unknown
1970-01-01 00:00:00 UTC
<div><br></div><div>2. I had tried this before, but ran into threading issu=
e, it made my app crash</div><div><br></div><div>3. So you suggest to use a=
global mutex to make sure when I am closing one socket, no async_read or a=
snyc_write operation happens on it in another thread.</div>
<div><br></div><div>4. I need to apply this mutex to all my read/write oper=
ations like this:</div><div>Sign is one connected object in my server app:<=
/div><div><br></div><div><div>void Sign::DoWrite(boost::shared_ptr<Messa=
ge> msg) {</div>
<div> write_msgs_.push_back(msg);</div><div> if (write_msgs_.si=
ze() =3D=3D 1) {</div><div> boost::shared_ptr<vector<cha=
r> > data(new vector<char>(400, 0));</div><div> ms=
g->Write(*data);</div><div>
</div><div> clientsPoolMutex.lock();</div><=
div> async_write(socket,</div><div> =
<div> }</div><div>}</div></div><div><br></div><div><br></div></div><d=
iv class=3D"gmail_extra"><div><br clear=3D"all"><div><div dir=3D"ltr">Dean =
Chen <br>Best regards<br><a href=3D"http://blog.csdn.net/csfreebird" t=
arget=3D"_blank">http://blog.csdn.net/csfreebird</a></div>
</div>
<br><br></div><div><div><div class=3D"gmail_quote">On Wed, Apr 2, 2014 at 1=
2:02 AM, Slav <span dir=3D"ltr"><<a href=3D"mailto:***@gmail.com" ta=
rget=3D"_blank">***@gmail.com</a>></span> wrote:<br><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;pad=
ding-left:1ex">
<div dir=3D"ltr"><div><div><div><div><div><div><div>To safely work with con=
nections asio::strand can be used:<br><br></div><div> //c=
reated once when io_service is created:<br></div> asio::s=
trand strand( io_service );<br>
<br> ...<br> <br></d=
iv> //at any moment connection must be "touched"=
;:<br></div><div> //no parallel async_read/write or handl=
e_accept() can be called since we're within asio::strand, but your serv=
er can start using clients so lock them in that case:<br>
</div> clientsPoolMutex.lock();<br><br></div> =
for each client in clients<br> {<br></div><div>&nb=
sp; //multiple harmless errors can aris=
e (connection was already closed, connection was forced to be close and so =
on) - just ignoring them is fine, but usage of overloaded function which do=
not accept error codes field can throw exceptions which can kill your serv=
er if not catch them:<br>
</div><div> asio::error_code shut=
downErrorCode;<br></div><div> asi=
o::error_code closeErrorCode;<br></div><div> &=
nbsp; <br></div><div> //sho=
uld be kicked due to being too old:<br></div> =
if ( client->lastMessageReceived < currentTime - ( 60 * =
60 ) )<br>
{<br></div> &nb=
sp; client->socket.shutdown( a=
sio::socket_base::shutdown_both, shutdownErrorCode );<br></div> =
client->socket.cl=
ose( closeErrorCode );<br> }<br>&=
nbsp; }<br><div><div> <br>
</div></div></div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_qu=
ote">2014-04-01 17:51 GMT+04:00 Dean Chen <span dir=3D"ltr"><<a href=3D"=
mailto:***@gmail.com" target=3D"_blank">***@gmail.com</a>>=
</span>:<div>
<div><br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">Hi, Slav:<br>
Thanks for your response. I used to create one thread to close the<b=
r>
connection if it's timeout. But this cause my process to crash. =
Because I<br>
cannot close one socket in another thread when there is another<br>
async_write or async_read operation on it.<br>
Accordin to this post:<br>
<a href=3D"http://web.archiveorange.com/archive/v/Q0J4VefPMc2v8QYvcV=
r3" target=3D"_blank">http://web.archiveorange.com/archive/v/Q0J4VefPMc2v8Q=
YvcVr3</a><br>
<br>
Most likely you have a threading issue in your program where you close a<br=
socket from one thread while simultaneously starting another async<br=
operation on the same socket from another thread. If you are sure thi=
s is<br>
not the case, please attach a small, complete program that exhibits t=
he<br>
problem. Thanks.<br>
<br>
Could you teach me your way, how to close the socket safely?<br>
<div><div><br>
Slav <<a href=3D"mailto:***@gmail.com" target=3D"_blank">***@gma=
il.com</a>> writes:<br>
<br>
> I had the same problem. Each day ~15000 users was connecting the<br>
> server but some of connections wasn't closed, so when ~500000<br>
> connections was hanging (some of them was live), server must be<br>
> restarted - it happened like each month-two.<br>
> Timers will significantly slow your server down, indeed. As was<br>
> answered to me in this mailing lists, it should be solved with<br>
> periodic iteration through all connections to kill any which hang too<=
br>
> much depending your inner server logic.<br>
> For my server I kick everyone who didn't sent anything to server f=
or<br>
> an hour. Kicking process is being invoked each 5 minutes. Iteration<br=
> through 10000 connections is lightning fast: takes less time than<br>
> human can measure (so less than 80 milliseconds) so it's possible =
to<br>
> run it each second but not needed.<br>
><br>
> 2014-04-01 16:46 GMT+04:00 =B3=C2=CA=E3 <<a href=3D"mailto:csfreebi=
***@gmail.com" target=3D"_blank">***@gmail.com</a>>:<br>
><br>
><br>
> Hi,<br>
> My server needs to handle thousands of TCP connections. =
But I find<br>
> many connections are not closed because async_read metho=
d blocks,<br>
> it's weird!<br>
> Today my server cannot work because there are too many T=
CP<br>
> connections, I have to restart OS.<br>
> I read a few articles which describes how to use dead li=
ne timer<br>
> with async_read, but I have some sad experience, thousan=
ds of<br>
> timers will slow down my server.<br>
> See my question on stackoverflow:<br>
> <a href=3D"http://stackoverflow.com/questions/22777835/i=
s-boostasio-asyn-read-" target=3D"_blank">http://stackoverflow.com/question=
s/22777835/is-boostasio-asyn-read-</a><br>
> with-timer-a-good-idea<br>
><br>
><br>
><br>
> My question is:<br>
> Why does my async_read blocks?<br>
> Can I use dead line timer in this case?<br>
><br>
><br>
><br>
> Dean Chen<br>
> Best regards<br>
> <a href=3D"http://blog.csdn.net/csfreebird" target=3D"_b=
lank">http://blog.csdn.net/csfreebird</a><br>
><br>
> --------------------------------------------------------=
-----------<br>
> -----------<br>
><br>
> _______________________________________________<br>
> asio-users mailing list<br>
> <a href=3D"mailto:asio-***@lists.sourceforge.net" targ=
et=3D"_blank">asio-***@lists.sourceforge.net</a><br>
> <a href=3D"https://lists.sourceforge.net/lists/listinfo/=
asio-users" target=3D"_blank">https://lists.sourceforge.net/lists/listinfo/=
asio-users</a><br>
> _______________________________________________<br>
> Using Asio? List your project at<br>
> <a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" t=
arget=3D"_blank">http://think-async.com/Asio/WhoIsUsingAsio</a><br>
><br>
><br>
><br>
> ----------------------------------------------------------------------=
--------<br>
> _______________________________________________<br>
> asio-users mailing list<br>
> <a href=3D"mailto:asio-***@lists.sourceforge.net" target=3D"_blank">=
asio-***@lists.sourceforge.net</a><br>
> <a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" ta=
rget=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a>=
<br>
> _______________________________________________<br>
> Using Asio? List your project at<br>
> <a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blan=
k">http://think-async.com/Asio/WhoIsUsingAsio</a><br>
<br>
---------------------------------------------------------------------------=
---<br>
_______________________________________________<br>
asio-users mailing list<br>
<a href=3D"mailto:asio-***@lists.sourceforge.net" target=3D"_blank">asio-=
***@lists.sourceforge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" target=
=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a><br>
_______________________________________________<br>
Using Asio? List your project at<br>
<a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blank">ht=
tp://think-async.com/Asio/WhoIsUsingAsio</a><br>
</div></div></blockquote></div></div></div><br></div>
<br>-----------------------------------------------------------------------=
-------<br>
<br>_______________________________________________<br>
asio-users mailing list<br>
<a href=3D"mailto:asio-***@lists.sourceforge.net" target=3D"_blank">asio-=
***@lists.sourceforge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" target=
=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a><br>
_______________________________________________<br>
Using Asio? List your project at<br>
<a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blank">ht=
tp://think-async.com/Asio/WhoIsUsingAsio</a><br>
<br></blockquote></div><br></div></div></div>
</blockquote></div><br></div></div></div></div><br>------------------------=
------------------------------------------------------<br>
<br>_______________________________________________<br>
asio-users mailing list<br>
<a href=3D"mailto:asio-***@lists.sourceforge.net">asio-***@lists.source=
forge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" target=
=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a><br>
_______________________________________________<br>
Using Asio? List your project at<br>
<a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blank">ht=
tp://think-async.com/Asio/WhoIsUsingAsio</a><br>
<br></blockquote></div><br></div>
--089e0158ab5c1aa96d04f60c99c1--
e, it made my app crash</div><div><br></div><div>3. So you suggest to use a=
global mutex to make sure when I am closing one socket, no async_read or a=
snyc_write operation happens on it in another thread.</div>
<div><br></div><div>4. I need to apply this mutex to all my read/write oper=
ations like this:</div><div>Sign is one connected object in my server app:<=
/div><div><br></div><div><div>void Sign::DoWrite(boost::shared_ptr<Messa=
ge> msg) {</div>
<div> write_msgs_.push_back(msg);</div><div> if (write_msgs_.si=
ze() =3D=3D 1) {</div><div> boost::shared_ptr<vector<cha=
r> > data(new vector<char>(400, 0));</div><div> ms=
g->Write(*data);</div><div>
</div><div> clientsPoolMutex.lock();</div><=
div> async_write(socket,</div><div> =
<div> strand_.wrap(=
bind(&Sign::AfterSend, shared_from_this(), _1, data)));</div><div> }</div><div>}</div></div><div><br></div><div><br></div></div><d=
iv class=3D"gmail_extra"><div><br clear=3D"all"><div><div dir=3D"ltr">Dean =
Chen <br>Best regards<br><a href=3D"http://blog.csdn.net/csfreebird" t=
arget=3D"_blank">http://blog.csdn.net/csfreebird</a></div>
</div>
<br><br></div><div><div><div class=3D"gmail_quote">On Wed, Apr 2, 2014 at 1=
2:02 AM, Slav <span dir=3D"ltr"><<a href=3D"mailto:***@gmail.com" ta=
rget=3D"_blank">***@gmail.com</a>></span> wrote:<br><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;pad=
ding-left:1ex">
<div dir=3D"ltr"><div><div><div><div><div><div><div>To safely work with con=
nections asio::strand can be used:<br><br></div><div> //c=
reated once when io_service is created:<br></div> asio::s=
trand strand( io_service );<br>
<br> ...<br> <br></d=
iv> //at any moment connection must be "touched"=
;:<br></div><div> //no parallel async_read/write or handl=
e_accept() can be called since we're within asio::strand, but your serv=
er can start using clients so lock them in that case:<br>
</div> clientsPoolMutex.lock();<br><br></div> =
for each client in clients<br> {<br></div><div>&nb=
sp; //multiple harmless errors can aris=
e (connection was already closed, connection was forced to be close and so =
on) - just ignoring them is fine, but usage of overloaded function which do=
not accept error codes field can throw exceptions which can kill your serv=
er if not catch them:<br>
</div><div> asio::error_code shut=
downErrorCode;<br></div><div> asi=
o::error_code closeErrorCode;<br></div><div> &=
nbsp; <br></div><div> //sho=
uld be kicked due to being too old:<br></div> =
if ( client->lastMessageReceived < currentTime - ( 60 * =
60 ) )<br>
{<br></div> &nb=
sp; client->socket.shutdown( a=
sio::socket_base::shutdown_both, shutdownErrorCode );<br></div> =
client->socket.cl=
ose( closeErrorCode );<br> }<br>&=
nbsp; }<br><div><div> <br>
</div></div></div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_qu=
ote">2014-04-01 17:51 GMT+04:00 Dean Chen <span dir=3D"ltr"><<a href=3D"=
mailto:***@gmail.com" target=3D"_blank">***@gmail.com</a>>=
</span>:<div>
<div><br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">Hi, Slav:<br>
Thanks for your response. I used to create one thread to close the<b=
r>
connection if it's timeout. But this cause my process to crash. =
Because I<br>
cannot close one socket in another thread when there is another<br>
async_write or async_read operation on it.<br>
Accordin to this post:<br>
<a href=3D"http://web.archiveorange.com/archive/v/Q0J4VefPMc2v8QYvcV=
r3" target=3D"_blank">http://web.archiveorange.com/archive/v/Q0J4VefPMc2v8Q=
YvcVr3</a><br>
<br>
Most likely you have a threading issue in your program where you close a<br=
socket from one thread while simultaneously starting another async<br=
operation on the same socket from another thread. If you are sure thi=
s is<br>
not the case, please attach a small, complete program that exhibits t=
he<br>
problem. Thanks.<br>
<br>
Could you teach me your way, how to close the socket safely?<br>
<div><div><br>
Slav <<a href=3D"mailto:***@gmail.com" target=3D"_blank">***@gma=
il.com</a>> writes:<br>
<br>
> I had the same problem. Each day ~15000 users was connecting the<br>
> server but some of connections wasn't closed, so when ~500000<br>
> connections was hanging (some of them was live), server must be<br>
> restarted - it happened like each month-two.<br>
> Timers will significantly slow your server down, indeed. As was<br>
> answered to me in this mailing lists, it should be solved with<br>
> periodic iteration through all connections to kill any which hang too<=
br>
> much depending your inner server logic.<br>
> For my server I kick everyone who didn't sent anything to server f=
or<br>
> an hour. Kicking process is being invoked each 5 minutes. Iteration<br=
> through 10000 connections is lightning fast: takes less time than<br>
> human can measure (so less than 80 milliseconds) so it's possible =
to<br>
> run it each second but not needed.<br>
><br>
> 2014-04-01 16:46 GMT+04:00 =B3=C2=CA=E3 <<a href=3D"mailto:csfreebi=
***@gmail.com" target=3D"_blank">***@gmail.com</a>>:<br>
><br>
><br>
> Hi,<br>
> My server needs to handle thousands of TCP connections. =
But I find<br>
> many connections are not closed because async_read metho=
d blocks,<br>
> it's weird!<br>
> Today my server cannot work because there are too many T=
CP<br>
> connections, I have to restart OS.<br>
> I read a few articles which describes how to use dead li=
ne timer<br>
> with async_read, but I have some sad experience, thousan=
ds of<br>
> timers will slow down my server.<br>
> See my question on stackoverflow:<br>
> <a href=3D"http://stackoverflow.com/questions/22777835/i=
s-boostasio-asyn-read-" target=3D"_blank">http://stackoverflow.com/question=
s/22777835/is-boostasio-asyn-read-</a><br>
> with-timer-a-good-idea<br>
><br>
><br>
><br>
> My question is:<br>
> Why does my async_read blocks?<br>
> Can I use dead line timer in this case?<br>
><br>
><br>
><br>
> Dean Chen<br>
> Best regards<br>
> <a href=3D"http://blog.csdn.net/csfreebird" target=3D"_b=
lank">http://blog.csdn.net/csfreebird</a><br>
><br>
> --------------------------------------------------------=
-----------<br>
> -----------<br>
><br>
> _______________________________________________<br>
> asio-users mailing list<br>
> <a href=3D"mailto:asio-***@lists.sourceforge.net" targ=
et=3D"_blank">asio-***@lists.sourceforge.net</a><br>
> <a href=3D"https://lists.sourceforge.net/lists/listinfo/=
asio-users" target=3D"_blank">https://lists.sourceforge.net/lists/listinfo/=
asio-users</a><br>
> _______________________________________________<br>
> Using Asio? List your project at<br>
> <a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" t=
arget=3D"_blank">http://think-async.com/Asio/WhoIsUsingAsio</a><br>
><br>
><br>
><br>
> ----------------------------------------------------------------------=
--------<br>
> _______________________________________________<br>
> asio-users mailing list<br>
> <a href=3D"mailto:asio-***@lists.sourceforge.net" target=3D"_blank">=
asio-***@lists.sourceforge.net</a><br>
> <a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" ta=
rget=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a>=
<br>
> _______________________________________________<br>
> Using Asio? List your project at<br>
> <a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blan=
k">http://think-async.com/Asio/WhoIsUsingAsio</a><br>
<br>
---------------------------------------------------------------------------=
---<br>
_______________________________________________<br>
asio-users mailing list<br>
<a href=3D"mailto:asio-***@lists.sourceforge.net" target=3D"_blank">asio-=
***@lists.sourceforge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" target=
=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a><br>
_______________________________________________<br>
Using Asio? List your project at<br>
<a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blank">ht=
tp://think-async.com/Asio/WhoIsUsingAsio</a><br>
</div></div></blockquote></div></div></div><br></div>
<br>-----------------------------------------------------------------------=
-------<br>
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***@lists.sourceforge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" target=
=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a><br>
_______________________________________________<br>
Using Asio? List your project at<br>
<a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blank">ht=
tp://think-async.com/Asio/WhoIsUsingAsio</a><br>
<br></blockquote></div><br></div></div></div>
</blockquote></div><br></div></div></div></div><br>------------------------=
------------------------------------------------------<br>
<br>_______________________________________________<br>
asio-users mailing list<br>
<a href=3D"mailto:asio-***@lists.sourceforge.net">asio-***@lists.source=
forge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/asio-users" target=
=3D"_blank">https://lists.sourceforge.net/lists/listinfo/asio-users</a><br>
_______________________________________________<br>
Using Asio? List your project at<br>
<a href=3D"http://think-async.com/Asio/WhoIsUsingAsio" target=3D"_blank">ht=
tp://think-async.com/Asio/WhoIsUsingAsio</a><br>
<br></blockquote></div><br></div>
--089e0158ab5c1aa96d04f60c99c1--