Merge pull request #133 from plasma-umass/housekeeping

Fix some minor code and style issues

Author: ccurtsinger

Makefile

@@ -15,5 +15,5 @@ install:: all
 	@mkdir -p $(DESTDIR)$(man1dir)
 	@$(RST2MAN) docs/coz.rst $(DESTDIR)$(man1dir)/coz.1
 
-bench::
-	@$(MAKE) -C benchmarks bench
+bench bench_small bench_large::
+	@$(MAKE) -C benchmarks $@

common.mk

@@ -30,7 +30,7 @@ SRCS ?= $(wildcard *.cpp) $(wildcard *.c)
 OBJS ?= $(addprefix obj/,$(patsubst %.cpp,%.o,$(patsubst %.c,%.o,$(SRCS))))
 
 # Prevent errors if files named all, clean, distclean, bench, or test exist
-.PHONY: all clean distclean bench test
+.PHONY: all clean distclean bench bench_small bench_large test
 
 # Targets to build recirsively into $(DIRS)
 RECURSIVE_TARGETS  ?= all clean bench bench_large bench_small test install check

libcoz/inspect.cpp

@@ -246,7 +246,7 @@ unordered_map<string, uintptr_t> get_loaded_files() {
 
     // If this is an executable mapping of an absolute path, include it
     if(perms[2] == 'x' && path[0] == '/') {
-      result[path] = base;
+      result[path] = base - offset;
     }
   }
 

libcoz/perf.cpp

@@ -76,7 +76,9 @@ perf_event::perf_event(struct perf_event_attr& pe, pid_t pid, int cpu) :
   // If sampling, map the perf event file
   if(pe.sample_type != 0 && pe.sample_period != 0) {
     void* ring_buffer = mmap(NULL, MmapSize, PROT_READ | PROT_WRITE, MAP_SHARED, _fd, 0);
-    REQUIRE(ring_buffer != MAP_FAILED) << "Failed to mmap perf event file";
+    REQUIRE(ring_buffer != MAP_FAILED) << "Mapping perf_event ring buffer failed. "
+        << "Make sure the current user has permission to invoke the perf tool, and that "
+        << "the program being profiled does not use an excessive number of threads (>1000).\n";
 
     _mapping = reinterpret_cast<struct perf_event_mmap_page*>(ring_buffer);
   }

libcoz/profiler.cpp

@@ -466,6 +466,8 @@ void* profiler::start_profiler_thread(void* arg) {
   spinlock* l = (spinlock*)arg;
   profiler::get_instance().profiler_thread(*l);
   real::pthread_exit(nullptr);
+  // Unreachable return silences compiler warning
+  return nullptr;
 }
 
 void profiler::samples_ready(int signum, siginfo_t* info, void* p) {