+        x = 50 * $2;
+        xsum += x;
+
+        next;
+    }
+
+    # the remaining lines are the aggregation results
+    {
+        # first we finish computing our estimates for avg and stddev
+        # (the other results require no further action)
+
+        xavg /= xcnt;
+
+        xstm /= xcnt;
+        xstd /= xcnt;
+        xstd -= xstm * xstm;
+        xstd = int(sqrt(xstd));
+
+        # now read the results and compare
+
+        getline; if ($1 != xcnt) { printf("ERROR: cnt, expect %d got %d\n", xcnt, $1) };
+        getline; if ($1 != xavg) { printf("ERROR: avg, expect %d got %d\n", xavg, $1) };
+        getline; if ($1 != xstd) { printf("ERROR: std, expect %d got %d\n", xstd, $1) };
+        getline; if ($1 != xmin) { printf("ERROR: min, expect %d got %d\n", xmin, $1) };
+        getline; if ($1 != xmax) { printf("ERROR: max, expect %d got %d\n", xmax, $1) };
+        getline; if ($1 != xsum) { printf("ERROR: sum, expect %d got %d\n", xsum, $1) };
+        printf("done\n");
+    }
+' dtrace.out > awk.out
+if [ $? -ne 0 ]; then
+    echo awk failed
+    cat dtrace.out
+    exit 1
+fi
+
+if grep -q ERROR awk.out ; then
+    echo ERROR found
+    echo "=================================================="
+    cat dtrace.out
+    echo "=================================================="
+    cat awk.out
+    echo "=================================================="
+    exit 1
+fi
+
+echo success
+exit 0
-- 
2.18.4