Edit report at https://bugs.php.net/bug.php?id=62658&edit=1
ID: 62658
Updated by: pierr...@php.net
Reported by: sopl dot wang at gmail dot com
Summary: When enable âwith-curlwrappers option,
stream_get_contents() may cpu 100%
-Status: Open
+Status: Feedback
Type: Bug
Package: cURL related
Operating System: ALL
PHP Version: master-Git-2012-07-25 (Git)
-Assigned To:
+Assigned To: pierrick
Block user comment: N
Private report: N
New Comment:
Do you still have this issue ? I tried on my local build and everything work as
expected. If it doesn't work could you give me more details about your build ?
libcurl version ?
Previous Comments:
------------------------------------------------------------------------
[2012-07-25 10:26:16] sopl dot wang at gmail dot com
Description:
------------
When enable `âwith-curlwrappers` option, with http(s)/ftp(s)/other
curl-wrapped
stream protocols, file_get_contents(), stream_get_contents() and alike
functions
may lead consume 100% cpu cycle on waiting for receive.
When `strace` problem php process, following will be develop:
<pre>
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
select(7, [6], [6], [], {15, 0}) = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0) = 0 (Timeout)
</pre>
The reason we found is in 'ext/curl/streams.c', function
php_curl_stream_read(),
line 174:
<code>
select(curlstream->maxfd + 1, &curlstream->readfds, &curlstream->writefds,
&curlstream->excfds, &tv)
</code>
When select(), `writefds` always can write and immediate return, no block at
here and, upper module will detect that no data could read and re-invoke this
function (`php_curl_stream_read()`), a nonblock loop, lead this consume 100%
cpu
bug.
If the link very slow, this 100% cpu problem may take the system load very high.
Test script:
---------------
Enable `âwith-curlwrappers` and test:
<code>
<?php
while (true)
file_get_contents('http://soplwang.com');
</code>
Expected result:
----------------
Expect the behavior like native php doesâ¦
When `strace`, native php generate:
<pre>
poll([{fd=3, events=POLLIN|POLLERR|POLLHUP}], 1, 60000) = 1 ([{fd=3,
revents=POLLIN}])
</pre>
Actual result:
--------------
When `strace`, generate:
<pre>
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
poll([{fd=3, events=POLLIN}], 1, 0) = 0 (Timeout)
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
poll([{fd=3, events=POLLIN}], 1, 0) = 0 (Timeout)
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
poll([{fd=3, events=POLLIN}], 1, 0) = 0 (Timeout)
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
poll([{fd=3, events=POLLIN}], 1, 0) = 0 (Timeout)
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
poll([{fd=3, events=POLLIN}], 1, 0) = 0 (Timeout)
...
</pre>
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=62658&edit=1
