Sitsofe Wheeler wrote:
Hi Alexey,
Alexey Starikovskiy wrote:
I think the least troubling place to add cond_resched() is then
ACPICA is exiting interpreter.
Please check if the attached patch helps with latencies.
There was no real change (latency was still bad). If you look at the
trace (before your patch) on
http://sucs.org/~sits/test/eeepc-debug/20080923/latency_trace.gz
(700kbyte compressed, 15Mbytes uncompressed) you can see that
acpi_ex_exit_interpreter is only called once near the end of the trace:
cat-5901 0.N.. 270496us : acpi_ex_exit_interpreter
(acpi_ev_address_space_dispatch)
By then the time had already been racked up...
Ok, let's add it to the end of acpi_ps_complete_op() then... They appear
every 100usec or so...
diff --git a/drivers/acpi/parser/psloop.c b/drivers/acpi/parser/psloop.c
index c06238e..33cd061 100644
--- a/drivers/acpi/parser/psloop.c
+++ b/drivers/acpi/parser/psloop.c
@@ -564,6 +564,8 @@ acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
*
******************************************************************************/
+#include <linux/sched.h>
+
static acpi_status
acpi_ps_complete_op(struct acpi_walk_state *walk_state,
union acpi_parse_object **op, acpi_status status)
@@ -719,6 +721,8 @@ acpi_ps_complete_op(struct acpi_walk_state *walk_state,
*op = NULL;
}
+ cond_resched();
+
return_ACPI_STATUS(AE_OK);
}
