Firefox OS/Performance/Profiling - Revision history

Lakrits: Lakrits moved page FirefoxOS/Performance/Profiling to Firefox OS/Performance/Profiling: The official spelling of "Firefox OS" leaves a space between the two parts of the name. It's easier to find a page if the spelling of its name is consistent...

2015-02-01T13:59:58Z

Lakrits moved page FirefoxOS/Performance/Profiling to Firefox OS/Performance/Profiling: The official spelling of "Firefox OS" leaves a space between the two parts of the name. It's easier to find a page if the spelling of its name is consistent...

← Older revision	Revision as of 13:59, 1 February 2015
(No difference)

JerryShih: /* Profiling with systrace */

2014-06-09T11:44:42Z

Profiling with systrace

← Older revision		Revision as of 11:44, 9 June 2014
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	= Profiling with systrace =		= Profiling with systrace =

	Good at: Shows process preemption, shows all calls to instrumented functions, Familiar for android developers		Good at: Shows process preemption, shows all calls to instrumented functions, Familiar for android developers

	Bad at: Requires configure option, higher overhead		Bad at: Requires configure option, higher overhead

	~~'''Better instructions coming~~:~~''' Build with '--enable-systrace' and follow~~ [http://developer.android.com/tools/~~help~~/~~systrace~~.~~html these instructions~~ for ~~systrace~~.~~py]~~.		*Download android sdk to get systrace tool:
			**[http://developer.android.com/sdk/index.html 1. download link]
			**2. the systrace.py tool is at path-to-android-sdk/tools/systrace

			*Enable systrace in B2G:
			**Build with '--enable-systrace' config or just uncomment the MOZ_USE_SYSTRACE define in gecko/tools/profiler/GeckoProfilerImpl.h like:
			<pre>
			#define MOZ_USE_SYSTRACE
			#ifdef MOZ_USE_SYSTRACE
			# define ATRACE_TAG ATRACE_TAG_ALWAYS
			// We need HAVE_ANDROID_OS to be defined for Trace.h.
			// If its not set we will set it temporary and remove it.
			# ifndef HAVE_ANDROID_OS
			# define HAVE_ANDROID_OS
			# define REMOVE_HAVE_ANDROID_OS
			# endif
			</pre>

	~~Note~~: ~~Gecko code is tagged as ATRACE_TAG_ALWAYS, so the command is for your reference~~.		*How to use systrace:
			**[http://developer.android.com/tools/help/systrace.html systrace.py document]
			**./systrace.py --time=10 -o mynewtrace.html sched

	.~~/systrace.py --time=10 -o mynewtrace.html sched~~		Note: Gecko code is tagged as ATRACE_TAG_ALWAYS, so we don't set the category type.

Ctai: /* Profiling with systrace */

2014-06-03T03:47:12Z

Profiling with systrace

← Older revision		Revision as of 03:47, 3 June 2014
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	'''Better instructions coming:''' Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].		'''Better instructions coming:''' Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].

	Note: ~~If you're profiling on device with Android 4.3 and sometimes you can only see B2G process in your profile data, please reboot your device and try to profile again. By the way, gecko~~ code is tagged as ~~'gfx'~~, so the command is for your reference.		Note: Gecko code is tagged as ATRACE_TAG_ALWAYS, so the command is for your reference.

	./systrace.py --time=10 -o mynewtrace.html sched ~~gfx~~		./systrace.py --time=10 -o mynewtrace.html sched

AlisonW: AlisonW moved page B2G/Performance/Profiling to FirefoxOS/Performance/Profiling: per Bug 994464

2014-04-17T00:06:00Z

AlisonW moved page B2G/Performance/Profiling to FirefoxOS/Performance/Profiling: per Bug 994464

← Older revision	Revision as of 00:06, 17 April 2014
(No difference)

Mlee: Mlee moved page B2G/Profiling to B2G/Performance/Profiling: Organizing FxOS Performance Wiki.

2014-04-14T19:18:08Z

Mlee moved page B2G/Profiling to B2G/Performance/Profiling: Organizing FxOS Performance Wiki.

← Older revision	Revision as of 19:18, 14 April 2014
(No difference)

Vincentlin78: /* Profiling with systrace */

2014-03-25T06:25:20Z

Profiling with systrace

← Older revision		Revision as of 06:25, 25 March 2014
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	'''Better instructions coming:''' Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].		'''Better instructions coming:''' Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].

			Note: If you're profiling on device with Android 4.3 and sometimes you can only see B2G process in your profile data, please reboot your device and try to profile again. By the way, gecko code is tagged as 'gfx', so the command is for your reference.

			./systrace.py --time=10 -o mynewtrace.html sched gfx

Bgirard: /* Profiling with systrace */

2014-01-10T04:46:38Z

Profiling with systrace

← Older revision		Revision as of 04:46, 10 January 2014
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	Bad at: Requires configure option, higher overhead		Bad at: Requires configure option, higher overhead

	Better instructions coming.		'''Better instructions coming:''' Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].

	Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].

Bgirard: /* Profiling with systrace */

2014-01-10T04:46:10Z

Profiling with systrace

← Older revision		Revision as of 04:46, 10 January 2014
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	Good at: Shows process preemption, shows all calls to instrumented functions, Familiar for android developers		Good at: Shows process preemption, shows all calls to instrumented functions, Familiar for android developers

	Bad at: Requires configure option, higher overhead		Bad at: Requires configure option, higher overhead

Bgirard: /* Profiling with the gecko profiler */

2014-01-10T04:45:50Z

Profiling with the gecko profiler

← Older revision		Revision as of 04:45, 10 January 2014
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	= Profiling with the gecko profiler =		= Profiling with the gecko profiler =

			Good at: Native stacks (with runtime options) + javascript profiling, low overhead sampling, familiar for gecko developers

	See [https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler#Profiling_Boot_to_Gecko_%28with_a_real_device%29 these instructions]. Patches are in-flight to get native stacks in profiles, but that's not in default configurations yet.		See [https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler#Profiling_Boot_to_Gecko_%28with_a_real_device%29 these instructions]. Patches are in-flight to get native stacks in profiles, but that's not in default configurations yet.

			= Profiling with systrace =

			Good at: Shows process preemption, shows all calls to instrumented functions, Familiar for android developers
			Bad at: Requires configure option, higher overhead

			Better instructions coming.

			Build with '--enable-systrace' and follow [http://developer.android.com/tools/help/systrace.html these instructions for systrace.py].

Mchang: /* Profiling with perf(1) */

2013-10-17T00:39:24Z

Profiling with perf(1)

← Older revision		Revision as of 00:39, 17 October 2013
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	See [https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler#Profiling_Boot_to_Gecko_%28with_a_real_device%29 these instructions]. Patches are in-flight to get native stacks in profiles, but that's not in default configurations yet.		See [https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler#Profiling_Boot_to_Gecko_%28with_a_real_device%29 these instructions]. Patches are in-flight to get native stacks in profiles, but that's not in default configurations yet.

	~~= Profiling with perf(1) =~~

	Work is in progress to make the Linux kernel profiler, called "perf", useful for debugging on B2G. See [https://bugzilla.mozilla.org/show_bug.cgi?id=831611 bug 831611] for more information; the main issue for getting it landed is obtaining stack traces, which [https://bugzilla.mozilla.org/show_bug.cgi?id=856899 bug 856899] goes into more detail on.

	~~== Quick Start ==~~

	This should now work on both Linux and Mac build hosts. Refer to [https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler#Profiling_Boot_to_Gecko_%28with_a_real_device%29 Profiling with the Built in Profiler]. There no longer is need to use a separate branch for the profiler to work.

	~~Essential workflow:~~

	~~# Add 'export MOZ_PROFILING=1' to your B2G .userconfig. Build B2G.~~
	~~# Run profile.sh start~~
	~~# Capture the profile~~
	~~# Upload the profile to [http://people.mozilla.com/~bgirard/cleopatra/ Cleopatra]~~
	~~# Make it faster!~~

	~~== Fine-Tuning ==~~

	By default, perf samples based on the CPU's cycle counter, adjusting the period to gather approximately 4000 samples/sec. However, it gathers nothing while the CPU is idle, and currently Cleopatra (the Gecko profiler front-end) ignores these times — it doesn't display them in the timeline, and its "real interval" is an average over both real inter-sample intervals and idle times.

	Other timers are available; use the -e flag (when running "./run-perf record-sps") to select one. In particular, "-e cpu-clock" uses a real-time interval timer, which gather samples even when the CPU is idle. However, at least on unagi it seems to be restricted to 2500 samples/sec.

	Note that on the miniperf branch, cpu-clock is the default; use "-e cycles" to use the cycle counter. Or try something else; run "perf list" on a Linux host, or look at the table at the top of gonk-misc/miniperf/miniperf-record.c on the miniperf branch. The hardware might not support some of them.

	To set the sample rate, use the -F flag to specify a target frequency (samples/sec) or -c to give an absolute number of cycles (note that the kernel will adjust the CPU speed in response to demand). The "cycle time" for cpu-clock appears to be in nanoseconds regardless of the physical timer used. Note that, at very high rates (empirically, >10 kHz), the CPU may spend enough time gathering samples to noticeably slow down the application being profiled.

	~~== In More Detail ==~~

	The original run-perf.sh commands were "record" and "report", corresponding to those perf(1) commands, except that "record" is run on the device (and the perf.data file pulled afterwards, along with kallsyms) and "report" constructs a symlink farm to provide symbol information. This may be useful to those who are already familiar with perf, but it's not the most obvious interface for new users.

	However: "report" works only on Linux hosts (and not even all of those out of the box, without rebuilding the perf executable, due to library issues), and while "record" will work without "report" it's not very useful — the perf.data format is undocumented, and the code for reading and writing it is not trivial to extract from its Linux dependencies.

	As an alternative to this, "./run-perf.sh minirecord" accepts a subset of the perf record options (-e -c -F -m -o, and defaults to -a -g -e cpu-clock) and obtains output in a simpler format. The actual command it runs, "miniperf-record", is built in gonk-misc with the normal Android makefiles.

	The next layer is "./run-perf.sh sps", which converts the raw profile data to the format used by the Gecko profiler (with symbols). If it was collected with "./run-perf.sh record" then it needs to run perf report, in which case see above about nonportability; for miniperf it reads the file with Python code that should run everywhere.

	~~Finally, "./run-perf.sh record-sps" is just "minirecord" followed by "sps".~~