[Boost-bugs] [Boost C++ Libraries] #9662: High CPU usage for steady_clock waitable timer on Windows (integer overflow problem)

Subject: [Boost-bugs] [Boost C++ Libraries] #9662: High CPU usage for steady_clock waitable timer on Windows (integer overflow problem)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-02-12 06:52:35

#9662: High CPU usage for steady_clock waitable timer on Windows (integer overflow
problem)
-------------------------------------------------+-------------------------
 Reporter:  wyatt@…                              |      Owner:
     Type:  Bugs                                 |  chris_kohlhoff
Milestone:  To Be Determined                     |     Status:  new
  Version:  Boost 1.55.0                         |  Component:  asio
 Keywords:  asio, SetWaitableTimer,              |   Severity:  Problem
  basic_waitable_timer, steady_clock             |
-------------------------------------------------+-------------------------
 Hey Guys & Girls,

 I've tracked down a bug in your waitable timer implementation on Windows.
 Specifically the update_timeout() function in
 "boost/asio/detail/impl/win_iocp_io_service.ipp". More specifically the
 SetWaitableTimer() call in that function for certain "timeout_usec"
 values.

 Specifically, for certain large "wait values" the current implementation
 thrashes the CPU using up nearly all the CPU time on a "core" of the
 processor. Obviously that's not ideal.

 I haven't tracked down the exact place where things go wrong, nor have I
 written a patch. If I get some free time in a month or 2 I might do it if
 no one else wants to pick it up.

 Here's how you can reproduce it. (If you want I can put together a full
 example for you)






 {{{
 typedef boost::asio::basic_waitable_timer<boost::chrono::steady_clock>
 monotonic_timer;



 monotonic_timer buggy_timer_(io_service_);

 buggy_timer_.expires_from_now(boost::chrono::seconds(86400));
 buggy_timer_.async_wait(boost::bind(&server::callback_function, this,
 boost::asio::placeholders::error));

 io_service_.run()
 }}}




 The problem lies with this:

 {{{
 boost::chrono::seconds(86400)
 }}}


 If you use a value half as large (43200 seconds) then the program uses
 normal CPU levels (i.e. around 0% CPU). Obviously we've got an integer
 overflow problem and faulty logic. As I said, I believe it's in the
 update_timeout() function in
 "boost/asio/detail/impl/win_iocp_io_service.ipp"


 If you need more information just ask and I'll be glad to provide it.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9662>
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