add ts test

CMakeLists.txt

@@ -19,7 +19,7 @@ target_compile_options(topo PRIVATE ${C_FLAGS} ${XML_CFLAGS})
 target_include_directories(topo PRIVATE ${XML_INCLUDE_DIRS})
 target_link_libraries(topo PRIVATE ${XML_LINK_LIBRARIES})
 
-add_executable(test test/topo.c)
+add_executable(test test/test.c)
 set_target_properties(test PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/test)
 target_link_libraries(test PRIVATE topo)
 target_compile_options(test PRIVATE ${C_FLAGS})

test/test.c

@@ -0,0 +1,101 @@
+#include <unistd.h>
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "topo.h"
+
+#define S2NS (1000000000UL)
+
+static inline uint64_t
+get_uptime()
+{
+	struct timespec tp;
+	clock_gettime(CLOCK_MONOTONIC, &tp);
+    return (tp.tv_sec * S2NS + tp.tv_nsec);
+}
+
+void test(const char * case_name, struct timespec * ts)
+{
+    uint64_t slow;
+    uint64_t fast;
+
+    slow = get_uptime();
+    if (nanosleep(ts, NULL) != 0) {
+        perror("nanosleep() interrupted!");
+        exit(-1);
+    }
+    slow = get_uptime() - slow;
+
+    fast = topo_uptime_ns();
+    if (nanosleep(ts, NULL) != 0) {
+        perror("nanosleep() interrupted!");
+        exit(-1);
+    }
+    fast = topo_uptime_ns() - fast;
+
+    printf("%s: clock_gettime(): %lu, topo_uptime_ns(): %lu, %% diff: %.2f%%\n", case_name, slow, fast, ((float)fast - (float)slow) / (float)slow * 100);
+}
+
+int ts_test()
+{
+    struct timespec ts;
+    // 1s
+    ts.tv_nsec = 0;
+    ts.tv_sec = 1;
+    test("1s", &ts);
+
+    // 100ms
+    ts.tv_nsec = 100000000;
+    ts.tv_sec = 0;
+    test("100ms", &ts);
+
+    // 10ms
+    ts.tv_nsec = 10000000;
+    ts.tv_sec = 0;
+    test("10ms", &ts);
+
+    // 1ms
+    ts.tv_nsec = 1000000;
+    ts.tv_sec = 0;
+    test("1ms", &ts);
+
+    // 100us
+    ts.tv_nsec = 100000;
+    ts.tv_sec = 0;
+    test("100us", &ts);
+
+    // 10us
+    ts.tv_nsec = 10000;
+    ts.tv_sec = 0;
+    test("10us", &ts);
+
+    // 1us
+    ts.tv_nsec = 1000;
+    ts.tv_sec = 0;
+    test("1us", &ts);
+
+    // 100ns
+    ts.tv_nsec = 100;
+    ts.tv_sec = 0;
+    test("100ns", &ts);
+
+    // 10ns
+    ts.tv_nsec = 10;
+    ts.tv_sec = 0;
+    test("10ns", &ts);
+
+    // 1ns
+    ts.tv_nsec = 1;
+    ts.tv_sec = 0;
+    test("1ns", &ts);
+
+    return 0;
+}
+
+int main()
+{
+    topo_init(1, 1);
+    ts_test();
+    return 0;
+}

test/topo.c

@@ -1,8 +0,0 @@
-#include <unistd.h>
-#include "topo.h"
-
-int main()
-{
-    topo_init(1, 1);
-    return 0;
-}

timestamp.c

@@ -1,6 +1,9 @@
 #include <stdint.h>
 #include <immintrin.h>
 #include <x86intrin.h>
+#include <errno.h>
+#include <sys/sysctl.h>
+
 #include "topo.h"
 
 static uint64_t sysctl_tsc_freq = 0;
@@ -14,6 +17,23 @@ tsc2ns(uint64_t tsc)
 	    (double)tsc / (double)sysctl_tsc_freq * S2NS);
 }
 
+int
+topo_ts_init(int verbose)
+{
+    int rc;
+    size_t sz = sizeof(sysctl_tsc_freq);
+
+	// init nm_tsc2ns
+	if ((rc = sysctlbyname(
+		 "machdep.tsc_freq", &sysctl_tsc_freq, &sz, NULL, 0)) < 0) {
+		if (verbose) {
+			fprintf(stderr,
+			    "libnm: failed to query tsc frequency via sysctl (%d)\n", errno);
+		}
+	}
+
+    return rc;
+}
 
 uint64_t
 topo_uptime_ns()

topo.c

@@ -386,6 +386,8 @@ _topo_init(int verbose, int alloc_init, struct topo_obj ** obj)
         }
     }
 
+    rc = topo_ts_init(verbose);
+
     if (alloc_init && rc == 0) {
         rc = topo_alloc_init(verbose, *obj);
     }