From 66ed26e06dfde0a7951161792cde5f06cf7b5af5 Mon Sep 17 00:00:00 2001
From: Michal Berger <michal.berger@intel.com>
Date: Tue, 31 Jan 2023 15:03:52 +0100
Subject: [PATCH] perf/pm: Discard < 0 readings coming from RAPL

Signed-off-by: Michal Berger <michal.berger@intel.com>
Change-Id: I5a4071441b6eed53553624c5ee587b7c91360eb5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/16633
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
---
 scripts/perf/pm/collect-bmc-pm | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/scripts/perf/pm/collect-bmc-pm b/scripts/perf/pm/collect-bmc-pm
index 45671eb12..6c8acdac1 100755
--- a/scripts/perf/pm/collect-bmc-pm
+++ b/scripts/perf/pm/collect-bmc-pm
@@ -349,6 +349,18 @@ get_cpu_socket_reading() {
 
 		# Convert to Watts - use bc since $interval can be an actual float
 		reading=$(calc "(${socket_uj[-1]} - ${socket_uj[-2]}) / 1000000 / $interval")
+		if ((reading < 0)); then
+			# Somehow this may happen, probably when the counter wraps over. Consider
+			# this as a faulty reading and don't include it since it may impact overall
+			# avg.
+			printf '(%s) CPU %s %s reading: error(%s) (interval: %ss)\n' \
+				"$ts" \
+				"$socket_name" \
+				"$socket_idx" \
+				"$reading" \
+				"$interval" >&2
+			return 0
+		fi
 		eval "_socket${_socket_idx}_readings+=($reading)"
 		power_readings["$socket_name-$socket_idx"]="_socket${_socket_idx}_readings[@]"