Re: responsive threading

Are you sure that waiting for vsync gives out time? This depends on driver 
and API used, but usually, it is just a busy waiting loop. IIRC, we had to 
jump through some nasty hoops to make our swaps actually yield time to our 
loading thread. YMMV.

Alen


----- Original Message ----- 
From: "Andras Balogh" <[email protected]>
To: "Alen Ladavac" <[email protected]>
Sent: Sunday, July 31, 2005 14:51
Subject: Re: [GD-General] responsive threading


>I do wait in the higher priority thread. Actually, this thread spends
> 90% of the frame time waiting (for vsync)! So the idle thread has
> plenty of time, and despite the lower priority, it gets a lot more
> CPU, than my primary thread!
>
>
> Saturday, July 30, 2005, 6:40:15 AM, you wrote:
>
>> If the higher priority thread never ever waits, windows go out of their 
>> way
>> and give some time to the lower priority thread in that case. Search
>> "priority inversion" in MSDN. Perhaps sleeping a bit once in a while in 
>> the
>> rendering thread to give a slice to the processing thread, might help you
>> keep the situation under control.
>
>> HTH,
>> Alen
>
>> ----- Original Message ----- 
>> From: "Andras Balogh" <[email protected]>
>> To: <[email protected]>
>> Sent: Friday, July 29, 2005 21:22
>> Subject: Re: [GD-General] responsive threading
>
>
>>> I've tried setting the primary thread to time critical and the other
>>> thread to idle (and I also disabled it's priority boost), and it does 
>>> help
>>> quite a bit, but I'm still seeing some small glitches. I'm not saying 
>>> it's
>>> bad, it's pretty good actually, and people are so used to bad framerates
>>> nowadays that I'm sure they wouldn't complain a tiny bit. I do admit 
>>> that
>>> I'm a bit on the perfectionist side on this one :)
>>>
>>> I have tried setting the process priority class to real-time too, but in
>>> that case my "idle" priority thread won't be really idle anymore,
>>> actually, the hiccups get much worse. I guess I could run in a separate
>>> process even, but that's really overkill.
>>>
>>>
>>> Andras
>>>
>>> Brian Hook wrote:
>>>> At the risk of asking the obvious, have you also set your primary 
>>>> thread
>>>> to run at the highest priority (REAL_TIME or whatever it's called on
>>>> Windows)?
>>>>
>>>> I run audio mixing in a separate thread and by setting things
>>>> appropriately (and sleeping when necessary) I never get hiccups.
>>>>
>>>> Brian
>>>>
>>>> On Fri, 29 Jul 2005 14:35:21 -0600, Andras Balogh wrote:
>>>>
>>>>>I'm loading lots of "small" (avg. 1k x 1k) regions from lots of
>>>>>huge (5GB+) wavelet compressed images. I'm using a 3rd party
>>>>>library to do this (ECW), so I don't know the implementation
>>>>>details, but I could look at the code, if I knew what to look for..
>>>>>
>>>>>
>>>>>Andras
>>>>>
>>>>>
>>>>>Mat Noguchi (BUNGIE) wrote:
>>>>>
>>>>>>What else are you doing on the IO thread to make it eat up so
>>>>>>much CPU time?
>>>>>>
>>>>>>MSN
>>>>>>-----Original Message-----
>>>>>>From: [email protected]
>>>>>>[mailto:[email protected]] On
>>>>>>Behalf Of Andras Balogh Sent: Friday, July 29, 2005 10:44 AM To:
>>>>>>[email protected] Subject: [GD-General]
>>>>>>responsive threading
>>>>>>
>>>>>>I'm developing a graphics application, that I want to be very
>>>>>>responsive, very smooth, all the time! The rendering is pretty
>>>>>>simple, the framerate is high and stable, so I just lock to
>>>>>>vsync, and everything moves beautifully smooth! The CPU usage for
>>>>>>this thread is always below 10%.
>>>>>>
>>>>>>However, I also have another thread, that has to do some heavy
>>>>>>work. This thread does tons of IO operations, and also makes the
>>>>>>CPU sweat!
>>>>>>
>>>>>>There is no synchronization between the two threads, so they
>>>>>>should be able to run independently. Still, I'm experienceing
>>>>>>sudden spikes in the
>>>>>>
>>>>>>framerate, when the second thread is really hammering. What could
>>>>>>be the
>>>>>>
>>>>>>reason for this? Is it possible to do something about it, to
>>>>>>regain the continuous framerate? I'm really not interested in the
>>>>>>performance of the second thread, I just want my first thread to
>>>>>>run as smooth as possible! I've tried lowering the priority for
>>>>>>the second thread, and it
>>>>>>
>>>>>>does help, but there are still some spikes. Is it possible that
>>>>>>it's Windows itself doing some operations at higher priority,
>>>>>>like memory management, IO stuff, and the likes?
>>>>>>
>>>>>>Thanks,
>>>>>>
>>>>>>
>>>>>>Andras
>
>
>
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