[Mono-dev] Busy loop in mono

[Zoltan Varga]

Hi,

  I cannot reproduce this with mono master on a debian amd64 system.

               Zoltan


On Fri, Jan 31, 2014 at 4:03 PM, Jonathan Gagnon <
jonathan.gagnon at croesus.com> wrote:

> It seems to be related to thread pool threads. I wrote a simple program
> that reproduces the problem:
>
> using System.Threading;
> using System.Threading.Tasks;
>
> namespace MultiThreadApp
> {
> class Program
> {
> static ManualResetEvent evnt = new ManualResetEvent(false);
>
> static void Main(string[] args)
> {
> for (int i = 0; i < 50; ++i)
>  {
> Task task = new Task(DoNothing);
> task.Start();
>  }
>
> evnt.WaitOne();
> }
>
>  static void DoNothing()
> {
> Thread.Sleep(1000);
>  }
> }
> }
>
>
>
>
>
>
> On Fri, Jan 31, 2014 at 2:31 PM, Jonathan Gagnon <
> jonathan.gagnon at croesus.com> wrote:
>
>> It seems like this bug https://bugzilla.novell.com/show_bug.cgi?id=379602in mono 3.2.5.
>>
>> I was fixed in mono 2.4 but it seems to have reappeared since then
>> because my process is using CPU at doing nothing and I noticed it gets
>> worse if I add threads (even if they do nothing). When I use strace on a
>> process running with mono 3.2.5, I get a similar output :
>>
>> futex(0x9ce6520, FUTEX_WAIT, 81061, {0, 999009600}) = -1 ETIMEDOUT
>> (Connection timed out)
>> time(NULL)                              = 1391196463
>> futex(0x9ce6504, FUTEX_WAKE, 1)         = 0
>> gettimeofday({1391196463, 363628}, NULL) = 0
>> gettimeofday({1391196463, 363707}, NULL) = 0
>> time(NULL)                              = 1391196463
>> gettimeofday({1391196463, 363848}, NULL) = 0
>> time(NULL)                              = 1391196463
>> time(NULL)                              = 1391196463
>> clock_gettime(CLOCK_REALTIME, {1391196463, 364038031}) = 0
>> futex(0x9ce6520, FUTEX_WAIT, 81063, {0, 998961969}) = -1 ETIMEDOUT
>> (Connection timed out)
>> time(NULL)                              = 1391196464
>> futex(0x9ce6504, FUTEX_WAKE, 1)         = 0
>> gettimeofday({1391196464, 363500}, NULL) = 0
>> gettimeofday({1391196464, 363597}, NULL) = 0
>> time(NULL)                              = 1391196464
>> gettimeofday({1391196464, 363713}, NULL) = 0
>> time(NULL)                              = 1391196464
>> time(NULL)                              = 1391196464
>> clock_gettime(CLOCK_REALTIME, {1391196464, 363903927}) = 0
>>
>> The same process doesn't use any cpu time when running on .NET.
>>
>> Any idea what could cause this problem.  Has anyone else noticed this
>> problem?
>>
>> Jonathan
>>
>
>
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