This repository has been archived by the owner on Jan 10, 2024. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 119
Optimize randBool() and randString() #41
Merged
Merged
Changes from all commits
Commits
Show all changes
4 commits
Select commit
Hold shift + click to select a range
File filter
Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
|
@@ -24,6 +24,7 @@ import ( | |
"time" | ||
|
||
"github.com/google/gofuzz/bytesource" | ||
"strings" | ||
) | ||
|
||
// fuzzFuncMap is a map from a type to a fuzzFunc that handles that type. | ||
|
@@ -495,10 +496,7 @@ var fillFuncMap = map[reflect.Kind]func(reflect.Value, *rand.Rand){ | |
|
||
// randBool returns true or false randomly. | ||
func randBool(r *rand.Rand) bool { | ||
if r.Int()&1 == 1 { | ||
return true | ||
} | ||
return false | ||
return r.Int31()&(1<<30) == 0 | ||
} | ||
|
||
type int63nPicker interface { | ||
|
@@ -526,11 +524,12 @@ var unicodeRanges = []charRange{ | |
// may include a variety of (valid) UTF-8 encodings. | ||
func randString(r *rand.Rand) string { | ||
n := r.Intn(20) | ||
runes := make([]rune, n) | ||
for i := range runes { | ||
runes[i] = unicodeRanges[r.Intn(len(unicodeRanges))].choose(r) | ||
sb := strings.Builder{} | ||
sb.Grow(n) | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. I bet |
||
for i := 0; i < n; i++ { | ||
sb.WriteRune(unicodeRanges[r.Intn(len(unicodeRanges))].choose(r)) | ||
} | ||
return string(runes) | ||
return sb.String() | ||
} | ||
|
||
// randUint64 makes random 64 bit numbers. | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Why bit 31 and not some other bit?
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
I had to pick one and I believe there was no better choice :)
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Yeah, they should all be the same. I just wasn't sure if the change from bit 0 was significant for the speed up--it shouldn't be, right?
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
From my benchmarks, on my local machine I've found this bit to be faster from bit 0 by 1-2% - why, I don't know - probably some CPU arch black magic.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
hm... you can use https://godoc.org/golang.org/x/tools/cmd/benchcmp to tell if it's significant or not. (not shown in the help: you can put multiple runs in both the old and new file and it will give you the std dev so you can tell if it's significant or not)