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https://github.com/VictoriaMetrics/VictoriaMetrics.git
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f4989edd96
Previously bytesutil.Resize() was copying the original byte slice contents to a newly allocated slice. This wasted CPU cycles and memory bandwidth in some places, where the original slice contents wasn't needed after slize resizing. Switch such places to bytesutil.ResizeNoCopy(). Rename the original bytesutil.Resize() function to bytesutil.ResizeWithCopy() for the sake of improved readability. Additionally, allocate new slice with `make()` instead of `append()`. This guarantees that the capacity of the allocated slice exactly matches the requested size. The `append()` could return a slice with bigger capacity as an optimization for further `append()` calls. This could result in excess memory usage when the returned byte slice was cached (for instance, in lib/blockcache). Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2007
73 lines
1.8 KiB
Go
73 lines
1.8 KiB
Go
package bytesutil
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import (
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"bytes"
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"testing"
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)
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func TestResizeNoCopy(t *testing.T) {
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for i := 0; i < 1000; i++ {
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b := ResizeNoCopy(nil, i)
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if len(b) != i {
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t.Fatalf("invalid b size; got %d; expecting %d", len(b), i)
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}
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b1 := ResizeNoCopy(b, i)
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if len(b1) != len(b) || (len(b) > 0 && &b1[0] != &b[0]) {
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t.Fatalf("invalid b1; got %x; expecting %x", &b1[0], &b[0])
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}
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b2 := ResizeNoCopy(b[:0], i)
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if len(b2) != len(b) || (len(b) > 0 && &b2[0] != &b[0]) {
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t.Fatalf("invalid b2; got %x; expecting %x", &b2[0], &b[0])
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}
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if i > 0 {
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b[0] = 123
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b3 := ResizeNoCopy(b, i+1)
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if len(b3) != i+1 {
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t.Fatalf("invalid b3 len; got %d; want %d", len(b3), i+1)
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}
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if &b3[0] == &b[0] {
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t.Fatalf("b3 must be newly allocated")
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}
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if b3[0] != 0 {
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t.Fatalf("b3[0] must be zeroed; got %d", b3[0])
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}
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}
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}
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}
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func TestResizeWithCopy(t *testing.T) {
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for i := 0; i < 1000; i++ {
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b := ResizeWithCopy(nil, i)
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if len(b) != i {
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t.Fatalf("invalid b size; got %d; expecting %d", len(b), i)
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}
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b1 := ResizeWithCopy(b, i)
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if len(b1) != len(b) || (len(b) > 0 && &b1[0] != &b[0]) {
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t.Fatalf("invalid b1; got %x; expecting %x", &b1[0], &b[0])
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}
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b2 := ResizeWithCopy(b[:0], i)
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if len(b2) != len(b) || (len(b) > 0 && &b2[0] != &b[0]) {
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t.Fatalf("invalid b2; got %x; expecting %x", &b2[0], &b[0])
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}
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if i > 0 {
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b[0] = 123
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b3 := ResizeWithCopy(b, i+1)
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if len(b3) != i+1 {
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t.Fatalf("invalid b3 len; got %d; want %d", len(b3), i+1)
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}
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if &b3[0] == &b[0] {
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t.Fatalf("b3 must be newly allocated for i=%d", i)
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}
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if b3[0] != b[0] || b3[0] != 123 {
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t.Fatalf("b3[0] must equal b[0]; got %d; want %d", b3[0], b[0])
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}
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}
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}
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}
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func TestToUnsafeString(t *testing.T) {
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s := "str"
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if !bytes.Equal([]byte("str"), ToUnsafeBytes(s)) {
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t.Fatalf(`[]bytes(%s) doesnt equal to %s `, s, s)
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}
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}
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