generate-pmu.sh: CPU perf event code generator

Add a script that can automatically generate Lua definitions for the
hundreds of specific Performance Monitoring Unit events available in
each individual Intel CPU.

src/scripts/generate-pmu.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+
+# Script to generate Lua definitions of CPU Performance Monitoring
+# Unit (PMU) events. These definitions can then be used as arguments
+# to the Linux perf_event_open(2) system call to monitor detailed
+# performance counters.
+#
+# Currently supports Intel CPUs and automatically downloads the latest
+# definitions from an Intel website.
+#
+# This script is doing similar work to parts of Intel pmu-tools.
+
+if [ ! -d download.01.org ]; then
+    echo "Downloading Intel spec files" >&2
+    wget -A csv,tsv,json -nv -r --no-parent https://download.01.org/perfmon/
+fi
+cd download.01.org/perfmon
+
+echo "-- AUTOMATICALLY GENERATED FILE"
+echo "-- Date: $(date)"
+echo "-- Cmd:  $0 $@"
+echo
+echo "return"
+echo " {"
+
+tail -n +2 mapfile.csv | \
+ while IFS=, read cpu version path type; do
+    echo "  {\"$cpu\", \"$version\", \"$type\","
+    echo "   {"
+    tsv=$(echo $path | sed -e 's;^/;;' -e 's;json$;tsv;')
+    echo "    -- source: $tsv"
+    # Note: The intention is for values to be in the raw format
+    # expected by Linux perf_event_open(2). However, the encoding in
+    # this script may be incorrect for one or more event types.
+    #
+    # One reference is "perf list --help" section "RAW HARDWARE EVENT
+    # DESCRIPTOR". This does not seem to say how to encode the offcore
+    # events where two event codes are given in the spec file. More
+    # research needed to understand what information this script needs
+    # to include and how that should be passed to perf_event_open(2).
+    grep -v '^ *#' $tsv | tail -n +2 | \
+    case $type in
+        core)
+            awk -F '\t' \
+                '{ printf("    [\"%s\"] = 0x%02x%02x,\n", tolower($3), $2, $1); }'
+            ;;
+        uncore)
+            awk -F '\t' \
+                '{ printf("    [\"%s\"] = 0x%02x%02x,\n", tolower($4), $3, $2); }'
+            ;;
+        offcore)
+            echo "    -- [skipping offcore events. How are they encoded?]"
+            ;;
+    esac
+    echo "   },"
+    echo "  },"
+ done
+echo " }"
+exit