我是boost :: asio的新手。试图运行
ab -n 20000 -c 5 -r http://127.0.0.1:9999/
每次16000请求后测试卡住。但它确实完成了。我也收到了很多失败的请求。
正在做什么代码：
代码如下：
#include <iostream>
#include <functional>
#include <string>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/thread.hpp>
#include <memory>
// global variable for service and acceptor
boost::asio::io_service ioService;
boost::asio::ip::tcp::acceptor accp(ioService);
// callback for accept
void onAccept(const boost::system::error_code &ec, shared_ptr<boost::asio::ip::tcp::socket> soc) {
using boost::asio::ip::tcp;
soc->send(boost::asio::buffer("In Accept"));
soc->shutdown(boost::asio::ip::tcp::socket::shutdown_send);
soc.reset(new tcp::socket(ioService));
accp.async_accept(*soc, [=](const boost::system::error_code &ec) {
onAccept(ec, soc);
});
}
int main(int argc, char *argv[]) {
using boost::asio::ip::tcp;
boost::asio::ip::tcp::resolver resolver(ioService);
try {
boost::asio::ip::tcp::resolver::query query("127.0.0.1", boost::lexical_cast<std::string>(9999));
boost::asio::ip::tcp::endpoint endpoint = *resolver.resolve(query);
accp.open(endpoint.protocol());
accp.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true));
accp.bind(endpoint);
cout << "Ready to accept @ 9999" << endl;
auto t1 = boost::thread([&]() { ioService.run(); });
accp.listen(boost::asio::socket_base::max_connections);
std::shared_ptr<tcp::socket> soc = make_shared<tcp::socket>(ioService);
accp.async_accept(*soc, [=](const boost::system::error_code &ec) { onAccept(ec, soc); });
t1.join();
} catch (std::exception &ex) {
std::cout << "[" << boost::this_thread::get_id() << "] Exception: " << ex.what() << std::endl;
}
}
为了完整性：
答案 0 :(得分：3)
首先，让我们更正确地做事。我已经将代码更改为使用独立的asio而不是boost one并使用c ++ 14功能。使用原始代码，我的更改会减少很多失败。
代码：
#include <iostream>
#include <functional>
#include <string>
#include <asio.hpp>
#include <thread>
#include <memory>
#include <system_error>
#include <chrono>
//global variable for service and acceptor
asio::io_service ioService;
asio::ip::tcp::acceptor accp(ioService);
const char* response = "HTTP/1.1 200 OK\r\n\r\n\r\n";
//callback for accept
void onAccept(const std::error_code& ec, std::shared_ptr<asio::ip::tcp::socket> soc)
{
using asio::ip::tcp;
soc->set_option(asio::ip::tcp::no_delay(true));
auto buf = new asio::streambuf;
asio::async_read_until(*soc, *buf, "\r\n\r\n",
[=](auto ec, auto siz) {
asio::write(*soc, asio::buffer(response, std::strlen(response)));
soc->shutdown(asio::ip::tcp::socket::shutdown_send);
delete buf;
soc->close();
});
auto nsoc = std::make_shared<tcp::socket>(ioService);
//soc.reset(new tcp::socket(ioService));
accp.async_accept(*nsoc, [=](const std::error_code& ec){
onAccept(ec, nsoc);
});
}
int main( int argc, char * argv[] )
{
using asio::ip::tcp;
asio::ip::tcp::resolver resolver(ioService);
try{
asio::ip::tcp::resolver::query query(
"127.0.0.1",
std::to_string(9999)
);
asio::ip::tcp::endpoint endpoint = *resolver.resolve( query );
accp.open( endpoint.protocol() );
accp.set_option( asio::ip::tcp::acceptor::reuse_address( true ) );
accp.bind( endpoint );
std::cout << "Ready to accept @ 9999" << std::endl;
auto t1 = std::thread([&]() { ioService.run(); });
auto t2 = std::thread([&]() { ioService.run(); });
accp.listen( 1000 );
std::shared_ptr<tcp::socket> soc = std::make_shared<tcp::socket>(ioService);
accp.async_accept(*soc, [=](const std::error_code& ec) {
onAccept(ec, soc);
});
t1.join();
t2.join();
} catch(const std::exception & ex){
std::cout << "[" << std::this_thread::get_id()
<< "] Exception: " << ex.what() << std::endl;
} catch (...) {
std::cerr << "Caught unknown exception" << std::endl;
}
}
主要变化是：
使用的测试命令：ab -n 20000 -c 1 -r http://127.0.0.1:9999/
在Linux上，测试通过而没有任何错误，并且没有使用io_service的其他线程。
但是，在Mac上，我能够重现这个问题，即在处理了16000个请求后它被卡住了。那一刻的流程样本是：
Call graph:
906 Thread_1887605 DispatchQueue_1: com.apple.main-thread (serial)
+ 906 start (in libdyld.dylib) + 1 [0x7fff868bc5c9]
+ 906 main (in server_hangs_so) + 2695 [0x10d3622b7]
+ 906 std::__1::thread::join() (in libc++.1.dylib) + 20 [0x7fff86ad6ba0]
+ 906 __semwait_signal (in libsystem_kernel.dylib) + 10 [0x7fff8f44c48a]
906 Thread_1887609
+ 906 thread_start (in libsystem_pthread.dylib) + 13 [0x7fff8d0983ed]
+ 906 _pthread_start (in libsystem_pthread.dylib) + 176 [0x7fff8d09afd7]
+ 906 _pthread_body (in libsystem_pthread.dylib) + 131 [0x7fff8d09b05a]
+ 906 void* std::__1::__thread_proxy<std::__1::tuple<main::$_2> >(void*) (in server_hangs_so) + 124 [0x10d36317c]
+ 906 asio::detail::scheduler::run(std::__1::error_code&) (in server_hangs_so) + 181 [0x10d36bc25]
+ 906 asio::detail::scheduler::do_run_one(asio::detail::scoped_lock<asio::detail::posix_mutex>&, asio::detail::scheduler_thread_info&, std::__1::error_code const&) (in server_hangs_so) + 393 [0x10d36bfe9]
+ 906 kevent (in libsystem_kernel.dylib) + 10 [0x7fff8f44d21a]
906 Thread_1887610
906 thread_start (in libsystem_pthread.dylib) + 13 [0x7fff8d0983ed]
906 _pthread_start (in libsystem_pthread.dylib) + 176 [0x7fff8d09afd7]
906 _pthread_body (in libsystem_pthread.dylib) + 131 [0x7fff8d09b05a]
906 void* std::__1::__thread_proxy<std::__1::tuple<main::$_3> >(void*) (in server_hangs_so) + 124 [0x10d36324c]
906 asio::detail::scheduler::run(std::__1::error_code&) (in server_hangs_so) + 181 [0x10d36bc25]
906 asio::detail::scheduler::do_run_one(asio::detail::scoped_lock<asio::detail::posix_mutex>&, asio::detail::scheduler_thread_info&, std::__1::error_code const&) (in server_hangs_so) + 263 [0x10d36bf67]
906 __psynch_cvwait (in libsystem_kernel.dylib) + 10 [0x7fff8f44c136]
Total number in stack (recursive counted multiple, when >=5):
Sort by top of stack, same collapsed (when >= 5):
__psynch_cvwait (in libsystem_kernel.dylib) 906
__semwait_signal (in libsystem_kernel.dylib) 906
kevent (in libsystem_kernel.dylib) 906
只有在提供了额外的线程后，我才能通过以下结果完成测试：
Benchmarking 127.0.0.1 (be patient)
Completed 2000 requests
Completed 4000 requests
Completed 6000 requests
Completed 8000 requests
Completed 10000 requests
Completed 12000 requests
Completed 14000 requests
Completed 16000 requests
Completed 18000 requests
Completed 20000 requests
Finished 20000 requests
Server Software:
Server Hostname: 127.0.0.1
Server Port: 9999
Document Path: /
Document Length: 2 bytes
Concurrency Level: 1
Time taken for tests: 33.328 seconds
Complete requests: 20000
Failed requests: 3
(Connect: 1, Receive: 1, Length: 1, Exceptions: 0)
Total transferred: 419979 bytes
HTML transferred: 39998 bytes
Requests per second: 600.09 [#/sec] (mean)
Time per request: 1.666 [ms] (mean)
Time per request: 1.666 [ms] (mean, across all concurrent requests)
Transfer rate: 12.31 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 30.7 0 4346
Processing: 0 1 184.4 0 26075
Waiting: 0 0 0.0 0 1
Total: 0 2 186.9 0 26075
Percentage of the requests served within a certain time (ms)
50% 0
66% 0
75% 0
80% 0
90% 0
95% 0
98% 0
99% 0
100% 26075 (longest request)
可能卡住的线程的堆栈跟踪：
* thread #3: tid = 0x0002, 0x00007fff8f44d21a libsystem_kernel.dylib`kevent + 10, stop reason = signal SIGSTOP
* frame #0: 0x00007fff8f44d21a libsystem_kernel.dylib`kevent + 10
frame #1: 0x0000000109c482ec server_hangs_so`asio::detail::kqueue_reactor::run(bool, asio::detail::op_queue<asio::detail::scheduler_operation>&) + 268
frame #2: 0x0000000109c48039 server_hangs_so`asio::detail::scheduler::do_run_one(asio::detail::scoped_lock<asio::detail::posix_mutex>&, asio::detail::scheduler_thread_info&, std::__1::error_code const&) + 393
frame #3: 0x0000000109c47c75 server_hangs_so`asio::detail::scheduler::run(std::__1::error_code&) + 181
frame #4: 0x0000000109c3f2fc server_hangs_so`void* std::__1::__thread_proxy<std::__1::tuple<main::$_3> >(void*) + 124
frame #5: 0x00007fff8d09b05a libsystem_pthread.dylib`_pthread_body + 131
frame #6: 0x00007fff8d09afd7 libsystem_pthread.dylib`_pthread_start + 176
frame #7: 0x00007fff8d0983ed libsystem_pthread.dylib`thread_start + 13
这可能是kqueue_reactor实施asio或mac系统本身（不太可能）的问题
<强>更新
libevent也观察到相同的行为。因此，asio实施不是问题。它必须是kqueue内核实现中的一些错误。在Linux上epoll没有看到这个问题。
答案 1 :(得分：2)
你的本地套接字已经用完了。您不应该通过从单个IP地址生成所有负载来进行测试。 （另外，你的负载生成器应该足够聪明，能够检测并解决这种情况，但很多人都没有。）