On Apr 11, 2013, at 2:39 PM, David Holmes wrote:
> On 11/04/2013 10:30 PM, Rickard Bäckman wrote:
>> David,
>>
>> On Apr 11, 2013, at 2:15 PM, David Holmes wrote:
>>
>>> Rickard,
>>> On 11/04/2013 9:51 PM, Rickard Bäckman wrote:
>>>> Hi all,
>>>>
>>>> can I please have reviews for this change.
>>>>
>>>> In the current implementation do_suspend uses spin loops to wait until a
>>>> thread has been suspended. I would like to change that to use semaphores
>>>> to reduce CPU usage and also make it easier to have a deterministic
>>>> timeout. Since we are posting to the semaphore in the signal handler we
>>>> can't use pthread_semaphore since it isn't async safe, which is why all
>>>> implementations uses low-level os-specific semaphore constructs.
>>>
>>> POSIX Semaphore sem_post() is async-signal safe:
>>
>> Yes, and they are used in the implementation on Linux and BSD. Solaris uses
>> the sema_{post,wait,…} (since that was we were already using for other
>> things) and on Mac we use semaphore_{signal, wait, …}
>
> So what did you mean about pthread_semaphore (what is that anyway?) ??
Never mind, pthread condition variables.
>
> I really, really, really don't like seeing three versions of this class :(
> Can't BSD and Linux at least share a POSIX version? (And I wonder if we can
> actually mix-n-match UI threads on Solaris with POSIX semaphores on Solaris?)
I don't like it either, our OS code isn't really helpful when it comes do
reusing things :) Not sure how I would layout things to make them only
available on BSD (Not Mac) and Linux. I guess os_posix.hpp with lots of
#ifdefs, but I'm not sure I"m feeling that happy about that.
/R
>
> David
>
>> /R
>>
>>>
>>> http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04
>>>
>>> David
>>> -----
>>>
>>>> Bug: http://bugs.sun.com/view_bug.do?bug_id=8011882
>>>> Webrev: http://cr.openjdk.java.net/~rbackman/8011882/
>>>>
>>>> Thanks
>>>> /R
>>>>
>>
