Difference between revisions of "Profiling"

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Gideros comes with an integrated native lua profiler.
+
The Ultimate Guide to Gideros Studio
  
For those who don't know what is a code profiler, it is a tool that measure effectiveness of the code and outputs statistics about the CPU usage: number of times each function was called, how much time it took to execute, and where was it called from.  
+
__TOC__
 +
 
 +
== Profiling ==
 +
Gideros comes with an integrated native Lua profiler.
 +
 
 +
For those who don't know what is a code profiler, it is a tool that measures code effectiveness and outputs statistics about the CPU usage: number of times each function was called, how much time it took to execute, where it was called from.
  
 
Gideros provides two means of enabling profiling:
 
Gideros provides two means of enabling profiling:
* By launching a profiling session directly through 'Profile' menu item or toolbar icon from Gideros Studio
+
*by launching a profiling session directly through 'Profile' menu item or toolbar icon from Gideros Studio
* By calling Core.profiler* API from lua
+
*by calling Core.profiler* API from Lua
  
 
In the former case, Gideros Studio will display the profiling results when the stop button is hit in Gideros Studio toolbar. In the latter, you have to handle profiling data collection and display by yourself.
 
In the former case, Gideros Studio will display the profiling results when the stop button is hit in Gideros Studio toolbar. In the latter, you have to handle profiling data collection and display by yourself.
  
'''Note that even if you started profiling through Gideros Studio, you can still use Core.profilier* API within your code.'''
+
'''Note that even if you started profiling through Gideros Studio, you can still use Core.profiler* API within your code.'''
Gideros profiling API available from lua is:
 
* Core.profilerStart(), which instructs gideros start collecting profiling data
 
* Core.profilerStop(), which pause collecting
 
* Core.profilerReset(), which clears collected data
 
* Core.profilerReport(), which returns a table containing collected profiling data
 
 
 
 
 
;Enough said about the internals, let's see how profiling can help us!
 
  
So suppose you are running the following code:
+
Available Gideros profiling API:
 +
*Core.profilerStart(), which instructs Gideros to start collecting profiling data
 +
*Core.profilerStop(), which pause collecting
 +
*Core.profilerReset(), which clears collected data
 +
*Core.profilerReport(), which returns a table containing collected profiling data
  
 +
== Example ==
 +
Let's see how profiling can help us, suppose you are running the following code:
 
<source lang="lua">
 
<source lang="lua">
 
local function myFunction(a)
 
local function myFunction(a)
Line 28: Line 31:
 
</source>
 
</source>
  
and happen to use it very often. It is far from being optimized (on purpose, right) and turns out to be slow, but how can we do better ?
+
and happen to use it very often. It is far from being optimized (on purpose, right) and turns out to be slow. How can we do better?
 
 
Lets ask the profiler how does it run, say we want to run it 100000 times:
 
  
 +
Let's ask the profiler how does the code perform, say we want to run it 100,000 times:
 
<source lang="lua">
 
<source lang="lua">
 
for i=1,100000 do myFunction(i) end
 
for i=1,100000 do myFunction(i) end
Line 37: Line 39:
  
 
This code outputs:
 
This code outputs:
<table><tr class="theader">
+
<table>
<th class="fnum">#</th><th class="ftime">Time</th><th class="fpct">Ratio</th><th class="fcount">Count</th><th class="fname">Function</th><th class="floc">Location</th></tr>
+
<tr class="theader">
 +
<th class="fnum">#</th>
 +
<th class="ftime">Time</th>
 +
<th class="fpct">Ratio</th>
 +
<th class="fcount">Count</th>
 +
<th class="fname">Function</th>
 +
<th class="floc">Location</th>
 +
</tr>
 
<tr class="current"><td><a id="f1">[1]</a></td><td>  423</td><td>  0%</td><td>    1</td><td>callFile</td><td>=[C] 00421900(callFile)</td></tr>
 
<tr class="current"><td><a id="f1">[1]</a></td><td>  423</td><td>  0%</td><td>    1</td><td>callFile</td><td>=[C] 00421900(callFile)</td></tr>
 
<tr class="callee"><td></td><td>  423</td><td>100%</td><td>    1</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FAC64</td></tr>
 
<tr class="callee"><td></td><td>  423</td><td>100%</td><td>    1</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FAC64</td></tr>
Line 63: Line 72:
 
</table>
 
</table>
  
This is a list of all functions ran by the code sorted by CPU usage (highest first). The first chunk is about a function called ''callFile''. It is an internal Gideros Function which loads each lua file. In our case it was used to launch main.lua, which corresponds to block [2]. But let's focus on our function ''myFunction'', we can see it is covered by block [3]:
+
 
<table><tr class="theader">
+
This is a list of all functions ran by the code sorted by CPU usage (highest first). The first chunk is about a function called ''callFile''. It is an internal Gideros Function which loads each lua file. In our case it was used to launch main.lua, which corresponds to block [2].
<th class="fnum">#</th><th class="ftime">Time</th><th class="fpct">Ratio</th><th class="fcount">Count</th><th class="fname">Function</th><th class="floc">Location</th></tr>
+
 
 +
Let's focus on our function ''myFunction'', we can see it is covered by block [3]:
 +
<table>
 +
<tr class="theader">
 +
<th class="fnum">#</th>
 +
<th class="ftime">Time</th>
 +
<th class="fpct">Ratio</th>
 +
<th class="fcount">Count</th>
 +
<th class="fname">Function</th>
 +
<th class="floc">Location</th>
 +
</tr>
 
<tr class="caller"><td></td><td>  405</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FAC64</td></tr>
 
<tr class="caller"><td></td><td>  405</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FAC64</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>  405</td><td> 35%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FD87C</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>  405</td><td> 35%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FD87C</td></tr>
 
<tr class="callee"><td></td><td>  265</td><td> 65%</td><td>200000</td><td><a href="#f4">c</a></td><td>@main.lua:27:033FC328</td></tr>
 
<tr class="callee"><td></td><td>  265</td><td> 65%</td><td>200000</td><td><a href="#f4">c</a></td><td>@main.lua:27:033FC328</td></tr>
 
</table>
 
</table>
So the function ''myFunction'' took, as expected, most of the processing time. Figures tell us that it was called 100000 times and consumed 405ms on CPU. We also learn that it was called from an unnamed function located at main.lua:0, which is the toplevel lua code of main.lua file, and that all the time (100%) spent in myFunction was due to being called by main.lua.
+
 
More interesting, we discover that 65% of the time (265ms) was spent in calls to function ''c'' located at main.lua:27, and that c was called 200000 times, twice per call.
+
 
 +
So the function ''myFunction'' took, as expected, most of the processing time. Figures tell us that it was called 100,000 times and consumed 405ms on CPU. We also learn that it was called from an unnamed function located at main.lua:0, which is the toplevel lua code of main.lua file, and that all the time (100%) spent in myFunction was due to being called by main.lua.
 +
 
 +
More interestingly, we discover that 65% of the time (265ms) was spent in calls to function ''c'' located at main.lua:27, and that c was called 200,000 times, twice per call.
  
 
The next chunk is about function ''c'': 40% of the time of ''c'' was spent in math.cos(), and 60% in the function itself.
 
The next chunk is about function ''c'': 40% of the time of ''c'' was spent in math.cos(), and 60% in the function itself.
  
We now that calling a function is expensive, and that ''c'' function is rather simple. Lets try to inline it:
+
We know that calling a function is expensive, and that ''c'' function is rather simple. Lets try to inline it:
 
 
 
<source lang="lua">
 
<source lang="lua">
 
local function myFunction(a)
 
local function myFunction(a)
Line 84: Line 105:
  
 
Now profiler report looks like this: (truncated)
 
Now profiler report looks like this: (truncated)
<table><tr class="theader">
+
<table>
<th class="fnum">#</th><th class="ftime">Time</th><th class="fpct">Ratio</th><th class="fcount">Count</th><th class="fname">Function</th><th class="floc">Location</th></tr>
+
<tr class="theader">
 +
<th class="fnum">#</th>
 +
<th class="ftime">Time</th>
 +
<th class="fpct">Ratio</th>
 +
<th class="fcount">Count</th>
 +
<th class="fname">Function</th>
 +
<th class="floc">Location</th>
 +
</tr>
 
<tr class="caller"><td></td><td>    65</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FC4FC</td></tr>
 
<tr class="caller"><td></td><td>    65</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FC4FC</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>    65</td><td> 73%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FB670</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>    65</td><td> 73%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FB670</td></tr>
Line 93: Line 121:
 
<tr class="current"><td><a id="f4">[4]</a></td><td>    17</td><td>100%</td><td>200000</td><td>cos</td><td>=[C] 6E416FE0(cos)</td></tr>
 
<tr class="current"><td><a id="f4">[4]</a></td><td>    17</td><td>100%</td><td>200000</td><td>cos</td><td>=[C] 6E416FE0(cos)</td></tr>
 
</table>
 
</table>
 +
  
 
''myFunction'' is already faster: 65ms now where we had 405ms before.
 
''myFunction'' is already faster: 65ms now where we had 405ms before.
 +
 
We still call math.cos two times. Lets make it (and math.pi) local.
 
We still call math.cos two times. Lets make it (and math.pi) local.
 
 
<source lang="lua">
 
<source lang="lua">
 
local function myFunction(a)
 
local function myFunction(a)
Line 105: Line 134:
 
</source>
 
</source>
  
and profiler report:
+
Now the profiler report:
 
+
<table>
<table><tr class="theader">
+
<tr class="theader">
<th class="fnum">#</th><th class="ftime">Time</th><th class="fpct">Ratio</th><th class="fcount">Count</th><th class="fname">Function</th><th class="floc">Location</th></tr>
+
<th class="fnum">#</th>
 +
<th class="ftime">Time</th>
 +
<th class="fpct">Ratio</th>
 +
<th class="fcount">Count</th>
 +
<th class="fname">Function</th>
 +
<th class="floc">Location</th>
 +
</tr>
 
<tr class="caller"><td></td><td>    60</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FAC64</td></tr>
 
<tr class="caller"><td></td><td>    60</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FAC64</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>    60</td><td> 71%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FD1E8</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>    60</td><td> 71%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FD1E8</td></tr>
 
<tr class="callee"><td></td><td>    17</td><td> 29%</td><td>200000</td><td><a href="#f4">cos</a></td><td>=[C] 6E416FE0(cos)</td></tr>
 
<tr class="callee"><td></td><td>    17</td><td> 29%</td><td>200000</td><td><a href="#f4">cos</a></td><td>=[C] 6E416FE0(cos)</td></tr>
 
</table>
 
</table>
 +
  
 
We saved time in ''myFunction'', while ''cos()'' took the same time.
 
We saved time in ''myFunction'', while ''cos()'' took the same time.
  
What if we use new gideros deg to rad operator instead of math.pi and 180 constant ?
+
What if we use Gideros deg to rad operator instead of math.pi and 180 constant?
 
 
 
<source lang="lua">
 
<source lang="lua">
 
local function myFunction(a)
 
local function myFunction(a)
Line 125: Line 160:
 
</source>
 
</source>
  
and profiler report:
+
Profiler report:
 
+
<table>
<table><tr class="theader">
+
<tr class="theader">
<th class="fnum">#</th><th class="ftime">Time</th><th class="fpct">Ratio</th><th class="fcount">Count</th><th class="fname">Function</th><th class="floc">Location</th></tr>
+
<th class="fnum">#</th>
 +
<th class="ftime">Time</th>
 +
<th class="fpct">Ratio</th>
 +
<th class="fcount">Count</th>
 +
<th class="fname">Function</th>
 +
<th class="floc">Location</th>
 +
</tr>
 
<tr class="caller"><td></td><td>    57</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FC4FC</td></tr>
 
<tr class="caller"><td></td><td>    57</td><td>100%</td><td>100000</td><td><a href="#f2">Unknown</a></td><td>@main.lua:0:033FC4FC</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>    57</td><td> 69%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FB9DC</td></tr>
 
<tr class="current"><td><a id="f3">[3]</a></td><td>    57</td><td> 69%</td><td>100000</td><td>myFunction</td><td>@main.lua:26:033FB9DC</td></tr>
 
<tr class="callee"><td></td><td>    17</td><td> 31%</td><td>200000</td><td><a href="#f4">cos</a></td><td>=[C] 6E416FE0(cos)</td></tr>
 
<tr class="callee"><td></td><td>    17</td><td> 31%</td><td>200000</td><td><a href="#f4">cos</a></td><td>=[C] 6E416FE0(cos)</td></tr>
 
</table>
 
</table>
 +
  
 
We saved a few more precious milliseconds!
 
We saved a few more precious milliseconds!
  
As you can see, the profiler is an useful tool to spot CPU bottlenecks in your app, and some times a few minor changes in the code can make big differences: avoid table access, avoid function calls, avoid duplicate computations.
+
== Conclusion ==
 +
As you can see, the profiler is a useful tool to spot CPU bottlenecks in your app.
 +
 
 +
Sometimes a few minor changes in the code can make a big difference. In general, avoid table access, avoid function calls, avoid duplicate computations.
 +
 
 +
 
 +
'''PREV.''': [[File_system]]<br/>
 +
'''END'''

Revision as of 18:41, 10 May 2020

The Ultimate Guide to Gideros Studio

Profiling

Gideros comes with an integrated native Lua profiler.

For those who don't know what is a code profiler, it is a tool that measures code effectiveness and outputs statistics about the CPU usage: number of times each function was called, how much time it took to execute, where it was called from.

Gideros provides two means of enabling profiling:

  • by launching a profiling session directly through 'Profile' menu item or toolbar icon from Gideros Studio
  • by calling Core.profiler* API from Lua

In the former case, Gideros Studio will display the profiling results when the stop button is hit in Gideros Studio toolbar. In the latter, you have to handle profiling data collection and display by yourself.

Note that even if you started profiling through Gideros Studio, you can still use Core.profiler* API within your code.

Available Gideros profiling API:

  • Core.profilerStart(), which instructs Gideros to start collecting profiling data
  • Core.profilerStop(), which pause collecting
  • Core.profilerReset(), which clears collected data
  • Core.profilerReport(), which returns a table containing collected profiling data

Example

Let's see how profiling can help us, suppose you are running the following code:

local function myFunction(a)
	local function c(a) return math.cos(a*math.pi/180) end
	return c(a)+c(a+1)
end

and happen to use it very often. It is far from being optimized (on purpose, right) and turns out to be slow. How can we do better?

Let's ask the profiler how does the code perform, say we want to run it 100,000 times:

for i=1,100000 do myFunction(i) end

This code outputs:

# Time Ratio Count Function Location
<a id="f1">[1]</a> 423 0% 1callFile=[C] 00421900(callFile)
423100% 1<a href="#f2">Unknown</a>@main.lua:0:033FAC64
 
423100% 1<a href="#f1">callFile</a>=[C] 00421900(callFile)
<a id="f2">[2]</a> 423 4% 1Unknown@main.lua:0:033FAC64
405 96%100000<a href="#f3">myFunction</a>@main.lua:26:033FD87C
 
405100%100000<a href="#f2">Unknown</a>@main.lua:0:033FAC64
<a id="f3">[3]</a> 405 35%100000myFunction@main.lua:26:033FD87C
265 65%200000<a href="#f4">c</a>@main.lua:27:033FC328
 
265100%200000<a href="#f3">myFunction</a>@main.lua:26:033FD87C
<a id="f4">[4]</a> 265 60%200000c@main.lua:27:033FC328
107 40%200000<a href="#f5">cos</a>=[C] 6E416FE0(cos)
 
107100%200000<a href="#f4">c</a>@main.lua:27:033FC328
<a id="f5">[5]</a> 107100%200000cos=[C] 6E416FE0(cos)
 
<a id="f6">[6]</a> 2100% 313gideros_enterFrame=[C] 00423050(gideros_enterFrame)
 
<a id="f7">[7]</a> 0100% 1broadcastEvent=[C] 00423340(broadcastEvent)
 


This is a list of all functions ran by the code sorted by CPU usage (highest first). The first chunk is about a function called callFile. It is an internal Gideros Function which loads each lua file. In our case it was used to launch main.lua, which corresponds to block [2].

Let's focus on our function myFunction, we can see it is covered by block [3]:

# Time Ratio Count Function Location
405100%100000<a href="#f2">Unknown</a>@main.lua:0:033FAC64
<a id="f3">[3]</a> 405 35%100000myFunction@main.lua:26:033FD87C
265 65%200000<a href="#f4">c</a>@main.lua:27:033FC328


So the function myFunction took, as expected, most of the processing time. Figures tell us that it was called 100,000 times and consumed 405ms on CPU. We also learn that it was called from an unnamed function located at main.lua:0, which is the toplevel lua code of main.lua file, and that all the time (100%) spent in myFunction was due to being called by main.lua.

More interestingly, we discover that 65% of the time (265ms) was spent in calls to function c located at main.lua:27, and that c was called 200,000 times, twice per call.

The next chunk is about function c: 40% of the time of c was spent in math.cos(), and 60% in the function itself.

We know that calling a function is expensive, and that c function is rather simple. Lets try to inline it:

local function myFunction(a)
	return math.cos(a*math.pi/180)+math.cos((a+1)*math.pi/180)
end

Now profiler report looks like this: (truncated)

# Time Ratio Count Function Location
65100%100000<a href="#f2">Unknown</a>@main.lua:0:033FC4FC
<a id="f3">[3]</a> 65 73%100000myFunction@main.lua:26:033FB670
17 27%200000<a href="#f4">cos</a>=[C] 6E416FE0(cos)
 
17100%200000<a href="#f3">myFunction</a>@main.lua:26:033FB670
<a id="f4">[4]</a> 17100%200000cos=[C] 6E416FE0(cos)


myFunction is already faster: 65ms now where we had 405ms before.

We still call math.cos two times. Lets make it (and math.pi) local.

local function myFunction(a)
	local cos=math.cos
	local pi=math.pi
	return cos(a*pi/180)+cos((a+1)*pi/180)
end

Now the profiler report:

# Time Ratio Count Function Location
60100%100000<a href="#f2">Unknown</a>@main.lua:0:033FAC64
<a id="f3">[3]</a> 60 71%100000myFunction@main.lua:26:033FD1E8
17 29%200000<a href="#f4">cos</a>=[C] 6E416FE0(cos)


We saved time in myFunction, while cos() took the same time.

What if we use Gideros deg to rad operator instead of math.pi and 180 constant?

local function myFunction(a)
	local cos=math.cos
	return cos(^<a)+cos(^<(a+1))
end

Profiler report:

# Time Ratio Count Function Location
57100%100000<a href="#f2">Unknown</a>@main.lua:0:033FC4FC
<a id="f3">[3]</a> 57 69%100000myFunction@main.lua:26:033FB9DC
17 31%200000<a href="#f4">cos</a>=[C] 6E416FE0(cos)


We saved a few more precious milliseconds!

Conclusion

As you can see, the profiler is a useful tool to spot CPU bottlenecks in your app.

Sometimes a few minor changes in the code can make a big difference. In general, avoid table access, avoid function calls, avoid duplicate computations.


PREV.: File_system
END