Edit report at https://bugs.php.net/bug.php?id=62658&edit=1
ID: 62658
User updated by: sopl dot wang at gmail dot com
Reported by: sopl dot wang at gmail dot com
Summary: When enable âwith-curlwrappers option,
stream_get_contents() may cpu 100%
Status: Assigned
Type: Bug
Package: cURL related
Operating System: ALL
PHP Version: master-Git-2012-07-25 (Git)
Assigned To: pierrick
Block user comment: N
Private report: N
New Comment:
You may try use `file_get_contents` to open a very slow website to help
reproduce
this problem. When open a very very slow website, this issue will be more
evident.
Previous Comments:
------------------------------------------------------------------------
[2012-10-07 13:49:51] sopl dot wang at gmail dot com
Still have issue (a bit different of output, but still cpu 100%) when I build
and test on php-5.4.7 GA release. Follow is my build config:
./configure --prefix=/usr/local/webserver/php5.4.7 --with-config-file-
path=/usr/local/webserver/php5.4.7/etc --with-mysql=/usr/local/webserver/mysql5
--with-mysqli=/usr/local/webserver/mysql5/bin/mysql_config
--with-iconv-dir=/usr
--with-freetype-dir --with-jpeg-dir --with-png-dir --with-zlib --with-libxml-
dir=/usr --enable-xml --disable-rpath --enable-bcmath --enable-shmop --enable-
sysvsem --enable-inline-optimization --with-curl=/usr --with-curlwrappers --
enable-ftp --enable-mbregex --enable-fpm --with-fpm-user=www --with-fpm-
group=www --disable-ipv6 --enable-mbstring --with-mcrypt --with-gd=/usr --
enable-gd-native-ttf --with-openssl --with-mhash --enable-pcntl
--enable-sockets
--enable-gd-jis-conv --disable-debug --enable-sysvshm --enable-soap --with-pdo-
mysql=shared,/usr/local/webserver/mysql5 --with-pdo-sqlite=shared --with-
sqlite=shared --enable-pdo=shared
Test script
-----------
./sapi/cli/php <<<'<?php while(1) file_get_contents("http://www.l4ka.org";);'
Output
------
poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
clock_gettime(CLOCK_MONOTONIC, {26871452, 912511643}) = 0
clock_gettime(CLOCK_MONOTONIC, {26871452, 912536643}) = 0
clock_gettime(CLOCK_MONOTONIC, {26871452, 912553643}) = 0
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
clock_gettime(CLOCK_MONOTONIC, {26871452, 912606643}) = 0
poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
clock_gettime(CLOCK_MONOTONIC, {26871452, 912643643}) = 0
clock_gettime(CLOCK_MONOTONIC, {26871452, 912668643}) = 0
clock_gettime(CLOCK_MONOTONIC, {26871452, 912685643}) = 0
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
clock_gettime(CLOCK_MONOTONIC, {26871452, 912738643}) = 0
poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
clock_gettime(CLOCK_MONOTONIC, {26871452, 912775643}) = 0
clock_gettime(CLOCK_MONOTONIC, {26871452, 912800643}) = 0
clock_gettime(CLOCK_MONOTONIC, {26871452, 912817643}) = 0
select(4, [3], [3], [], {15, 0}) = 1 (out [3], left {15, 0})
System version
--------------
LSB Version: :core-4.0-amd64:core-4.0-ia32:core-4.0-noarch:graphics-4.0-
amd64:graphics-4.0-ia32:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-
ia32:printing-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 5.6 (Final)
Release: 5.6
Codename: Final
Curl version
------------
curl 7.21.6 (x86_64-unknown-linux-gnu) libcurl/7.21.6 OpenSSL/0.9.8b zlib/1.2.3
libidn/0.6.5
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3
pop3s
rtsp smtp smtps telnet tftp
Features: IDN Largefile NTLM SSL libz
------------------------------------------------------------------------
[2012-09-28 19:44:39] [email protected]
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 ?
------------------------------------------------------------------------
[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
