@@ -83,5 +83,6 @@ ld {
__libos_release; __libos_version; __libos_abi;
# stub symbols for libos support
__libos_map_library;
+ __hp_timing_disabled;
}
}
@@ -46,6 +46,8 @@
#include <assert.h>
+#include "libos.h"
+
/* Only enables rtld profiling for architectures which provides non generic
hp-timing support. The generic support requires either syscall
(clock_gettime), which will incur in extra overhead on loading time.
@@ -58,9 +60,18 @@
# define RTLD_TIMING_SET(var, value) (var) = (value)
# define RTLD_TIMING_REF(var) &(var)
+bool __hp_timing_disabled __attribute__((weak))= false;
+# define HP_TIMING_DISABLED __hp_timing_disabled
+LIBOS_NOTES("variables", LIBOS_NOTE_VARIABLE,
+ __hp_timing_disabled, 1, "__hp_timing_disabled");
+
static inline void
rtld_timer_start (hp_timing_t *var)
{
+ if (HP_TIMING_DISABLED) {
+ memset(var, 0, sizeof(*var));
+ return;
+ }
HP_TIMING_NOW (*var);
}
@@ -68,6 +79,8 @@ static inline void
rtld_timer_stop (hp_timing_t *var, hp_timing_t start)
{
hp_timing_t stop;
+ if (HP_TIMING_DISABLED)
+ return;
HP_TIMING_NOW (stop);
HP_TIMING_DIFF (*var, start, stop);
}
@@ -76,6 +89,8 @@ static inline void
rtld_timer_accum (hp_timing_t *sum, hp_timing_t start)
{
hp_timing_t stop;
+ if (HP_TIMING_DISABLED)
+ return;
rtld_timer_stop (&stop, start);
HP_TIMING_ACCUM_NT(*sum, stop);
}
@@ -87,6 +102,7 @@ rtld_timer_accum (hp_timing_t *sum, hp_timing_t start)
# define rtld_timer_start(var)
# define rtld_timer_stop(var, start)
# define rtld_timer_accum(sum, start)
+# define HP_TIMING_DISABLED false
#endif
/* Avoid PLT use for our local calls at startup. */
@@ -2748,6 +2764,8 @@ static void
print_statistics_item (const char *title, hp_timing_t time,
hp_timing_t total)
{
+ if (HP_TIMING_DISABLED)
+ return;
char cycles[HP_TIMING_PRINT_SIZE];
HP_TIMING_PRINT (cycles, sizeof (cycles), time);
@@ -2779,7 +2797,7 @@ __attribute ((noinline))
print_statistics (const hp_timing_t *rtld_total_timep)
{
#if HP_TIMING_INLINE
- {
+ if (!HP_TIMING_DISABLED) {
char cycles[HP_TIMING_PRINT_SIZE];
HP_TIMING_PRINT (cycles, sizeof (cycles), *rtld_total_timep);
_dl_debug_printf ("\nruntime linker statistics:\n"
This patch introduce runtime option, __hp_timing_disabled with weak symbol to disable rtld profiling with HP_TIMING_INLINE. Because some LibOS doesn't suport rdtsc/rdtscp (e.g. SGX enclave), this allows LibOS to disable HP_TIMING profiling on startup. The impact on traditional runtime is "if (__hp_timing_disabled)". Signed-off-by: Isaku Yamahata <isaku.yamahata@gmail.com> --- elf/Versions | 1 + elf/rtld.c | 20 +++++++++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-)