From 6d29c101488f90ffdb08adcbda36cb7d06987ca7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lazar=20Cvetkovi=C4=87?= <l.cvetkovic.997@gmail.com>
Date: Mon, 25 Nov 2024 22:04:12 +0100
Subject: [PATCH] Fixing IAT for empty time slot
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Signed-off-by: Lazar Cvetković <l.cvetkovic.997@gmail.com>
---
 pkg/driver/trace_driver_test.go     |  4 +-
 pkg/generator/specification.go      | 23 +++++++++-
 pkg/generator/specification_test.go | 65 ++++++++++++++++++++++++++++-
 3 files changed, 87 insertions(+), 5 deletions(-)

diff --git a/pkg/driver/trace_driver_test.go b/pkg/driver/trace_driver_test.go
index 763f59702..1e98d1be9 100644
--- a/pkg/driver/trace_driver_test.go
+++ b/pkg/driver/trace_driver_test.go
@@ -346,7 +346,7 @@ func TestDriverCompletely(t *testing.T) {
 		{
 			testName:            "with_warmup",
 			withWarmup:          true,
-			expectedInvocations: 9,
+			expectedInvocations: 10,
 		},
 		{
 			testName:            "without_warmup_second_granularity",
@@ -420,7 +420,7 @@ func TestDriverCompletely(t *testing.T) {
 			}
 
 			expectedInvocations := test.expectedInvocations
-			if !(successfulInvocation >= expectedInvocations && failedInvocations == 0) {
+			if !(successfulInvocation == expectedInvocations && failedInvocations == 0) {
 				t.Error("Number of successful and failed invocations do not match.")
 			}
 		})
diff --git a/pkg/generator/specification.go b/pkg/generator/specification.go
index c97336c24..b29950b36 100644
--- a/pkg/generator/specification.go
+++ b/pkg/generator/specification.go
@@ -131,6 +131,14 @@ func (s *SpecificationGenerator) generateIATPerGranularity(minuteIndex int, numb
 	return iatResult, totalDuration
 }
 
+func getBlankTimeUnit(granularity common.TraceGranularity) float64 {
+	if granularity == common.MinuteGranularity {
+		return 60_000_000
+	} else {
+		return 1_000_000
+	}
+}
+
 // GenerateIAT generates IAT according to the given distribution. Number of minutes is the length of invocationsPerMinute array
 func (s *SpecificationGenerator) generateIAT(invocationsPerMinute []int, iatDistribution common.IatDistribution,
 	shiftIAT bool, granularity common.TraceGranularity) (common.IATArray, []int, common.ProbabilisticDuration) {
@@ -139,12 +147,23 @@ func (s *SpecificationGenerator) generateIAT(invocationsPerMinute []int, iatDist
 	var perMinuteCount []int
 	var nonScaledDuration []float64
 
+	accumulatedIdle := 0.0
+
 	numberOfMinutes := len(invocationsPerMinute)
 	for i := 0; i < numberOfMinutes; i++ {
 		minuteIAT, duration := s.generateIATPerGranularity(i, invocationsPerMinute[i], iatDistribution, shiftIAT, granularity)
+		if len(minuteIAT) == 0 {
+			accumulatedIdle += getBlankTimeUnit(granularity)
+			continue
+		} else if accumulatedIdle != 0 {
+			IAT = append(IAT, accumulatedIdle)
+			IAT = append(IAT, minuteIAT[1:]...)
+			accumulatedIdle = 0.0
+		} else {
+			IAT = append(IAT, minuteIAT...)
+		}
 
-		IAT = append(IAT, minuteIAT...)
-		perMinuteCount = append(perMinuteCount, len(minuteIAT))
+		perMinuteCount = append(perMinuteCount, len(minuteIAT)-1)
 		nonScaledDuration = append(nonScaledDuration, duration)
 	}
 
diff --git a/pkg/generator/specification_test.go b/pkg/generator/specification_test.go
index 72784619e..1def5122b 100644
--- a/pkg/generator/specification_test.go
+++ b/pkg/generator/specification_test.go
@@ -103,7 +103,7 @@ func TestSerialGenerateIAT(t *testing.T) {
 			testName:         "no_invocations_exponential_shift",
 			invocations:      []int{5},
 			iatDistribution:  common.Exponential,
-			shiftIAT:         false,
+			shiftIAT:         true,
 			granularity:      common.MinuteGranularity,
 			expectedPoints:   []float64{},
 			testDistribution: false,
@@ -223,6 +223,69 @@ func TestSerialGenerateIAT(t *testing.T) {
 			},
 			testDistribution: false,
 		},
+		{
+			testName:        "2min_5ipm_with_zero__equidistant",
+			invocations:     []int{0, 5},
+			iatDistribution: common.Equidistant,
+			shiftIAT:        false,
+			granularity:     common.MinuteGranularity,
+			expectedPoints: []float64{
+				60_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+			},
+			testDistribution: false,
+		},
+		{
+			testName:        "6min_5ipm_with_zero__equidistant",
+			invocations:     []int{0, 5, 0, 5, 0, 5},
+			iatDistribution: common.Equidistant,
+			shiftIAT:        false,
+			granularity:     common.MinuteGranularity,
+			expectedPoints: []float64{
+				60_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+				60_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+				60_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+				12_000_000,
+			},
+			testDistribution: false,
+		},
+		{
+			testName:        "2min_5ipm_with_zero_equidistant",
+			invocations:     []int{0, 1, 0, 1},
+			iatDistribution: common.Equidistant,
+			shiftIAT:        false,
+			granularity:     common.SecondGranularity,
+			expectedPoints: []float64{
+				1_000_000,
+				1_000_000,
+			},
+			testDistribution: false,
+		},
+		{
+			testName:        "five_empty_minutes",
+			invocations:     []int{0, 0, 0, 0, 0, 1},
+			iatDistribution: common.Equidistant,
+			shiftIAT:        false,
+			granularity:     common.MinuteGranularity,
+			expectedPoints: []float64{
+				300_000_000,
+			},
+			testDistribution: false,
+		},
 	}
 
 	var seed int64 = 123456789