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authorBob Moore <robert.moore@intel.com>2008-11-12 15:02:00 +0800
committerLen Brown <len.brown@intel.com>2008-12-29 22:38:36 -0500
commit96411a630412f057d365aa1e9de7d23c069d627a (patch)
tree4ed41f48fefb600ace6be82b9c6963e2e90b2a10 /drivers
parent84d4db7c528e23f8c9ae0be12960549347003eeb (diff)
ACPICA: Optimize execution of AML While loops
Previously, a control state object was allocated and freed for each execution of the loop. The optimization is to simply reuse the control state for each iteration. This speeds up the raw loop execution time by about 5%. Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/acpi/dispatcher/dsopcode.c29
1 files changed, 25 insertions, 4 deletions
diff --git a/drivers/acpi/dispatcher/dsopcode.c b/drivers/acpi/dispatcher/dsopcode.c
index 69fae5905bb..5cd406676c2 100644
--- a/drivers/acpi/dispatcher/dsopcode.c
+++ b/drivers/acpi/dispatcher/dsopcode.c
@@ -1140,10 +1140,29 @@ acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state,
op->common.aml_opcode, walk_state));
switch (op->common.aml_opcode) {
- case AML_IF_OP:
case AML_WHILE_OP:
/*
+ * If this is an additional iteration of a while loop, continue.
+ * There is no need to allocate a new control state.
+ */
+ if (walk_state->control_state) {
+ if (walk_state->control_state->control.aml_predicate_start
+ == (walk_state->parser_state.aml - 1)) {
+
+ /* Reset the state to start-of-loop */
+
+ walk_state->control_state->common.state =
+ ACPI_CONTROL_CONDITIONAL_EXECUTING;
+ break;
+ }
+ }
+
+ /*lint -fallthrough */
+
+ case AML_IF_OP:
+
+ /*
* IF/WHILE: Create a new control state to manage these
* constructs. We need to manage these as a stack, in order
* to handle nesting.
@@ -1248,8 +1267,13 @@ acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state,
/* Predicate was true, go back and evaluate it again! */
status = AE_CTRL_PENDING;
+ walk_state->aml_last_while =
+ walk_state->control_state->control.aml_predicate_start;
+ break;
}
+ /* Predicate was false, terminate this while loop */
+
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
"[WHILE_OP] termination! Op=%p\n", op));
@@ -1257,9 +1281,6 @@ acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state,
control_state =
acpi_ut_pop_generic_state(&walk_state->control_state);
-
- walk_state->aml_last_while =
- control_state->control.aml_predicate_start;
acpi_ut_delete_generic_state(control_state);
break;