From 5e23a9231476e9a60251ed3823b6e9c227e38f59 Mon Sep 17 00:00:00 2001
From: Sam Fredrickson <samfredrickson@gmail.com>
Date: Wed, 1 Mar 2023 19:31:36 -0800
Subject: [PATCH] Add high contention benchmark.

---
 lib_test.go    | 36 +++++++++++++++++++++++++++++
 mq/lib_test.go | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+)

diff --git a/lib_test.go b/lib_test.go
index e636b20..5dd7c46 100644
--- a/lib_test.go
+++ b/lib_test.go
@@ -2,6 +2,7 @@ package priorityq_test
 
 import (
 	"math/rand"
+	"runtime"
 	"sync"
 	"testing"
 
@@ -177,3 +178,38 @@ func BenchmarkConcSendRecv(b *testing.B) {
 	close(start)
 	wg.Wait()
 }
+
+func BenchmarkHighContention(b *testing.B) {
+	q := priorityq.Make[int, int](b.N)
+	var wg sync.WaitGroup
+	start := make(chan struct{})
+	done := make(chan struct{})
+	numProducers := runtime.NumCPU()
+	sendsPerProducer := b.N / numProducers
+	wg.Add(numProducers)
+	for i := 0; i < numProducers; i++ {
+		go func() {
+			ps := make([]int, sendsPerProducer)
+			for i := 0; i < sendsPerProducer; i++ {
+				ps[i] = rand.Int()
+			}
+			<-start
+			for i := 0; i < sendsPerProducer; i++ {
+				q.Send(ps[i], 1)
+			}
+			wg.Done()
+		}()
+	}
+	go func() {
+		ok := true
+		for ok {
+			_, _, ok = q.Recv()
+		}
+		close(done)
+	}()
+	b.ResetTimer()
+	close(start)
+	wg.Wait()
+	q.Close()
+	<-done
+}
diff --git a/mq/lib_test.go b/mq/lib_test.go
index a887a73..54d0457 100644
--- a/mq/lib_test.go
+++ b/mq/lib_test.go
@@ -2,6 +2,7 @@ package mq_test
 
 import (
 	"math/rand"
+	"runtime"
 	"sync"
 	"testing"
 
@@ -226,3 +227,64 @@ func BenchmarkConcSendRecvChan(b *testing.B) {
 	close(start)
 	wg.Wait()
 }
+
+func BenchmarkHighContention(b *testing.B) {
+	q := mq.Make[int](b.N)
+	var wg sync.WaitGroup
+	start := make(chan struct{})
+	done := make(chan struct{})
+	numProducers := runtime.NumCPU()
+	sendsPerProducer := b.N / numProducers
+	wg.Add(numProducers)
+	for i := 0; i < numProducers; i++ {
+		go func() {
+			<-start
+			for i := 0; i < sendsPerProducer; i++ {
+				q.Send(1)
+			}
+			wg.Done()
+		}()
+	}
+	go func() {
+		ok := true
+		for ok {
+			_, ok = q.Recv()
+		}
+		close(done)
+	}()
+	b.ResetTimer()
+	close(start)
+	wg.Wait()
+	q.Close()
+	<-done
+}
+
+func BenchmarkHighContentionChan(b *testing.B) {
+	c := make(chan int, b.N)
+	var wg sync.WaitGroup
+	start := make(chan struct{})
+	done := make(chan struct{})
+	numProducers := runtime.NumCPU()
+	sendsPerProducer := b.N / numProducers
+	wg.Add(numProducers)
+	for i := 0; i < numProducers; i++ {
+		go func() {
+			<-start
+			for i := 0; i < sendsPerProducer; i++ {
+				c <- 1
+			}
+			wg.Done()
+		}()
+	}
+	go func() {
+		for n := range c {
+			_ = n
+		}
+		close(done)
+	}()
+	b.ResetTimer()
+	close(start)
+	wg.Wait()
+	close(c)
+	<-done
+}