Added rudimentary profiling

Simple cycle-measuring based profiling setup in tests/prof.c
- uses rdtsc instruction for cycle-level measurement
- averages each test repeatedly over PROF_INTERVAL cycles
- test best result of PROF_RUNS runs to throw out unexpected interrupts
- percentage comparison with previous versions for tangible results

To profile a single instance:
make prof

To compare two runs (this will show rough measurement error):
make prof > results.txt && cat results.txt | make prof

.travis.yml

@@ -1,3 +1,15 @@
 script:
+      # Strict compilation of library
     - CFLAGS='-pedantic -Werror' make
+
+      # Runtime tests
     - make test
+
+      # Relative profiling with current master
+    - if ( git clone https://github.com/geky/events tests/master &&
+           make -s -C tests/master prof | tee tests/results.txt ) ;
+      then
+        cat tests/results.txt | make prof ; 
+      else
+        make prof ;
+      fi

Makefile

@@ -9,11 +9,6 @@ OBJ := $(SRC:.c=.o)
 DEP := $(SRC:.c=.d)
 ASM := $(SRC:.c=.s)
 
-TESTS = tests/tests
-TSRC += $(wildcard tests/*.c)
-TOBJ := $(TSRC:.c=.o)
-TDEP := $(TSRC:.c=.d)
-
 ifdef DEBUG
 CFLAGS += -O0 -g3 -DMU_DEBUG
 CFLAGS += -fkeep-inline-functions
@@ -33,9 +28,13 @@ LFLAGS += -lpthread
 
 all: $(TARGET)
 
-test: $(TOBJ) $(OBJ)
-	$(CC) $(CFLAGS) $^ $(LFLAGS) -o $(TESTS)
-	$(TESTS)
+test: tests/tests.o $(OBJ)
+	$(CC) $(CFLAGS) $^ $(LFLAGS) -o tests/tests
+	tests/tests
+
+prof: tests/prof.o $(OBJ)
+	$(CC) $(CFLAGS) $^ $(LFLAGS) -o tests/prof
+	tests/prof
 
 asm: $(ASM)
 
@@ -55,8 +54,8 @@ size: $(OBJ)
 
 clean:
 	rm -f $(TARGET)
-	rm -f $(TESTS)
-	rm -f $(TOBJ) $(TDEP)
+	rm -f tests/tests tests/tests.o tests/tests.d
+	rm -f tests/prof tests/prof.o tests/prof.d
 	rm -f $(OBJ)
 	rm -f $(DEP)
 	rm -f $(ASM)