From f4cd2a71208fa7d50392bd5a00f15981d0a5d6df Mon Sep 17 00:00:00 2001
From: greatroar <@>
Date: Tue, 26 May 2020 13:22:38 +0200
Subject: [PATCH] Make backend benchmarks fairer by removing checks
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Checking whether the right data is returned takes up half the time in
some benchmarks. Results for local backend benchmarks on linux/amd64:

name                                      old time/op    new time/op    delta
Backend/BenchmarkLoadFile-8                 4.89ms ± 0%    2.72ms ± 1%   -44.26%  (p=0.008 n=5+5)
Backend/BenchmarkLoadPartialFile-8           936µs ± 6%     439µs ±15%   -53.07%  (p=0.008 n=5+5)
Backend/BenchmarkLoadPartialFileOffset-8     940µs ± 1%     456µs ±10%   -51.50%  (p=0.008 n=5+5)
Backend/BenchmarkSave-8                     23.9ms ±14%    24.8ms ±41%      ~     (p=0.690 n=5+5)

name                                      old speed      new speed      delta
Backend/BenchmarkLoadFile-8               3.43GB/s ± 0%  6.16GB/s ± 1%   +79.40%  (p=0.008 n=5+5)
Backend/BenchmarkLoadPartialFile-8        4.48GB/s ± 6%  9.63GB/s ±14%  +114.78%  (p=0.008 n=5+5)
Backend/BenchmarkLoadPartialFileOffset-8  4.46GB/s ± 1%  9.22GB/s ±10%  +106.74%  (p=0.008 n=5+5)
Backend/BenchmarkSave-8                    706MB/s ±13%   698MB/s ±31%      ~     (p=0.690 n=5+5)
---
 internal/backend/test/benchmarks.go | 43 ++++++++++++++---------------
 1 file changed, 21 insertions(+), 22 deletions(-)

diff --git a/internal/backend/test/benchmarks.go b/internal/backend/test/benchmarks.go
index 302768f2e..94c3b6c9e 100644
--- a/internal/backend/test/benchmarks.go
+++ b/internal/backend/test/benchmarks.go
@@ -48,17 +48,17 @@ func (s *Suite) BenchmarkLoadFile(t *testing.B) {
 			n, ierr = io.ReadFull(rd, buf)
 			return ierr
 		})
-		if err != nil {
+
+		t.StopTimer()
+		switch {
+		case err != nil:
 			t.Fatal(err)
-		}
-
-		if n != length {
+		case n != length:
 			t.Fatalf("wrong number of bytes read: want %v, got %v", length, n)
-		}
-
-		if !bytes.Equal(data, buf) {
+		case !bytes.Equal(data, buf):
 			t.Fatalf("wrong bytes returned")
 		}
+		t.StartTimer()
 	}
 }
 
@@ -85,18 +85,17 @@ func (s *Suite) BenchmarkLoadPartialFile(t *testing.B) {
 			n, ierr = io.ReadFull(rd, buf)
 			return ierr
 		})
-		if err != nil {
+
+		t.StopTimer()
+		switch {
+		case err != nil:
 			t.Fatal(err)
-		}
-
-		if n != testLength {
+		case n != testLength:
 			t.Fatalf("wrong number of bytes read: want %v, got %v", testLength, n)
-		}
-
-		if !bytes.Equal(data[:testLength], buf) {
+		case !bytes.Equal(data[:testLength], buf):
 			t.Fatalf("wrong bytes returned")
 		}
-
+		t.StartTimer()
 	}
 }
 
@@ -124,17 +123,17 @@ func (s *Suite) BenchmarkLoadPartialFileOffset(t *testing.B) {
 			n, ierr = io.ReadFull(rd, buf)
 			return ierr
 		})
-		if err != nil {
+
+		t.StopTimer()
+		switch {
+		case err != nil:
 			t.Fatal(err)
-		}
-
-		if n != testLength {
+		case n != testLength:
 			t.Fatalf("wrong number of bytes read: want %v, got %v", testLength, n)
-		}
-
-		if !bytes.Equal(data[testOffset:testOffset+testLength], buf) {
+		case !bytes.Equal(data[testOffset:testOffset+testLength], buf):
 			t.Fatalf("wrong bytes returned")
 		}
+		t.StartTimer()
 
 	}
 }