adapt to pingcap-incubator (#1)

Signed-off-by: zhongzc <[email protected]>

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        go-version: [1.13.x, 1.14.x]
+        platform: [ubuntu-latest, macos-latest]
+
+    runs-on: ${{ matrix.platform }}
+
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Test
+        run: go test ./...
+      - name: Bench
+        run: go test -bench=./...

CONTRIBUTING.md

@@ -0,0 +1,3 @@
+# Contribution Guide
+
+Please refer to PingCAP [CONTRIBUTING.md](https://github.com/pingcap/community/blob/master/CONTRIBUTING.md)

OWNERS

@@ -0,0 +1,3 @@
+committers:
+  # TODO: in your repo created from this template, you should list the
+  # project committers below

README.md

@@ -1,14 +1,18 @@
-# minitrace-go
+# Minitrace-go
+[![Actions Status](https://github.com/pingcap-incubator/minitrace-go/workflows/CI/badge.svg)](https://github.com/pingcap-incubator/minitrace-go/actions)
+[![LICENSE](https://img.shields.io/github/license/pingcap-incubator/minitrace-go.svg)](https://github.com/pingcap-incubator/minitrace-go/blob/master/LICENSE)
+
+A high-performance, ergonomic timeline tracing library for Golang. 
 
 ## Basic Usage
 
 ```go
 package main
 
 import (
-    "fmt"
     "context"
-    "github.com/zhongzc/minitrace-go"
+    "fmt"
+    "github.com/pingcap-incubator/minitrace-go"
 )
 
 func tracedFunc(ctx context.Context, event uint32) {

buffer_list.go

@@ -1,3 +1,5 @@
+// Copyright 2020 TiKV Project Authors. Licensed under Apache-2.0.
+
 package minitrace
 
 import (

code-of-conduct.md

@@ -0,0 +1,3 @@
+# PingCAP Community Code of Conduct
+
+Please refer to our [PingCAP Community Code of Conduct](https://github.com/pingcap/community/blob/master/CODE_OF_CONDUCT.md)

context.go

@@ -1,3 +1,5 @@
+// Copyright 2020 TiKV Project Authors. Licensed under Apache-2.0.
+
 package minitrace
 
 import (
@@ -39,6 +41,7 @@ func (s spanContext) Value(key interface{}) interface{} {
     }
 }
 
+// Represents a per goroutine buffer
 type localSpans struct {
     spans        *bufferList
     createTimeNs uint64

minitrace.go

@@ -1,3 +1,5 @@
+// Copyright 2020 TiKV Project Authors. Licensed under Apache-2.0.
+
 package minitrace
 
 type SpanSet struct {

minitrace_test.go

@@ -1,3 +1,5 @@
+// Copyright 2020 TiKV Project Authors. Licensed under Apache-2.0.
+
 package minitrace
 
 import (

time.go

@@ -1,3 +1,5 @@
+// Copyright 2020 TiKV Project Authors. Licensed under Apache-2.0.
+
 package minitrace
 
 import (
@@ -10,10 +12,18 @@ func nanotime() int64
 //go:linkname walltime runtime.walltime
 func walltime() (sec int64, nsec int32)
 
+// Standard library's `time.Now()` will invoke two syscalls in Linux, one for `CLOCK_REALTIME`,
+// another for `CLOCK_MONOTONIC`. In our case, we'd like to separate these two calls to measure
+// time for performance purpose.
+// `nanotime()` is identical to Linux's `clock_gettime(CLOCK_MONOTONIC, &ts)`
 func monotimeNs() uint64 {
     return uint64(nanotime())
 }
 
+// Standard library's `time.Now()` will invoke two syscalls in Linux, one for `CLOCK_REALTIME`,
+// another for `CLOCK_MONOTONIC`. In our case, we'd like to separate these two calls to measure
+// time for performance purpose.
+// `nanotime()` is identical to Linux's `clock_gettime(CLOCK_REALTIME, &ts)`
 func realtimeNs() uint64 {
     sec, nsec := walltime()
     return uint64(sec*1_000_000_000 + int64(nsec))

trace.go

@@ -1,3 +1,5 @@
+// Copyright 2020 TiKV Project Authors. Licensed under Apache-2.0.
+
 package minitrace
 
 import (
@@ -42,6 +44,7 @@ func NewSpanWithContext(ctx context.Context, event uint32) (context.Context, Spa
 
 func NewSpan(ctx context.Context, event uint32) (res SpanHandle) {
     if s, ok := ctx.(spanContext); ok {
+        // We'd like to modify the context on "stack" directly to eliminate heap memory allocation
         res.spanContext = s
     } else if s, ok := ctx.Value(activeTracingKey).(spanContext); ok {
         res.spanContext.parent = ctx
@@ -56,43 +59,45 @@ func NewSpan(ctx context.Context, event uint32) (res SpanHandle) {
     id := atomic.AddUint32(&res.spanContext.tracingContext.maxId, 1)
     goid := gid.Get()
 
-    if goid == res.spanContext.currentGid {
-        slot := res.spanContext.tracedSpans.spans.slot()
+    // Use per goroutine buffer to reduce synchronization overhead.
+    if goid != res.spanContext.currentGid {
+        bl := newBufferList()
+        slot := bl.slot()
         slot.Id = id
         slot.Parent = res.spanContext.currentId
         slot.BeginNs = monotimeNs()
         slot.Event = event
 
-        res.spanContext.tracedSpans.refCount += 1
+        res.spanContext.tracedSpans = &localSpans{
+            spans:        bl,
+            createTimeNs: realtimeNs(),
+            refCount:     1,
+        }
         res.spanContext.currentId = id
         res.spanContext.currentGid = goid
         res.endNs = &slot.EndNs
-        return
     } else {
-        bl := newBufferList()
-        slot := bl.slot()
+        slot := res.spanContext.tracedSpans.spans.slot()
         slot.Id = id
         slot.Parent = res.spanContext.currentId
         slot.BeginNs = monotimeNs()
         slot.Event = event
 
-        res.spanContext.tracedSpans = &localSpans{
-            spans:        bl,
-            createTimeNs: realtimeNs(),
-            refCount:     1,
-        }
+        res.spanContext.tracedSpans.refCount += 1
         res.spanContext.currentId = id
         res.spanContext.currentGid = goid
         res.endNs = &slot.EndNs
-        return
     }
+
+    return
 }
 
 type SpanHandle struct {
     spanContext spanContext
     endNs       *uint64
 }
 
+// TODO: Prevent users from calling twice
 func (hd *SpanHandle) Finish() {
     if hd.endNs != nil {
         *hd.endNs = monotimeNs()