benchmarks: SetBytes takes bytes per operation

Where the code was multiplying bytes by number of operations, this
resulted in absurdly high throughput numbers.

Also, in `BenchmarkParse()`, don't run the `expfmt` case twice.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

model/textparse/promparse_test.go

@@ -367,7 +367,7 @@ func BenchmarkParse(b *testing.B) {
 			b.Run(parserName+"/no-decode-metric/"+fn, func(b *testing.B) {
 				total := 0
 
-				b.SetBytes(int64(len(buf) * (b.N / promtestdataSampleCount)))
+				b.SetBytes(int64(len(buf) / promtestdataSampleCount))
 				b.ReportAllocs()
 				b.ResetTimer()
 
@@ -395,7 +395,7 @@ func BenchmarkParse(b *testing.B) {
 			b.Run(parserName+"/decode-metric/"+fn, func(b *testing.B) {
 				total := 0
 
-				b.SetBytes(int64(len(buf) * (b.N / promtestdataSampleCount)))
+				b.SetBytes(int64(len(buf) / promtestdataSampleCount))
 				b.ReportAllocs()
 				b.ResetTimer()
 
@@ -428,7 +428,7 @@ func BenchmarkParse(b *testing.B) {
 				total := 0
 				res := make(labels.Labels, 0, 5)
 
-				b.SetBytes(int64(len(buf) * (b.N / promtestdataSampleCount)))
+				b.SetBytes(int64(len(buf) / promtestdataSampleCount))
 				b.ReportAllocs()
 				b.ResetTimer()
 
@@ -458,7 +458,10 @@ func BenchmarkParse(b *testing.B) {
 				_ = total
 			})
 			b.Run("expfmt-text/"+fn, func(b *testing.B) {
-				b.SetBytes(int64(len(buf) * (b.N / promtestdataSampleCount)))
+				if parserName != "prometheus" {
+					b.Skip()
+				}
+				b.SetBytes(int64(len(buf) / promtestdataSampleCount))
 				b.ReportAllocs()
 				b.ResetTimer()
 
@@ -507,7 +510,7 @@ func BenchmarkGzip(b *testing.B) {
 			k := b.N / promtestdataSampleCount
 
 			b.ReportAllocs()
-			b.SetBytes(int64(k) * int64(n))
+			b.SetBytes(int64(n) / promtestdataSampleCount)
 			b.ResetTimer()
 
 			total := 0

storage/buffer_test.go

@@ -176,7 +176,7 @@ func BenchmarkBufferedSeriesIterator(b *testing.B) {
 	// Simulate a 5 minute rate.
 	it := NewBufferIterator(newFakeSeriesIterator(int64(b.N), 30), 5*60)
 
-	b.SetBytes(int64(b.N * 16))
+	b.SetBytes(16)
 	b.ReportAllocs()
 	b.ResetTimer()
 

storage/memoized_iterator_test.go

@@ -75,7 +75,7 @@ func BenchmarkMemoizedSeriesIterator(b *testing.B) {
 	// Simulate a 5 minute rate.
 	it := NewMemoizedIterator(newFakeSeriesIterator(int64(b.N), 30), 5*60)
 
-	b.SetBytes(int64(b.N * 16))
+	b.SetBytes(16)
 	b.ReportAllocs()
 	b.ResetTimer()