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authorNorbert Thiebaud <nthiebaud@gmail.com>2012-09-16 01:59:07 -0500
committerStephan Bergmann <sbergman@redhat.com>2012-09-17 14:34:36 +0200
commitafbc57927854c423e12206c048bbe7c285a4d9a6 (patch)
tree573922dd4b17a414e4ef0ebba4a53d257a153118
parent581aa2ae225c0d61f65025a5b0155820818e89e0 (diff)
add osl_atomic_* api to allow for inlined atomic increment/decrement
atomic increment/decrement is provided by osl_increment/decrementInterlockedCount() but that is a exported dll function, so it cannot be inlined. valgrind analysis of a run, loading a medium sized spreadsheet, shows that these 2 functions were called 3.5 millions times for a total cost of 55 millions of instructions... a cost of 8 instructions per call, which is at least a 300% overhead since an atomic inc/dec is 2 instructions iow we could save about 1% of the total instruction count of that run(4.6B) We cannot change the existing api, as this would break ABI. but we can add a new api. and migrate internal user to it. osl_atomic_decrement/osl_atomic_increment do the same task, than osl_*IntelockedCount() but do that inlined if possible. Note that this version only optimize the case GCC with atomic built-in. but support for other case should not be very hard. follows-up patches will replace the use of the osl_*InterlockedCount() in the product with their osl_atomic_* equivalent. Change-Id: If4dcbf94ea6f62eb6d55d30613fe65878ffb8023 Signed-off-by: Stephan Bergmann <sbergman@redhat.com>
-rw-r--r--sal/inc/osl/interlck.h38
1 files changed, 38 insertions, 0 deletions
diff --git a/sal/inc/osl/interlck.h b/sal/inc/osl/interlck.h
index 858f99f854d5..f8cd56e6e72b 100644
--- a/sal/inc/osl/interlck.h
+++ b/sal/inc/osl/interlck.h
@@ -52,10 +52,48 @@ SAL_DLLPUBLIC oslInterlockedCount SAL_CALL osl_incrementInterlockedCount(oslInte
*/
SAL_DLLPUBLIC oslInterlockedCount SAL_CALL osl_decrementInterlockedCount(oslInterlockedCount* pCount);
+
+/** Increments the count variable addressed by pCount.
+ @param pCount Address of counter variable
+ @return The result of the operation is zero, the value of the count variable.
+*/
+
+/// @cond INTERNAL
+
+/** Increments the count variable addressed by p.
+ @param p Address of counter variable
+ @attention This functionality should only be used internally within
+ LibreOffice.
+
+ @return The adjusted value of the count variable.
+*/
+#if defined( HAVE_GCC_BUILTIN_ATOMIC )
+# define osl_atomic_increment(p) __sync_add_and_fetch((p), 1)
+#else
+# define osl_atomic_increment(p) osl_incrementInterlockedCount(p)
+#endif
+
+
+/** Decrement the count variable addressed by p.
+ @param p Address of counter variable
+ @attention This functionality should only be used internally within
+ LibreOffice.
+
+ @return The adjusted value of the count variable.
+*/
+#if defined( HAVE_GCC_BUILTIN_ATOMIC )
+# define osl_atomic_decrement(p) __sync_sub_and_fetch((p), 1)
+#else
+# define osl_atomic_decrement(p) osl_decrementInterlockedCount(p)
+#endif
+
+/// @endcond
+
#ifdef __cplusplus
}
#endif
+
#endif /* _OSL_INTERLOCK_H_ */