blocks|key|1575763|text|pow(363,100000000000000)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1575764|如果一个大的计算量。它需要时间来处理并给出结果。|unstyled|1575765|简单的计算：|1575766|>>>+import+time
>>>+def+test(power):
...+++++start+=+time.time()
...+++++pow(363,+power)
...+++++return+time.time()+-+start
...
>>>+for+power+in+range(1,11):
...+++++print(test(pow(10,+power)))
...
6.198883056640625e-06
2.1457672119140625e-06
3.0517578125e-05
0.0009307861328125
0.0421295166015625
1.7541508674621582+#This+is+a+(363,+1000000)|1575767|时间呈指数增长|1575768|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|P|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$B|C]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|F|7|T|8|@]|9|@]|A|$]]]|N|$]]

<pre><code>pow(363,100000000000000)
</code></pre>

if a big computation. It takes times for it to process and give the result

simple computation:

<pre><code>&gt;&gt;&gt; import time
&gt;&gt;&gt; def test(power):
... start = time.time()
... pow(363, power)
... return time.time() - start
...
&gt;&gt;&gt; for power in range(1,11):
... print(test(pow(10, power)))
...
6.198883056640625e-06
2.1457672119140625e-06
3.0517578125e-05
0.0009307861328125
0.0421295166015625
1.7541508674621582 #This is a (363, 1000000)
</code></pre>

Time increases exponentially

blocks|key|1575846|text|这是因为Python的全局解释器锁(GIL)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1575847|如果您查看函数的字节码：|1575848|import+time

def+blocking():
++++i+=+0
++++while+True:
++++++++time.sleep(1)
++++++++i%2B=1
++++++++print("block",i)
++++++++if+i>3:
++++++++++++print("Starting+pow....")
++++++++++++break
++++block=+pow(363,100000000000000)
++++return+True

import+dis

dis.dis(blocking)|code-block|syntax|javascript|1575849|它看起来像这样：|1575850|++4+++++++++++0+LOAD_CONST+++++++++++++++1+(0)
++++++++++++++2+STORE_FAST+++++++++++++++0+(i)

++5+++++++++++4+SETUP_LOOP++++++++++++++50+(to+56)

++6+++++>>++++6+LOAD_GLOBAL++++++++++++++0+(time)
++++++++++++++8+LOAD_METHOD++++++++++++++1+(sleep)
+++++++++++++10+LOAD_CONST+++++++++++++++2+(1)
+++++++++++++12+CALL_METHOD++++++++++++++1
+++++++++++++14+POP_TOP

++7++++++++++16+LOAD_FAST++++++++++++++++0+(i)
+++++++++++++18+LOAD_CONST+++++++++++++++2+(1)
+++++++++++++20+INPLACE_ADD
+++++++++++++22+STORE_FAST+++++++++++++++0+(i)

++8++++++++++24+LOAD_GLOBAL++++++++++++++2+(print)
+++++++++++++26+LOAD_CONST+++++++++++++++3+('block')
+++++++++++++28+LOAD_FAST++++++++++++++++0+(i)
+++++++++++++30+CALL_FUNCTION++++++++++++2
+++++++++++++32+POP_TOP

++9++++++++++34+LOAD_FAST++++++++++++++++0+(i)
+++++++++++++36+LOAD_CONST+++++++++++++++4+(3)
+++++++++++++38+COMPARE_OP+++++++++++++++4+(>)
+++++++++++++40+POP_JUMP_IF_FALSE++++++++6

+10++++++++++42+LOAD_GLOBAL++++++++++++++2+(print)
+++++++++++++44+LOAD_CONST+++++++++++++++5+('Starting+pow....')
+++++++++++++46+CALL_FUNCTION++++++++++++1
+++++++++++++48+POP_TOP

+11++++++++++50+BREAK_LOOP
+++++++++++++52+JUMP_ABSOLUTE++++++++++++6
+++++++++++++54+POP_BLOCK

+12+++++>>+++56+LOAD_GLOBAL++++++++++++++3+(pow)
+++++++++++++58+LOAD_CONST+++++++++++++++6+(363)
+++++++++++++60+LOAD_CONST+++++++++++++++7+(100000000000000)
+++++++++++++62+CALL_FUNCTION++++++++++++2
+++++++++++++64+STORE_FAST+++++++++++++++1+(block)

+13++++++++++66+LOAD_CONST+++++++++++++++8+(True)
+++++++++++++68+RETURN_VALUE|1575851|您将注意到，pow调用在第62位作为单个字节码指令发生。GIL只能在字节码之间传递，所以由于pow(363,100000000000000)需要很长时间才能执行，所以另一个线程在执行期间没有机会运行。|offset|length|style|CODE|1575852|entityMap^0|0|0|0|0|0|6|3|1A|O|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|Z|8|@$O|10|P|11|Q|R]|$O|12|P|13|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|T|$]]

This is because of Python's global interpreter lock (GIL).

If you look at the bytecode for your function:

<pre><code>import time

def blocking():
 i = 0
 while True:
 time.sleep(1)
 i+=1
 print("block",i)
 if i&gt;3:
 print("Starting pow....")
 break
 block= pow(363,100000000000000)
 return True

import dis

dis.dis(blocking)
</code></pre>

which looks like this:

<pre><code> 4 0 LOAD_CONST 1 (0)
 2 STORE_FAST 0 (i)

 5 4 SETUP_LOOP 50 (to 56)

 6 &gt;&gt; 6 LOAD_GLOBAL 0 (time)
 8 LOAD_METHOD 1 (sleep)
 10 LOAD_CONST 2 (1)
 12 CALL_METHOD 1
 14 POP_TOP

 7 16 LOAD_FAST 0 (i)
 18 LOAD_CONST 2 (1)
 20 INPLACE_ADD
 22 STORE_FAST 0 (i)

 8 24 LOAD_GLOBAL 2 (print)
 26 LOAD_CONST 3 ('block')
 28 LOAD_FAST 0 (i)
 30 CALL_FUNCTION 2
 32 POP_TOP

 9 34 LOAD_FAST 0 (i)
 36 LOAD_CONST 4 (3)
 38 COMPARE_OP 4 (&gt;)
 40 POP_JUMP_IF_FALSE 6

 10 42 LOAD_GLOBAL 2 (print)
 44 LOAD_CONST 5 ('Starting pow....')
 46 CALL_FUNCTION 1
 48 POP_TOP

 11 50 BREAK_LOOP
 52 JUMP_ABSOLUTE 6
 54 POP_BLOCK

 12 &gt;&gt; 56 LOAD_GLOBAL 3 (pow)
 58 LOAD_CONST 6 (363)
 60 LOAD_CONST 7 (100000000000000)
 62 CALL_FUNCTION 2
 64 STORE_FAST 1 (block)

 13 66 LOAD_CONST 8 (True)
 68 RETURN_VALUE
</code></pre>

You'll notice that the <code>pow</code> call happens at 62 as a single bytecode instruction. The GIL can only be handed off between bytecodes, so since <code>pow(363,100000000000000)</code> takes a long time to execute, the other thread doesn't get a chance to run during it.

Even though the first example about the ThreadPoolExecutor uses the pow function ( <a href="https://docs.python.org/3/library/concurrent.futures.html" rel="nofollow noreferrer">https://docs.python.org/3/library/concurrent.futures.html</a> ) it seems that using pow abnormally blocks all threads when called. See code below.

<pre class="lang-py prettyprint-override"><code>from concurrent.futures import ThreadPoolExecutor
import time

executor = ThreadPoolExecutor(max_workers=16)

def blocking():
 i = 0
 while True:
 time.sleep(1)
 i+=1
 print("block",i)
 if i&gt;3:
 print("Starting pow....")
 break
 block= pow(363,100000000000000)
 return True

def non_blocking():
 i = 0
 while True:
 time.sleep(1)
 i+=1
 print("non",i)

 return True

f1 = executor.submit(blocking)
f2 = executor.submit(non_blocking)
</code></pre>

I expected the output:

<pre><code>block 1
non 1
block 2
non 2
block 3
non 3
block 4
Starting pow....
non 4
non 5
non 6
non 7
non 8
</code></pre>

but the program stops running after "starting pow...." giving the result:

<pre><code>block 1
non 1
block 2
non 2
block 3
non 3
block 4
Starting pow....
</code></pre>

pow function blocking all threads with ThreadPoolExecutor

解释器

Python

尽管关于ThreadPoolExecutor的第一个示例使用了pow函数(  )，但是使用pow似乎会在被调用时异常地阻塞所有线程。请参阅下面的代码。from concurrent.futures import ThreadPoolExecutorimport timeexecutor = ThreadPoolExec...

问使用ThreadPoolExecutor阻塞所有线程的pow函数
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