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authorLukas Larsson <[email protected]>2018-05-21 16:56:41 +0200
committerLukas Larsson <[email protected]>2018-05-21 16:56:41 +0200
commit29871fb6086b535104b10703dd524781e87e0800 (patch)
tree1436b47255d78be4f1b35a8364b5eec024d863d9
parent9cc697fe2cda12ed2d32fb134ed5584f248f9377 (diff)
parentd5dc5584884488c8fcb5710997a14c2c418692f3 (diff)
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Merge branch 'lukas/erts/cpu_time_thread/OTP-15090'
* lukas/erts/cpu_time_thread/OTP-15090: erts: Make cpu_timestamp use per thread on Linux
-rw-r--r--erts/aclocal.m48
-rw-r--r--erts/emulator/beam/erl_bif_trace.c4
-rw-r--r--erts/emulator/beam/erl_time_sup.c2
-rw-r--r--erts/emulator/beam/erl_trace.c14
-rw-r--r--erts/emulator/sys/unix/erl_unix_sys.h10
-rw-r--r--lib/tools/doc/src/fprof.xml10
6 files changed, 21 insertions, 27 deletions
diff --git a/erts/aclocal.m4 b/erts/aclocal.m4
index a4d09810bd..99b96eb5bc 100644
--- a/erts/aclocal.m4
+++ b/erts/aclocal.m4
@@ -2645,7 +2645,7 @@ case $erl_gethrvtime in
dnl Check if clock_gettime (linux) is working
dnl
- AC_MSG_CHECKING([if clock_gettime can be used to get process CPU time])
+ AC_MSG_CHECKING([if clock_gettime can be used to get thread CPU time])
save_libs=$LIBS
LIBS="-lrt"
AC_TRY_RUN([
@@ -2659,11 +2659,11 @@ case $erl_gethrvtime in
int i;
struct timespec tp;
- if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &tp) < 0)
+ if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &tp) < 0)
exit(1);
start = ((long long)tp.tv_sec * 1000000000LL) + (long long)tp.tv_nsec;
for (i = 0; i < 100; i++)
- clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &tp);
+ clock_gettime(CLOCK_THREAD_CPUTIME_ID, &tp);
stop = ((long long)tp.tv_sec * 1000000000LL) + (long long)tp.tv_nsec;
if (start == 0)
exit(4);
@@ -2686,7 +2686,7 @@ case $erl_gethrvtime in
case $erl_clock_gettime_cpu_time in
yes)
AC_DEFINE(HAVE_CLOCK_GETTIME_CPU_TIME,[],
- [define if clock_gettime() works for getting process time])
+ [define if clock_gettime() works for getting thread time])
LIBRT=-lrt
;;
cross)
diff --git a/erts/emulator/beam/erl_bif_trace.c b/erts/emulator/beam/erl_bif_trace.c
index f9d351e69e..9861483bf0 100644
--- a/erts/emulator/beam/erl_bif_trace.c
+++ b/erts/emulator/beam/erl_bif_trace.c
@@ -643,12 +643,12 @@ Eterm erts_internal_trace_3(BIF_ALIST_3)
SysTimespec tp;
int i;
- if (sys_get_proc_cputime(start, tp) < 0)
+ if (sys_get_cputime(start, tp) < 0)
goto error;
start = ((SysCpuTime)tp.tv_sec * 1000000000LL) +
(SysCpuTime)tp.tv_nsec;
for (i = 0; i < 100; i++)
- sys_get_proc_cputime(stop, tp);
+ sys_get_cputime(stop, tp);
stop = ((SysCpuTime)tp.tv_sec * 1000000000LL) +
(SysCpuTime)tp.tv_nsec;
if (start == 0) goto error;
diff --git a/erts/emulator/beam/erl_time_sup.c b/erts/emulator/beam/erl_time_sup.c
index 4f91d9ad07..29c698e34f 100644
--- a/erts/emulator/beam/erl_time_sup.c
+++ b/erts/emulator/beam/erl_time_sup.c
@@ -1860,7 +1860,7 @@ void erts_get_now_cpu(Uint* megasec, Uint* sec, Uint* microsec) {
SysCpuTime t;
SysTimespec tp;
- sys_get_proc_cputime(t, tp);
+ sys_get_cputime(t, tp);
*microsec = (Uint)(tp.tv_nsec / 1000);
t = (tp.tv_sec / 1000000);
*megasec = (Uint)(t % 1000000);
diff --git a/erts/emulator/beam/erl_trace.c b/erts/emulator/beam/erl_trace.c
index f074dd8bdb..f4161b14f2 100644
--- a/erts/emulator/beam/erl_trace.c
+++ b/erts/emulator/beam/erl_trace.c
@@ -625,20 +625,6 @@ erts_get_system_profile(void) {
return profile;
}
-
-#ifdef HAVE_ERTS_NOW_CPU
-# define GET_NOW(m, s, u) \
-do { \
- if (erts_cpu_timestamp) \
- erts_get_now_cpu(m, s, u); \
- else \
- get_now(m, s, u); \
-} while (0)
-#else
-# define GET_NOW(m, s, u) do {get_now(m, s, u);} while (0)
-#endif
-
-
static void
write_sys_msg_to_port(Eterm unused_to,
Port* trace_port,
diff --git a/erts/emulator/sys/unix/erl_unix_sys.h b/erts/emulator/sys/unix/erl_unix_sys.h
index 10adf80875..5bfe5a8e2d 100644
--- a/erts/emulator/sys/unix/erl_unix_sys.h
+++ b/erts/emulator/sys/unix/erl_unix_sys.h
@@ -292,6 +292,8 @@ erts_sys_perf_counter()
/*
* Functions for measuring CPU time
+ *
+ * Note that gethrvtime is time per process and clock_gettime is per thread.
*/
#if (defined(HAVE_GETHRVTIME) || defined(HAVE_CLOCK_GETTIME_CPU_TIME))
@@ -300,15 +302,15 @@ typedef struct timespec SysTimespec;
#if defined(HAVE_GETHRVTIME)
#define sys_gethrvtime() gethrvtime()
-#define sys_get_proc_cputime(t,tp) (t) = sys_gethrvtime(), \
- (tp).tv_sec = (time_t)((t)/1000000000LL), \
- (tp).tv_nsec = (long)((t)%1000000000LL)
+#define sys_get_cputime(t,tp) (t) = sys_gethrvtime(), \
+ (tp).tv_sec = (time_t)((t)/1000000000LL), \
+ (tp).tv_nsec = (long)((t)%1000000000LL)
int sys_start_hrvtime(void);
int sys_stop_hrvtime(void);
#elif defined(HAVE_CLOCK_GETTIME_CPU_TIME)
#define sys_clock_gettime(cid,tp) clock_gettime((cid),&(tp))
-#define sys_get_proc_cputime(t,tp) sys_clock_gettime(CLOCK_PROCESS_CPUTIME_ID,(tp))
+#define sys_get_cputime(t,tp) sys_clock_gettime(CLOCK_THREAD_CPUTIME_ID,(tp))
#endif
#endif
diff --git a/lib/tools/doc/src/fprof.xml b/lib/tools/doc/src/fprof.xml
index 4c9e48045e..72624bd33b 100644
--- a/lib/tools/doc/src/fprof.xml
+++ b/lib/tools/doc/src/fprof.xml
@@ -328,10 +328,16 @@
purposes. This option is only
allowed with the <c>start</c> option.</item>
<tag><c>cpu_time</c>| <c>{cpu_time, bool()}</c></tag>
- <item>The options <c>cpu_time</c> or <c>{cpu_time, true></c>
+ <item>The options <c>cpu_time</c> or <c>{cpu_time, true}</c>
makes the timestamps in the trace be in CPU time instead
of wallclock time which is the default. This option is
- only allowed with the <c>start</c> option.</item>
+ only allowed with the <c>start</c> option.
+ <warning><p>Getting correct values out of cpu_time can be difficult.
+ The best way to get correct values is to run using a single
+ scheduler and bind that scheduler to a specific CPU,
+ i.e. <c>erl +S 1 +sbt db</c>.</p>
+ </warning>
+ </item>
<tag><c>{procs, PidSpec}</c>| <c>{procs, [PidSpec]}</c></tag>
<item>Specifies which processes that shall be traced. If
this option is not given, the calling process is