Begin porting string performance tests to benchtests

This is the initial support for string function performance tests,
along with copying tests for memcpy and memcpy-ifunc as proof of
concept.  The string function benchmarks perform operations at
different alignments and for different sizes and compare performance
between plain operations and the optimized string operations.  Due to
this their output is incompatible with the function benchmarks where
we're interested in fastest time, throughput, etc.

In future, the correctness checks in the benchmark tests can be
removed.  Same goes for the performance measurements in the
string/test-*.

1 files changed, 15 insertions, 0 deletions

diff --git a/benchtests/README b/benchtests/README
index 8135069fea..045b7a673d 100644
--- a/benchtests/README
+++ b/benchtests/README
@@ -72,3 +72,18 @@ the same file by using the `name' directive that looks something like this:
 
 See the pow-inputs file for an example of what such a partitioned input file
 would look like.
+
+Benchmark Sets:
+==============
+
+In addition to standard benchmarking of functions, one may also generate
+custom outputs for a set of functions.  This is currently used by string
+function benchmarks where the aim is to compare performance between
+implementations at various alignments and for various sizes.
+
+To add a benchset for `foo':
+
+- Add `foo' to the benchset variable.
+- Write your bench-foo.c that prints out the measurements to stdout.
+- On execution, a bench-foo.out is created in $(objpfx) with the contents of
+  stdout.