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Thanks Tomasz,
I'm glad you get where I'm coming from, but those issues you mentioned are already taken into consideration by traders. They already don't create scripts that their computers can't handle in real time, and having a per chart refresh ability wouldn't change this.
For the very point you mentioned about scrolling, zooming and drawing, you can't have scripts that take ages to process and you wouldn't practically want any individual script taking more than a couple of seconds. I'm not calling for any changes to this behaviour.
I'm referring to the less extreme and more general situation where you have multiple charts, none of which take more than a second to render, but which combined may take 2 seconds to update. This prohibits getting any use from setting the refresh rate in preferences to 0.
If you're going to allow a 0 refresh rate for realtime, then you also need the ability to delegate less time critical charts to slower updates for it to be of any use.
I may have a script that only takes 100ms to update, but I still don't need it updated any more than once every 5 seconds.
It's about generally not wasting cpu cycles rendering charts that don't need to be, so those cycles can be allocated to more important things.
With requestTimedRefresh, I assume that chart gets put in some form of queue or callback to be updated, can you not just give the ability to also remove this chart from the standard update queue?
Scrolling, zooming and drawing on charts would still cause an update to them just as it does now.
Regards,
Julian.
--- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>
> Hello,
>
> I understand your point, however such idealistic situation (like refresh only once a minute) is somewhat rare
> because of user interaction (zooming/scrolling/drawing object on chart, etc) that all involve refresh.
> Also allowing to have "very complex" indicators to refresh only once a minute
> would inevitably lead to people writing codes that for example need 40 seconds to execute per refresh.
> And that will result in having unresponsive zooming/scrolling/etc.
> The only resonable way to allow very complex codes executing for 10+ seconds
> to do graphic output is to allow rendering static images that don't allow user interaction like scroll/zoom/drawing.
>
> Best regards,
> Tomasz Janeczko
> amibroker.com
> ----- Original Message -----
> From: "Julian" <juliangoodsell@xxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Monday, July 13, 2009 2:09 AM
> Subject: [amibroker] Re: Per Chart Refresh Rates
>
>
> > Hi Tomasz,
> >
> > just to be clear from my side, as this thread has veered off course a little, I'm NOT suggesting running afl scripts without a
> > render, or threading out the afl processing from the GDI rendering.
> > I'm NOT suggesting any changes to the current architecture.
> >
> > I'm asking for the ability to set refresh rates per chart, for which the functionality already seems to be there.
> > Running indicator calculations without rendering is a waste of cpu time, and so is rendering charts that don't need to be.
> > If I have a chart that only needs to be updated every minute, there's no point in AB trying to render it on every tick update.
> >
> > Allowing us to specify at what intervals we want individual charts to update, would save countless wasted cpu time.
> >
> > Regards,
> > Julian.
> >
> > --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@> wrote:
> >>
> >> Hello,
> >>
> >> There is no sense in doing indicator calculation when this calculation
> >> does not lead to actual rendering. That would be waste of CPU.
> >> The purpose of doing indicator calculation is to actually display it (refresh it).
> >> Indicators formulas are here to display something.
> >>
> >> If you want code that does not display anything, you should run it as
> >> automatic-analysis (scan/exploration) code.
> >>
> >> Also AFL formula execution is often much faster than final GDI output,
> >> therefore even if AFL formula was executed in parallel, it would still
> >> face GDI contention because of Windows GDI system-wide lock.
> >>
> >> Only on Windows 7 this system-wide GDI lock is removed and only
> >> there you could see graphic performance scaling
> >>
> >> Again, read the entire article:
> >> http://blogs.msdn.com/e7/archive/2009/04/25/engineering-windows-7-for-graphics-performance.aspx
> >>
> >> Especially figure 4 GDI Concurrency and Scalability
> >> - as you can see in any pre-Win7 systems, GDI does not scale *at all*
> >> with adding threads.
> >>
> >> I can ensure you that I have actually *timed* many scenarios
> >> and what I say is based on actual measurement and not on somebody's "belief".
> >> That was one of the reasons I did not use GDI+ ("improvement" suggested by somebody on this list)
> >> because real-world test revealed that it is 6 times slower than normal GDI.
> >> Microsoft admitted that by the way in their recent demonstration on PDC (prof. dev. conference).
> >>
> >> So, all decisions regarding development of AmiBroker are not based on beliefs but on
> >> hard code profiling evidence.
> >>
> >> Best regards,
> >> Tomasz Janeczko
> >> amibroker.com
> >> ----- Original Message -----
> >> From: "Yofa" <jtoth100@>
> >> To: <amibroker@xxxxxxxxxxxxxxx>
> >> Sent: Sunday, July 12, 2009 9:47 PM
> >> Subject: Re: [amibroker] Per Chart Refresh Rates
> >>
> >>
> >> > Hi Thomas,
> >> >
> >> >> Tomasz wrote in the "Data And PlugIn Speed" thread
> >> >>I may add that the concept of independent rendering from multiple threads
> >> >>although attractive from first look, it inevitably hits the wall of GDI
> >> >>which in all current versions of Windows has
> >> >> single system-wide exclusive global lock, which means that only ONE thread
> >> >> can actually render at one time. This means that adding threads does not
> >> >> give you better performance.
> >> >
> >> >>The truth is that all current releases of Windows are not particularly
> >> >>suited for multi-core/multi-CPU
> >> >>but good news is that Microsoft apparently have given these limitations
> >> >>some thought and
> >> >>many of them are removed in Windows 7.
> >> >
> >> > That is true for rendering only! (Apps main thread is allowed to write the
> >> > GDI device. So rendering is limited to a single thread.)
> >> >
> >> > But indicator calculation (and trading logic) could get executed by any
> >> > threads. Am I right? So doing the calculation on a background thread than
> >> > doing chart painting with the "main" thread would increase processor usage
> >> > and increase chart refresh reate? (I guess we all have dual and quad core
> >> > CPUs...)
> >> >
> >> > How about separating "calculation refresh rate" and "chart refresh rate"? So
> >> > I could request my panel to execute 3 times per sec without chart repaint
> >> > (this could be executed by any threads) and refresh visible chart in every
> >> > 3rd sec (this requires rendering, so calculation is done by a background
> >> > thread, and painting is done by main thread))?
> >> >
> >> > Any thoughts?
> >> >
> >> > Regards,
> >> >
> >> > Y
> >> >
> >> > (I know it is not doable in a day work, but I guess all short
> >> > term/daytraders are having trouble bacause of refresh limitations.)
> >> >
> >> >
> >> > --------------------------------------------------
> >> > From: "Julian" <juliangoodsell@>
> >> > Sent: Sunday, July 12, 2009 8:14 PM
> >> > To: <amibroker@xxxxxxxxxxxxxxx>
> >> > Subject: [amibroker] Per Chart Refresh Rates
> >> >
> >> >> Hi Tomasz, I thought I'd start a new thread on this topic as I think it's
> >> >> an interesting one.
> >> >>
> >> >> Tomasz wrote in the "Data And PlugIn Speed" thread
> >> >>> I may add that the concept of independent rendering from multiple threads
> >> >>> although attractive from first look, it inevitably hits the wall of GDI
> >> >>> which in all current versions of Windows has
> >> >> single system-wide exclusive global lock, which means that only ONE thread
> >> >> can actually render at one time. This means that adding threads does not
> >> >> give you better performance.
> >> >>
> >> >> In response to that Tomasz,
> >> >> you're referring to performance on the basis of multiple charts being
> >> >> rendered per refresh update.
> >> >> E.g. If you have ten charts on screen, and they take a total of 2 seconds
> >> >> to render, then there's little performance gain to be had by threading
> >> >> them because of the GDI lock. That is fine and I get that.
> >> >>
> >> >> But what I'm referring to is the ability to control which charts render
> >> >> when, so that all ten don't have to be updated every refresh.
> >> >> The problem is that in real time mode with the refresh interval set to 0
> >> >> in the preferences, if I have a tick chart that only takes 10ms to update,
> >> >> it's still only going to be rendered every 2 seconds because that's how
> >> >> long the other nine charts take to render, even though I don't need them
> >> >> to be updated multiple times per second, but maybe only once every 5
> >> >> seconds or even every minute.
> >> >>
> >> >> If we could set refresh rates per chart, then you could have time critical
> >> >> tick charts update as fast as possible, and longer timeframe or more time
> >> >> expensive/less critical charts only update every 5 seconds or even longer.
> >> >>
> >> >> By staggering chart updates, traders would have much greater control over
> >> >> performance and not waste so much processing power updating charts that
> >> >> don't need to be. This would trounce any other kind of performance
> >> >> improvement that could be gained by optimizing the rendering engine
> >> >> itself, and would require no threading or any real change to the current
> >> >> architecture that I can see.
> >> >>
> >> >> Moreover, it appears this functionality is already in AB, but just that
> >> >> there's no way for the user to control it.
> >> >> The requestTimedRefresh() function enables you to update only the chart it
> >> >> is applied to, so they can obviously be rendered independently of each
> >> >> other.
> >> >>
> >> >> The problem though is that it is not enforceable. If I specify a refresh
> >> >> interval of 1 in the preferences, and then requestTimedRefresh(10) on a
> >> >> chart, that chart still gets updated every second along with all the
> >> >> others, and then once more after ten seconds.
> >> >>
> >> >> Giving the option to make requestTimedRefresh() enforceable would be one
> >> >> way of enabling this functionality. Perhaps add an enforceable parameter
> >> >> to the function like:
> >> >> requestTimedRefresh(10, onlyvisible=True, enforceable=false).
> >> >> Then if I specify requestTimedRefresh(10, true, true), that chart should
> >> >> only update every 10 seconds, irrespective of what I've set in the
> >> >> preferences.
> >> >>
> >> >> Would this be as easy to implement as I think it is? If so, I think the
> >> >> benefits would be rather large.
> >> >>
> >> >> Jules.
> >> >>
> >> >>
> >> >>
> >> >> ------------------------------------
> >> >>
> >> >> **** IMPORTANT PLEASE READ ****
> >> >> This group is for the discussion between users only.
> >> >> This is *NOT* technical support channel.
> >> >>
> >> >> TO GET TECHNICAL SUPPORT send an e-mail directly to
> >> >> SUPPORT {at} amibroker.com
> >> >>
> >> >> TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
> >> >> http://www.amibroker.com/feedback/
> >> >> (submissions sent via other channels won't be considered)
> >> >>
> >> >> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> >> >> http://www.amibroker.com/devlog/
> >> >>
> >> >> Yahoo! Groups Links
> >> >>
> >> >>
> >> >>
> >> >>
> >> >
> >> >
> >> > ------------------------------------
> >> >
> >> > **** IMPORTANT PLEASE READ ****
> >> > This group is for the discussion between users only.
> >> > This is *NOT* technical support channel.
> >> >
> >> > TO GET TECHNICAL SUPPORT send an e-mail directly to
> >> > SUPPORT {at} amibroker.com
> >> >
> >> > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
> >> > http://www.amibroker.com/feedback/
> >> > (submissions sent via other channels won't be considered)
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> >> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> >> > http://www.amibroker.com/devlog/
> >> >
> >> > Yahoo! Groups Links
> >> >
> >> >
> >> >
> >>
> >
> >
> >
> >
> > ------------------------------------
> >
> > **** IMPORTANT PLEASE READ ****
> > This group is for the discussion between users only.
> > This is *NOT* technical support channel.
> >
> > TO GET TECHNICAL SUPPORT send an e-mail directly to
> > SUPPORT {at} amibroker.com
> >
> > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
> > http://www.amibroker.com/feedback/
> > (submissions sent via other channels won't be considered)
> >
> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> > http://www.amibroker.com/devlog/
> >
> > Yahoo! Groups Links
> >
> >
> >
>
------------------------------------
**** IMPORTANT PLEASE READ ****
This group is for the discussion between users only.
This is *NOT* technical support channel.
TO GET TECHNICAL SUPPORT send an e-mail directly to
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TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
http://www.amibroker.com/feedback/
(submissions sent via other channels won't be considered)
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