Merge "docs: remove out-of-date performance info" into nyc-dev

This commit is contained in:
Mark Lu
2016-07-11 20:12:32 +00:00
committed by Android (Google) Code Review

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@@ -43,7 +43,7 @@ processors running at different speeds. It's not even generally the case
that you can simply say "device X is a factor F faster/slower than device Y",
and scale your results from one device to others. In particular, measurement
on the emulator tells you very little about performance on any device. There
are also huge differences between devices with and without a
are also huge differences between devices with and without a
<acronym title="Just In Time compiler">JIT</acronym>: the best
code for a device with a JIT is not always the best code for a device
without.</p>
@@ -88,7 +88,7 @@ parallel single one-dimension arrays:</p>
but this also generalizes to the fact that two parallel arrays of ints
are also a <strong>lot</strong> more efficient than an array of {@code (int,int)}
objects. The same goes for any combination of primitive types.</li>
<li>If you need to implement a container that stores tuples of {@code (Foo,Bar)}
objects, try to remember that two parallel {@code Foo[]} and {@code Bar[]} arrays are
generally much better than a single array of custom {@code (Foo,Bar)} objects.
@@ -401,19 +401,6 @@ final fields too.)
need to solve. Make sure you can accurately measure your existing performance,
or you won't be able to measure the benefit of the alternatives you try.</p>
<p>Every claim made in this document is backed up by a benchmark. The source
to these benchmarks can be found in the <a
href="http://code.google.com/p/dalvik/source/browse/#svn/trunk/benchmarks">code.google.com
"dalvik" project</a>.</p>
<p>The benchmarks are built with the
<a href="http://code.google.com/p/caliper/">Caliper</a> microbenchmarking
framework for Java. Microbenchmarks are hard to get right, so Caliper goes out
of its way to do the hard work for you, and even detect some cases where you're
not measuring what you think you're measuring (because, say, the VM has
managed to optimize all your code away). We highly recommend you use Caliper
to run your own microbenchmarks.</p>
<p>You may also find
<a href="{@docRoot}tools/debugging/debugging-tracing.html">Traceview</a> useful
for profiling, but it's important to realize that it currently disables the JIT,