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作为分析几个 golang 服务的一部分，我们看到所有服务都在 runtime.futex 函数中花费了 55% 到 70% 的时间。

请注意，这些服务涉及使用 goroutines、锁和通道来实现 goroutines 之间的同步和通信。

这是意料之中的吗？我们应该只关心在非“运行时”函数上花费的时间，或者这可能是 goroutines/locks/channels 的错误使用造成的，导致 futex 调用中的这种开销？

(pprof) top20
Showing nodes accounting for 43.80s, 80.25% of 54.58s total
Dropped 654 nodes (cum <= 0.27s)
Showing top 20 nodes out of 156
      flat  flat%   sum%        cum   cum%
    31.05s 56.89% 56.89%     31.05s 56.89%  runtime.futex
     3.55s  6.50% 63.39%      4.51s  8.26%  runtime.cgocall
     2.25s  4.12% 67.52%      2.25s  4.12%  runtime.usleep
     1.14s  2.09% 69.60%      1.53s  2.80%  runtime.scanobject
     0.73s  1.34% 70.94%      1.56s  2.86%  syscall.Syscall
     0.71s  1.30% 72.24%      2.27s  4.16%  runtime.mallocgc

(pprof) top20
Showing nodes accounting for 12.49s, 95.93% of 13.02s total
Dropped 93 nodes (cum <= 0.07s)
Showing top 20 nodes out of 47
      flat  flat%   sum%        cum   cum%
     9.69s 74.42% 74.42%      9.69s 74.42%  runtime.futex
     1.25s  9.60% 84.02%      1.63s 12.52%  runtime.cgocall
     0.64s  4.92% 88.94%      0.64s  4.92%  runtime.usleep
     0.17s  1.31% 90.25%      0.22s  1.69%  runtime.timeSleepUntil
     0.11s  0.84% 91.09%      0.17s  1.31%  runtime.scanobject
     0.08s  0.61% 91.71%      0.08s  0.61%  runtime.nanotime1
     0.08s  0.61% 92.32%      0.26s  2.00%  runtime.retake
     0.07s  0.54% 92.86%      0.07s  0.54%  runtime.lock2
     0.07s  0.54% 93.39%      0.13s     1%  runtime.traceEventLocked
     0.06s  0.46% 93.86%      0.36s  2.76%  runtime.notetsleep_internal
     0.05s  0.38% 94.24%      0.13s     1%  runtime.mallocgc
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1 回答 1

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这对于一个做得不多的程序来说并不罕见。如果您的程序大部分时间都在等待某事发生，那么它通常会在 futex 中休眠。

于 2022-02-25T00:22:19.047 回答