• Dmitriy Vyukov's avatar
    net: add special netFD mutex · 23e15f72
    Dmitriy Vyukov authored
    The mutex, fdMutex, handles locking and lifetime of sysfd,
    and serializes Read and Write methods.
    This allows to strip 2 sync.Mutex.Lock calls,
    2 sync.Mutex.Unlock calls, 1 defer and some amount
    of misc overhead from every network operation.
    
    On linux/amd64, Intel E5-2690:
    benchmark                             old ns/op    new ns/op    delta
    BenchmarkTCP4Persistent                    9595         9454   -1.47%
    BenchmarkTCP4Persistent-2                  8978         8772   -2.29%
    BenchmarkTCP4ConcurrentReadWrite           4900         4625   -5.61%
    BenchmarkTCP4ConcurrentReadWrite-2         2603         2500   -3.96%
    
    In general it strips 70-500 ns from every network operation depending
    on processor model. On my relatively new E5-2690 it accounts to ~5%
    of network op cost.
    
    Fixes #6074.
    
    R=golang-dev, bradfitz, alex.brainman, iant, mikioh.mikioh
    CC=golang-dev
    https://golang.org/cl/12418043
    23e15f72
sendfile_linux.go 1.61 KB