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Sounds like a good idea to me.
Best regards,
Byron Campen
Byron Campen wrote:So, maybe on win32 we need to have something call getTimeMs() every minute? A heartbeat timer of some sort?You could be even more clever about it than that. Inserting a timer immediately before and after the rollover should get you there. That way, you have two timers every 49 days, instead of one timer every minute. :)UInt64 timer1Time = 0x00000000FFFFFFF0ui64 | (Timer::getTimeMs() & 0xFFFFFFFF00000000ui64);UInt64 timer2Time = timer1 + 33;Then, all you need is a new Timer constructor that takes an absolute time instead of a relative one./aBest regards, Byron CampenTo qualify things further, though: in order for this bug to be triggered, you would need to have no calls to "Timer::getTimeMs()" for over two minutes (131.07 seconds, to be more precise) as the 49.7-day boundary rolls around. In a normally operating SIP stack, the chances of this happening seem vanishingly small.So, it's a corner case on top of a corner case. And it only happens on WIN32 systems./a Byron Campen wrote:Ok, so this is in the "much more serious" category. I would not be comfortable leaving this be.Best regards, Byron CampenByron Campen wrote:Let's say one of these timers is at the top of the heap, and whatever error you're thinking about happens. Are you saying that not only will that timer be 49 days late, but everything else in the heap will be too?Not new timers. But, if we miss the rollover, then everything in the heap at that time will instantaneously appear to be 49.7 days later than their original expiration time. New timers will be inserted in the heap just fine (ahead of the "lost" timers), and expire correctly.The behavior would be similar to using our current stack and setting the system time to be 49 days in the past while timers are pending./aBest regards, Byron CampenTechnically, they won't be "lost" as much as "over 49 days late." From a SIP protocol perspective, 49 days is long enough to consider the timer lost for all practical purposes./a Byron Campen wrote:I can see how we would miss a roll-over with low timer activity, but I am not sure what you mean by "lose timers". If we have lost a timer from a timer heap, that implies the heap is now broken, because that is the only way to "lose" anything. So this is either much more serious, or much less serious than you have stated.Best regards, Byron CampenScott (and any other Windows developers on the list):The Windows 49.7-day rollover fix in this patch uses heuristics to handle the rollover in an efficient manner -- you can actually lose timers if you have relatively low timer activity and a multi-minute timer running when the tick count rolls over. The chances of this happening are, admittedly, vanishingly small (especially in normal SIP usage). In any case, you might want to give that code a quick review to ensure that you're comfortable with it.Also, I think it's safe to say that it's difficult to test the correctness of the code, as step one of any such test plan necessarily involves something like: "boot a Windows machine and wait 49.6 days." Make sure you're comfortable with that fact as well./a Alexander wrote:Hi Here is a patch to use monotonic clock. It is 3 modified files from reSIProcate 1.4. Attached files have Windows (CLRF) eof-style. Windows ======= GetTickCount() with 16 ms inaccuracy used.It is very simple to change it to timeGetTime() etc with 1 ms accuracy, but it will require init/fini calls on application level and linkingwith Winmm.lib Tested on Windows XP SP2, compiled with VS7.1 Not tested on Windows CE Linux =====If monotonic clock is not available (compile time and runtime) it willfall back to gettimeofday()I am not familiar with reSIProcate build system so I use workaround toavoid linking with librt: syscall( __NR_clock_gettime, ... ) instead of clock_gettime(...) IMHO it may not work on other POSIX compliant platforms. Pass only some basic tests on my Linux PC (2.6.18 kernel) Any feedbacks appreciated. Regards Alexander Altshuler Xeepe team http://xeepe.com ------------------------------------------------------------------------ _______________________________________________ resiprocate-devel mailing list resiprocate-devel@xxxxxxxxxxxxxxx https://list.resiprocate.org/mailman/listinfo/resiprocate-devel_______________________________________________ resiprocate-devel mailing list resiprocate-devel@xxxxxxxxxxxxxxxhttps://list.resiprocate.org/mailman/listinfo/resiprocate- devel
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