Hi, all
I took some times to setup a stress test for mod_fcgid, to see is there any
other concurrency bottleneck left, it seems fine to me.
I did a stress test with callgrind on mod_fcgid, this is the big picture:
http://people.apache.org/~pqf/mod_fcgid_performance/performance.png and this is
the output of callgrind:
http://people.apache.org/~pqf/mod_fcgid_performance/callgrind.out
As we can see, most cpu time are used in ap_create_environment() +
init_environment(). ap_create_environment() copy environment vars to a char[][]
buffer, and init_environment() copy char[][] to a char[] buffer for FCGI
protocol. I have to keep using ap_create_environment() to be compatible with
other cgi modules(cgid, cgi...), I will not shortcut these two calls for less
cpu utils.
And I make a strace trace to the system calls, to make sure there is no obvious
IO throughput bottleneck, and no luck either
4622 13:17:16.737888 ... futex resumed ) = 0
4622 13:17:16.737920 futex(0x95ce65c, FUTEX_WAKE, 1 unfinished ...
4622 13:17:16.738038 ... futex resumed ) = 0
4622 13:17:16.740735 gettimeofday({1346217436, 740787}, NULL) = 0
4622 13:17:16.740835 getsockname(12, {sa_family=AF_INET6,
sin6_port=htons(8080), inet_pton(AF_INET6, :::127.0.0.1, si
n6_addr), sin6_flowinfo=0, sin6_scope_id=0}, [28]) = 0
4622 13:17:16.741008 fcntl64(12, F_GETFL) = 0x2 (flags O_RDWR)
4622 13:17:16.741056 fcntl64(12, F_SETFL, O_RDWR|O_NONBLOCK) = 0
4622 13:17:16.741824 gettimeofday({1346217436, 741849}, NULL) = 0
4622 13:17:16.741890 gettimeofday({1346217436, 741911}, NULL) = 0
4622 13:17:16.741969 read(12, GET /fcgi-bin/foo.pl HTTP/1.0\r\nH..., 8000) =
97
4622 13:17:16.742049 gettimeofday({1346217436, 742070}, NULL) = 0
4622 13:17:16.742108 gettimeofday({1346217436, 742129}, NULL) = 0
4622 13:17:16.742165 gettimeofday({1346217436, 742185}, NULL) = 0
4622 13:17:16.74 gettimeofday({1346217436, 742242}, NULL) = 0
4622 13:17:16.742278 gettimeofday({1346217436, 742299}, NULL) = 0
4622 13:17:16.742345 gettimeofday({1346217436, 742367}, NULL) = 0
4622 13:17:16.742404 gettimeofday({1346217436, 742424}, NULL) = 0
4622 13:17:16.742467 stat64(/usr/local/apache2/htdocs/fcgi-bin/foo.pl,
{st_mode=S_IFREG|0755, st_size=229, ...}) = 0
4622 13:17:16.742697 semop(4292662, 0x17234c, 1) = 0
4622 13:17:16.742750 semop(4292662, 0x172358, 1) = 0
4622 13:17:16.742804 socket(PF_FILE, SOCK_STREAM, 0) = 13
4622 13:17:16.742864 connect(13, {sa_family=AF_FILE,
path=/usr/local/apache2/logs/fcgidsock/4617.11}, 110) = 0
4622 13:17:16.743028 fcntl64(13, F_GETFL) = 0x2 (flags O_RDWR)
4622 13:17:16.743074 fcntl64(13, F_SETFL, O_RDWR|O_NONBLOCK) = 0
4622 13:17:16.743118 gettimeofday({1346217436, 743138}, NULL) = 0
4622 13:17:16.743174 writev(13, [{\1\1\0\1\0\10\0\0, 8},
{\0\1\0\0\0\0\0\0, 8}, {\1\4\0\1\3U\0\0, 8}, {\t\30UNIQUE_ID
UD2l3MCoqlsAABILpXoAA..., 853}, {\1\4\0\1\0\0\0\0, 8}, {\1\5\0\1\0\0\0\0,
8}], 6) = 893
4622 13:17:16.743337 read(13, 0xa6f4c5b8, 8192) = -1 EAGAIN (Resource
temporarily unavailable)
4622 13:17:16.743386 poll([{fd=13, events=POLLIN, revents=POLLIN}], 1, 4)
= 1
4622 13:17:16.743789 read(13, \1\6\0\1\3\266\2\0Content-Type: text/plain...,
8192) = 984
4622 13:17:16.743879 gettimeofday( unfinished ...
4622 13:17:16.743968 ... gettimeofday resumed {1346217436, 743943}, NULL) = 0
4622 13:17:16.744037 close(13) = 0
4622 13:17:16.744101 semop(4292662, 0x17234c, 1) = 0
4622 13:17:16.744149 semop(4292662, 0x172358, 1) = 0
4622 13:17:16.744209 gettimeofday({1346217436, 744231}, NULL) = 0
4622 13:17:16.744266 gettimeofday({1346217436, 744287}, NULL) = 0
4622 13:17:16.744343 writev(12, [{HTTP/1.1 200 OK\r\nDate: Wed, 29 A...,
154}, {CONTEXT_DOCUMENT_ROOT=\/usr/loca..., 92
4}], 2 unfinished ...
4622 13:17:16.745033 ... writev resumed ) = 1078
4622 13:17:16.745076 gettimeofday({1346217436, 745098}, NULL) = 0
4622 13:17:16.745148 times({tms_utime=1416, tms_stime=1464, tms_cutime=0,
tms_cstime=0}) = 499844951
4622 13:17:16.745255 gettimeofday( unfinished ...
4622 13:17:16.745800 ... gettimeofday resumed {1346217436, 745791}, NULL) = 0
4622 13:17:16.746013 shutdown(12, 1 /* send */ unfinished ...
4622 13:17:16.746554 ... shutdown resumed ) = 0
4622 13:17:16.746625 gettimeofday( unfinished ...
4622 13:17:16.746684 ... gettimeofday resumed {1346217436, 746658}, NULL) = 0
4622 13:17:16.746765 epoll_ctl(11, EPOLL_CTL_ADD, 12, {EPOLLIN,
{u32=158210764, u64=158210764}} unfinished ...
4622 13:17:16.746833 ... epoll_ctl resumed ) = 0
4622 13:17:16.747587 gettimeofday( unfinished ...
4622 13:17:16.747904 ... gettimeofday resumed {1346217436, 747649}, NULL) = 0
4622 13:17:16.748672 futex(0x95ce690, FUTEX_WAIT, 176390, NULL unfinished ...
2012-09-05
pqf
发件人：pqf
发送时间：2012-08-28 09:34
主题：回复: Re: Re: Re: mod_fcgid concurrency bottleneck, issue#53693
收件人：devdev@httpd.apache.org
抄送：
So what can mod_fcgid do in this overloaded?
1. mod_fcgid get a request
2. mod_fcgid can't apply a free slot of
