LiveCode Forums.

Hi all,

I was just wondering if there's a profiler available for LC to help spot coed execution bottlenecks and the like? Looking at my current in-development app on my iPad it seems a bit sluggish and I'd like to see where the slowdown is occurring.

If such a thing doesn't exist, does anyone have any handy hints for identifying bottlenecks and choke points?

Regards

Chris

Hi.

Bottlenecks are usually classified at different levels. For example, running a repeat loop where a field is updated (or data extracted from) each iteration may be considered a "Level 1" issue. Not optimizing, say, where an array might do the work of mighty swathes of code could be called "Level 2".

Not employing the old adage, "...a little analysis is worth a million lines of code" might be called "Level 3".

But after all that nonsense, using small embedded timing routines, you know, getting the ticks and then seeing how many ticks have passed after a segment of code executes, is usually how I do it.

Craig Newman

Open the Message Watcher and run the script. You will see every message and handler that executes. Next to each one is the time in milliseconds between the end of the previous line and the completion of the current one.

The Message Watcher can become overrun with too much info you may not want. You can use the Suppress button to remove things you aren't interested in.

Have a stack 4W_UmbrellaMan.rev that does what OP wishes and has a good filter, author: community manager RG.
Sadly not fully up-to-date (and opens only in commercial IDE).

UmbrellaMan was replaced with a newer version that has a more sensible name some years ago (I still like to have fun with names but few know the old Glenn Miller song that was named after or why I'd choose it at all, and as I get older I try to keep in mind that other people have things do to beyond trying to sort their way through even more obscure names than the ones I eventually settle on, a lesson some Linux projects could learn from <g>) :
http://fourthworld.net/revnet/devolutio ... ivecode.gz

That version is unlocked and is maintained in LC v6.x, so it's compatible with LC Commercial, Enterprise, Indy, Business, and Community Editions from v5.5 through the present.

I never claim compatibility with any Developer Preview edition of LiveCode, because any build prior to Release Candidate is subject to changes which may affect a plugin. Still, I just ran Flight Recorder in LC 8.0 DP 11 and it seems to run well.

I should note that the profiling info shown in Flight Recorder's "MS" column (for "Milliseconds") are approximations made even less reliable by the method in which they're gathered. The main purpose of Flight Recorder is to trap messages in a way more tailorable than LiveCode's, with greater clarity than LiveCode's provided by the indenting which reflects the calling chain. The profiling was very much an afterthought, and even now not much of a priority for myself; I find that even the loose approximations it provides is more than enough for me to find opportunities for optimization.

All that said, the indenting alone will likely be as helpful as the profiling for finding bottlenecks, because redundant calls are easily identified but any non-redundant calls may take a seemingly large amount of time but you still won't know why they're taking so much time, whether such calls are actually good candidates for optimization or just things that inherently take longer.

A few years ago I started sketching out another tool I was calling ScriptDoctor, which would analyze scripts and not only find things that take longer but also attempt to discern why they're taking longer, and offer suggestions for optimization.

I've set that aside, however, mostly due to client projects keeping me so busy but also due to its limited utility: it would have a low ROI if positive at all, because:
a) the more time you spend with LiveCode the more you pick up habits that make your code more performant, so the value of the tool would only decrease over time;
b) some aspects of performance change between versions as features are added and refined, so a bottleneck identified through yesterday's rules may not apply tomorrow;
c) the best - and most enjoyable - way to optimize performance is to post code here for review and revision.

One of my favorite examples of c) is a wonderful discussion here titled "How to Speed Up This Code?":
http://forums.livecode.com/viewtopic.php?f=8&t=24945

A good read for a wide range of performance tips, and for seeing the benefits of getting lots of eyeballs on a problem. Many people contributed to that example, each bringing their own insights along the way, and ultimately a process that had taken 9 minutes was reduced to a few milliseconds.

In short, Chris, this is all just a long-winded way of saying that while profiling tools for LC are currently somewhat limited, the nature of such tools is always a bit limited anyway, so if you're in a position to post a portion of the code you're concerned about I'll bet we can explore it to boost its performance by perhaps as much as an order of magnitude or more. And along the way others will benefit from the discussion as well, and most importantly we'll have not only faster code, but an understanding of why it's faster.

I built a timer handler and I just use it throughout my app where i would want to analyze performance. Give each timed event a different name and you should be able to easily see whats taking so long. its a much simpler solution than a profiler per se...but a ms count is quite telling as well.

One thing i've learned from using it is that LC engine is very fast at most things..... Haven't done mobile dev though, so it could be different there.