Firefox OS/Performance/Profiling
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Profiling with the gecko profiler
See these instructions. Patches are in-flight to get native stacks in profiles, but that's not in default configurations yet.
Profiling with perf
The perf utility is a performance analysis tools for Linux.
Setup
The profiling data is collected at target device, and the report been generated at host side.
You need to install perf tool at host side, and create a directory for kernel and libraries with symbols.
- Install perf at host side for Ubuntu
$ sudo apt-get install linux-tools $ perf --version perf version 3.0.17
- Create direcotry for libaries with symbols
Here's a B2G makefile helper to create this directory.
$ make perf-create-symfs
Real time report
On target device, use perf top to generate and display performance counters in real time.
# perf top -p `pidof b2g`
The output will be like this:
PerfTop: 388 irqs/sec kernel:13.1% exact: 0.0% [1000Hz cycles], (target_pid: 7852)
-------------------------------------------------------------------------------
samples pcnt function DSO
_______ _____ __________________________________ _________________
403.00 31.8% _downsample_2x2_rgba8888 libGLESv2_mali.so
119.00 9.4% JaegerStubVeneer libxul.so
93.00 7.3% _raw_spin_unlock_irqrestore [kernel.kallsyms]
59.00 4.7% _m200_texture_deinterleave_16x16_b libMali.so
56.00 4.4% memcpy libc.so
40.00 3.2% finish_task_switch [kernel.kallsyms]
37.00 2.9% vfprintf libc.so
23.00 1.8% _gles_fb_tex_sub_image_2d libGLESv2_mali.so
16.00 1.3% __sfvwrite libc.so
16.00 1.3% __do_softirq [kernel.kallsyms]
15.00 1.2% __memzero [kernel.kallsyms]
13.00 1.0% getnstimeofday [kernel.kallsyms]
12.00 0.9% _gles_generate_mipmaps_sw_16x16blo libGLESv2_mali.so
12.00 0.9% snprintf libc.so
12.00 0.9% __divsi3 libmozglue.so
10.00 0.8% v7_dma_clean_range [kernel.kallsyms]
Recording for a period and generating report
Record at target side: (Hit CTRL-C to stop recording)
# perf record -o /data/local/perf.data -p `pidof b2g`
Generate report at host side:
$ adb pull /data/local/perf.data . $ perf report --symfs=/tmp/b2g_symfs_galaxys2 --vmlinux=/vmlinux
The output will be like this:
# Events: 4K cycles
#
# Overhead Command Shared Object
# ........ ....... ................. ...............................................................................................
#
8.00% b2g perf-7852.map [.] 0x438413fc
4.46% b2g [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
4.36% b2g [unknown] [.] 0x43843500
2.61% b2g [kernel.kallsyms] [k] finish_task_switch
1.69% b2g libxul.so [.] JaegerStubVeneer
1.20% b2g libxul.so [.] TypedArrayTemplate<float>::obj_getElement(JSContext*, JSObject*, JSObject*, unsigned int, J
1.06% b2g libxul.so [.] void js::mjit::stubs::SetElem<0>(js::VMFrame&)
1.05% b2g libxul.so [.] js::mjit::stubs::GetElem(js::VMFrame&)
1.01% b2g libc.so [.] pthread_mutex_lock
1.00% b2g libc.so [.] memcpy
0.90% b2g libxul.so [.] JSObject::nativeLookup(JSContext*, int)
0.88% b2g [kernel.kallsyms] [k] sub_preempt_count
0.86% b2g libGLESv2_mali.so [.] 0xa3a0
0.82% b2g [kernel.kallsyms] [k] add_preempt_count
0.80% b2g [kernel.kallsyms] [k] __do_softirq
0.79% b2g libxul.so [.] js_IsTypedArray(JSObject*)
0.78% b2g libMali.so [.] 0x13be8
0.67% b2g libxul.so [.] js::GetPropertyHelper(JSContext*, JSObject*, int, unsigned int, JS::Value*)
0.66% b2g libxul.so [.] js::PropertyTable::search(int, bool)
0.66% b2g libxul.so [.] js_GetProperty(JSContext*, JSObject*, JSObject*, int, JS::Value*)
0.65% b2g libc.so [.] pthread_mutex_unlock
0.59% b2g libxul.so [.] castNativeFromWrapper(JSContext*, JSObject*, unsigned int, nsISupports**, JS::Value*, XPCLa
0.57% b2g libmozglue.so [.] __udivsi3
0.53% b2g libxul.so [.] mozilla::gl::GLContextEGL::MakeCurrentImpl(bool)
0.52% b2g libxul.so [.] XPCWrappedNative::CallMethod(XPCCallContext&, XPCWrappedNative::CallMode)
0.49% b2g libxul.so [.] js::TypedArray::getTypedArray(JSObject*)
0.49% b2g libxul.so [.] js::GetPropertyOperation(JSContext*, unsigned char*, JS::Value const&, JS::Value*)
0.48% b2g [kernel.kallsyms] [k] vector_swi
0.47% b2g [kernel.kallsyms] [k] get_parent_ip
0.42% b2g libxul.so [.] DisabledGetElem(js::VMFrame&, js::mjit::ic::GetElementIC*)
Recording with callgraph
Use option '-g' to do callgraph recording:
# perf record -g -o /data/local/perf.data -p `pidof b2g`
Note:
- To get correct call graph report, you need to compile libaries with "-fno-omit-frame-pointer".
- On SGS2 device, it's easy to crash when doing perf with callgraph, this is an issue to be fixed.
System-wide and specific application profiling
Use option '-a' to do system-wide profiling:
# perf record -o /data/local/perf.data -a
Profiling on specified command:
# perf -o /data/local/perf.data /system/b2g/b2g
Use option '-p' to profile an existing process: (On some devices there's no pidof, and you need to use ps to find out b2g PID)
# perf record -o /data/local/perf.data -p `pidof b2g`
Makefile helpers for perf
Here are B2G makefile helpers to generate perf reports at host side.
- Create direcotry for libaries with symbols
$ make perf-create-symfs
- Remove directory for libaries with symbols
$ make perf-clean-symfs
- Real time perf report for system wide
$ make perf-top
- Real time report for B2G process
$ make perf-top-b2g
- Summary perf report for system wide
$ make perf-report
- Summary perf report for B2G process
$ make perf-report-b2g
- Change recording duration
For perf-report-*, it automatically records for 10 seconds then generate report. You can change it by giving argument "RECORD_DURATION".
Below is an example to record for 30 seconds:
$ make perf-report RECORD_DURATION=30