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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>
This commit is contained in:
Bob Moore 2008-11-12 15:02:00 +08:00 committed by Len Brown
parent 84d4db7c52
commit 96411a6304
1 changed files with 25 additions and 4 deletions
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29
drivers/acpi/dispatcher/dsopcode.c
View File

@ -1140,9 +1140,28 @@ 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
@ -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;