Add multi-architecture support in telemetry.

tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py

Index: tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
diff --git a/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py b/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
index 2a8fd9fce10ff71ce973f03882b378d8afb1db27..70b6cc61814b083a27119f290d6c798426769eb8 100644
--- a/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
+++ b/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
@@ -225,10 +225,11 @@ def PrepareDeviceForPerf(device):
   Returns:
     The path to the installed perf binary on the device.
   """
-  android_prebuilt_profiler_helper.InstallOnDevice(device, 'perf')
+  perf_binary = 'perf_' + device.GetProp('ro.product.cpu.abi')

[tonyg, 2014/10/10 16:51:14]

This is a general problem, not specific to the perf binary or to the android
platform.

Take a look at support_binaries.py and how it chooses the folder automatically
based on the platform. I had pictured that we'd add another level of nesting for
the architecture -- here:

def _GetBinPath(binary_name, platform_name):
  # TODO(tonyg): Add another nesting level for architecture_name.
  return os.path.join(path.GetTelemetryDir(), 'bin', platform_name, binary_name)

So then instead of renaming perf.sha1, we'd move it to
bin/android/armeabi-v7a/perf.sha1.

Would you be willing to rework this CL to generalize this?

[pasko, 2014/10/10 17:04:07]

Oops, I also recently added perfhost_precise and perfhost_trusty :)

I am slightly biased towards perf_armeabi-v7a because in the future we might
need to support multiple ABIs on the single device, which probably means
multiple perf binaries installed side by side (not 100% sure about that). We
would probably never need to run two different perf binaries concurrently
anyway, but maybe it would be easier to tell which binary is used on the device
by looking at the filename itself or the logs on the bots.

Other applications do similar things. For example, the GCC binary I use is named
as "arm-linux-androideabi-gcc".

But I am not strongly opposed to the alternative you proposed, it would work
either way.

+  android_prebuilt_profiler_helper.InstallOnDevice(device, perf_binary)
   # Make sure kernel pointers are not hidden.
   device.WriteFile('/proc/sys/kernel/kptr_restrict', '0', as_root=True)
-  return android_prebuilt_profiler_helper.GetDevicePath('perf')
+  return android_prebuilt_profiler_helper.GetDevicePath(perf_binary)
 
 
 def GetToolchainBinaryPath(library_file, binary_name):