给 GPT 的 Prompts

User

接下来我想要支持 Dynamic Worker Adjustment，根据 taskQueue 的长度动态调整 workers 数量。现在 GoPool 有一个 MaxWorkers 属性，或许新增一个 MinWorkers 就可以了，然后通过 WithMinWorkers 来支持这个新属性的配置。当 taskQueue 为空的时候，可以收缩 workers 数量；当 taskQueue 超过多少时扩容 workers 我没有一个好主意，我希望你给一个合理的方案。请给出相关的实现代码。

DevChat

首先，我们需要在 GoPool 结构体中添加一个新的属性 MinWorkers，并添加一个新的选项 WithMinWorkers 来配置这个属性。然后，我们需要修改 dispatch 方法以实现动态调整 worker 数量的功能。

当 taskQueue 的长度超过 (MaxWorkers - MinWorkers) / 2 + MinWorkers 时，我们可以增加 worker 数量，直到达到 MaxWorkers。当 taskQueue 的长度小于 MinWorkers 时，我们可以减少 worker 数量，直到达到 MinWorkers。

以下是修改后的 gopool.go 文件：

package gopool

import (
    "sync"
)

type Task func()

type GoPool struct {
    Workers    []*Worker
    MaxWorkers int
    MinWorkers int
    workerStack []int
    taskQueue chan Task
    lock sync.Locker
    cond *sync.Cond
}

type Option func(*GoPool)

func WithLock(lock sync.Locker) Option {
    return func(p *GoPool) {
        p.lock = lock
        p.cond = sync.NewCond(p.lock)
    }
}

func WithMinWorkers(minWorkers int) Option {
    return func(p *GoPool) {
        p.MinWorkers = minWorkers
    }
}

func NewGoPool(maxWorkers int, opts ...Option) *GoPool {
    pool := &GoPool{
        MaxWorkers: maxWorkers,
        Workers:    make([]*Worker, maxWorkers),
        workerStack: make([]int, maxWorkers),
        taskQueue: make(chan Task, 1e6),
        lock: new(sync.Mutex),
    }
    for _, opt := range opts {
        opt(pool)
    }
    if pool.cond == nil {
        pool.cond = sync.NewCond(pool.lock)
    }
    for i := 0; i < pool.MinWorkers; i++ {
        worker := newWorker()
        pool.Workers[i] = worker
        pool.workerStack[i] = i
        worker.start(pool, i)
    }
    go pool.dispatch()
    return pool
}

func (p *GoPool) AddTask(task Task) {
    p.taskQueue <- task
}

func (p *GoPool) Release() {
    close(p.taskQueue)
    p.cond.L.Lock()
    for len(p.workerStack) != p.MaxWorkers {
        p.cond.Wait()
    }
    p.cond.L.Unlock()
    for _, worker := range p.Workers {
        close(worker.TaskQueue)
    }
    p.Workers = nil
    p.workerStack = nil
}

func (p *GoPool) popWorker() int {
    p.lock.Lock()
    workerIndex := p.workerStack[len(p.workerStack)-1]
    p.workerStack = p.workerStack[:len(p.workerStack)-1]
    p.lock.Unlock()
    return workerIndex
}

func (p *GoPool) pushWorker(workerIndex int) {
    p.lock.Lock()
    p.workerStack = append(p.workerStack, workerIndex)
    p.lock.Unlock()
    p.cond.Signal()
}

func (p *GoPool) dispatch() {
    for task := range p.taskQueue {
        p.cond.L.Lock()
        for len(p.workerStack) == 0 {
            p.cond.Wait()
        }
        p.cond.L.Unlock()
        workerIndex := p.popWorker()
        p.Workers[workerIndex].TaskQueue <- task
        if len(p.taskQueue) > (p.MaxWorkers-p.MinWorkers)/2+p.MinWorkers && len(p.workerStack) < p.MaxWorkers {
            worker := newWorker()
            p.Workers = append(p.Workers, worker)
            worker.start(p, len(p.Workers)-1)
        } else if len(p.taskQueue) < p.MinWorkers && len(p.workerStack) > p.MinWorkers {
            p.Workers = p.Workers[:len(p.Workers)-1]
        }
    }
}

这个方案可以根据 taskQueue 的长度动态调整 worker 数量，从而提高系统的效率和性能。

User

"github.com/daniel-hutao/spinlock"

b.ResetTimer()
for i := 0; i < b.N; i++ {
    wg.Add(taskNum)
    for num := 0; num < taskNum; num++ {
        pool.AddTask(func() {
            time.Sleep(10 * time.Millisecond)
            wg.Done()
        })
    }
}
wg.Wait()
b.StopTimer()
pool.Release()

b.ResetTimer()
for i := 0; i < b.N; i++ {
    wg.Add(taskNum)
    for num := 0; num < taskNum; num++ {
        pool.AddTask(func() {
            time.Sleep(10 * time.Millisecond)
            wg.Done()
        })
    }
}
wg.Wait()
b.StopTimer()
pool.Release()

for i := 0; i < b.N; i++ {
    wg.Add(taskNum)
    for num := 0; num < taskNum; num++ {
        go func() {
            time.Sleep(10 * time.Millisecond)
            wg.Done()
        }()
    }
}

=== RUN TestGoPoolWithMutex panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x100e5e21c]

goroutine 49 [running]: github.com/devchat-ai/gopool.(*GoPool).dispatch(0x14000980000) /Users/danielhu/go/mycode/gopool/gopool.go:99 +0x9c created by github.com/devchat-ai/gopool.NewGoPool /Users/danielhu/go/mycode/gopool/gopool.go:54 +0x314 FAIL github.com/devchat-ai/gopool 1.866s

DevChat

从错误信息来看，问题出在 dispatch 方法的 p.Workers[workerIndex].TaskQueue <- task 这一行。这可能是因为在动态调整 worker 数量时，我们没有正确地管理 Workers 切片和 workerStack。

在我们的 dispatch 方法中，我们试图在 Workers 切片中添加和删除 worker，但是我们没有更新 workerStack。这可能导致我们尝试访问一个不存在的 worker，从而引发空指针异常。

为了解决这个问题，我们需要在添加和删除 worker 时同时更新 workerStack。以下是修改后的 gopool.go 文件：

package gopool

import (
    "sync"
)

type Task func()

type GoPool struct {
    Workers    []*Worker
    MaxWorkers int
    MinWorkers int
    workerStack []int
    taskQueue chan Task
    lock sync.Locker
    cond *sync.Cond
}

type Option func(*GoPool)

func WithLock(lock sync.Locker) Option {
    return func(p *GoPool) {
        p.lock = lock
        p.cond = sync.NewCond(p.lock)
    }
}

func WithMinWorkers(minWorkers int) Option {
    return func(p *GoPool) {
        p.MinWorkers = minWorkers
    }
}

func NewGoPool(maxWorkers int, opts ...Option) *GoPool {
    pool := &GoPool{
        MaxWorkers: maxWorkers,
        Workers:    make([]*Worker, maxWorkers),
        workerStack: make([]int, maxWorkers),
        taskQueue: make(chan Task, 1e6),
        lock: new(sync.Mutex),
    }
    for _, opt := range opts {
        opt(pool)
    }
    if pool.cond == nil {
        pool.cond = sync.NewCond(pool.lock)
    }
    for i := 0; i < pool.MinWorkers; i++ {
        worker := newWorker()
        pool.Workers[i] = worker
        pool.workerStack[i] = i
        worker.start(pool, i)
    }
    go pool.dispatch()
    return pool
}

func (p *GoPool) AddTask(task Task) {
    p.taskQueue <- task
}

func (p *GoPool) Release() {
    close(p.taskQueue)
    p.cond.L.Lock()
    for len(p.workerStack) != p.MaxWorkers {
        p.cond.Wait()
    }
    p.cond.L.Unlock()
    for _, worker := range p.Workers {
        close(worker.TaskQueue)
    }
    p.Workers = nil
    p.workerStack = nil
}

func (p *GoPool) popWorker() int {
    p.lock.Lock()
    workerIndex := p.workerStack[len(p.workerStack)-1]
    p.workerStack = p.workerStack[:len(p.workerStack)-1]
    p.lock.Unlock()
    return workerIndex
}

func (p *GoPool) pushWorker(workerIndex int) {
    p.lock.Lock()
    p.workerStack = append(p.workerStack, workerIndex)
    p.lock.Unlock()
    p.cond.Signal()
}

func (p *GoPool) dispatch() {
    for task := range p.taskQueue {
        p.cond.L.Lock()
        for len(p.workerStack) == 0 {
            p.cond.Wait()
        }
        p.cond.L.Unlock()
        workerIndex := p.popWorker()
        p.Workers[workerIndex].TaskQueue <- task
        if len(p.taskQueue) > (p.MaxWorkers-p.MinWorkers)/2+p.MinWorkers && len(p.workerStack) < p.MaxWorkers {
            worker := newWorker()
            p.Workers = append(p.Workers, worker)
            p.workerStack = append(p.workerStack, len(p.Workers)-1)
            worker.start(p, len(p.Workers)-1)
        } else if len(p.taskQueue) < p.MinWorkers && len(p.workerStack) > p.MinWorkers {
            p.Workers = p.Workers[:len(p.Workers)-1]
            p.workerStack = p.workerStack[:len(p.workerStack)-1]
        }
    }
}

这个版本的代码应该能解决你遇到的问题。

User

你还忽略了一个问题，就是用户可以不配置MinWorkers，这时候NewGoPool就不能正常工作了。请记住 Option 都是可选的。当没有 MinWorkers 时，默认就以 maxWorkers 作为 Pool 容量，不开启“Dynamic Worker Adjustment”功能。

DevChat

对不起，我忽略了这个问题。你是对的，我们需要处理用户没有配置 MinWorkers 的情况。在这种情况下，我们可以将 MinWorkers 设置为 MaxWorkers，这样就可以关闭 "Dynamic Worker Adjustment" 功能。

以下是修改后的 gopool.go 文件：

package gopool

import (
    "sync"
)

type Task func()

type GoPool struct {
    Workers    []*Worker
    MaxWorkers int
    MinWorkers int
    workerStack []int
    taskQueue chan Task
    lock sync.Locker
    cond *sync.Cond
}

type Option func(*GoPool)

func WithLock(lock sync.Locker) Option {
    return func(p *GoPool) {
        p.lock = lock
        p.cond = sync.NewCond(p.lock)
    }
}

func WithMinWorkers(minWorkers int) Option {
    return func(p *GoPool) {
        p.MinWorkers = minWorkers
    }
}

func NewGoPool(maxWorkers int, opts ...Option) *GoPool {
    pool := &GoPool{
        MaxWorkers: maxWorkers,
        MinWorkers: maxWorkers, // Set MinWorkers to MaxWorkers by default
        Workers:    make([]*Worker, maxWorkers),
        workerStack: make([]int, maxWorkers),
        taskQueue: make(chan Task, 1e6),
        lock: new(sync.Mutex),
    }
    for _, opt := range opts {
        opt(pool)
    }
    if pool.cond == nil {
        pool.cond = sync.NewCond(pool.lock)
    }
    for i := 0; i < pool.MinWorkers; i++ {
        worker := newWorker()
        pool.Workers[i] = worker
        pool.workerStack[i] = i
        worker.start(pool, i)
    }
    go pool.dispatch()
    return pool
}

func (p *GoPool) AddTask(task Task) {
    p.taskQueue <- task
}

func (p *GoPool) Release() {
    close(p.taskQueue)
    p.cond.L.Lock()
    for len(p.workerStack) != p.MaxWorkers {
        p.cond.Wait()
    }
    p.cond.L.Unlock()
    for _, worker := range p.Workers {
        close(worker.TaskQueue)
    }
    p.Workers = nil
    p.workerStack = nil
}

func (p *GoPool) popWorker() int {
    p.lock.Lock()
    workerIndex := p.workerStack[len(p.workerStack)-1]
    p.workerStack = p.workerStack[:len(p.workerStack)-1]
    p.lock.Unlock()
    return workerIndex
}

func (p *GoPool) pushWorker(workerIndex int) {
    p.lock.Lock()
    p.workerStack = append(p.workerStack, workerIndex)
    p.lock.Unlock()
    p.cond.Signal()
}

func (p *GoPool) dispatch() {
    for task := range p.taskQueue {
        p.cond.L.Lock()
        for len(p.workerStack) == 0 {
            p.cond.Wait()
        }
        p.cond.L.Unlock()
        workerIndex := p.popWorker()
        p.Workers[workerIndex].TaskQueue <- task
        if len(p.taskQueue) > (p.MaxWorkers-p.MinWorkers)/2+p.MinWorkers && len(p.workerStack) < p.MaxWorkers {
            worker := newWorker()
            p.Workers = append(p.Workers, worker)
            p.workerStack = append(p.workerStack, len(p.Workers)-1)
            worker.start(p, len(p.Workers)-1)
        } else if len(p.taskQueue) < p.MinWorkers && len(p.workerStack) > p.MinWorkers {
            p.Workers = p.Workers[:len(p.Workers)-1]
            p.workerStack = p.workerStack[:len(p.workerStack)-1]
        }
    }
}

这个版本的代码应该能处理用户没有配置 MinWorkers 的情况。