Speed up map creation.
- Rewrite the Maps::Parse to use open, and a buffer on the stack.
- Rewrite the line parser away from sscanf. The current way sscanf
is used does not catch many malformed lines. In addition, this
new version improves performance by 50% over sscanf on sailfish.
- Add a lot of unit tests for the parser to make sure there are
no problems. In addition, add a special line that was not rejected
with the previous version of the code.
- Add new accessor to get the map at a particular index.
- Add a backtrace benchmark for map creation for both new and old.
This cl results in ~5% speedup and makes the new unwinder map creation
about the same for 64 bit. It's still a bit slower, but not by much.
On 32 bit, we are still about 5% slower than the old creation method,
though.
Bug: 23762183
Test: libunwindstack unit tests pass. Ran the new benchmarks.
Change-Id: Id4431e539f400984e6fad62153fdf4152d518322
diff --git a/libbacktrace/Android.bp b/libbacktrace/Android.bp
index c58d777..12c72b4 100644
--- a/libbacktrace/Android.bp
+++ b/libbacktrace/Android.bp
@@ -240,3 +240,17 @@
},
},
}
+
+cc_benchmark {
+ name: "backtrace_benchmarks",
+ defaults: ["libbacktrace_common"],
+
+ srcs: [
+ "backtrace_benchmarks.cpp",
+ ],
+
+ shared_libs: [
+ "libbacktrace",
+ "libbase",
+ ],
+}