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authorSteven Rostedt <srostedt@redhat.com>2011-01-27 23:16:51 -0500
committerSteven Rostedt <rostedt@goodmis.org>2011-02-07 20:56:19 -0500
commit43cd414552d8137157e926e46361678ea867e476 (patch)
treecbb50e071a8149e2da7be995166f487bbcb5172a /kernel/trace/trace.h
parentec126cac23945de12eb2d103374e1f7ee97c5595 (diff)
tracing/filter: Optimize filter by folding the tree
There are many cases that a filter will contain multiple ORs or ANDs together near the leafs. Walking up and down the tree to get to the next compare can be a waste. If there are several ORs or ANDs together, fold them into a single pred and allocate an array of the conditions that they check. This will speed up the filter by linearly walking an array and can still break out if a short circuit condition is met. Cc: Tom Zanussi <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r--kernel/trace/trace.h12
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index bba34a72c780..d754330934bb 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -678,6 +678,7 @@ struct event_subsystem {
#define FILTER_PRED_INVALID ((unsigned short)-1)
#define FILTER_PRED_IS_RIGHT (1 << 15)
+#define FILTER_PRED_FOLD (1 << 15)
struct filter_pred;
struct regex;
@@ -704,7 +705,16 @@ struct filter_pred {
filter_pred_fn_t fn;
u64 val;
struct regex regex;
- char *field_name;
+ /*
+ * Leaf nodes use field_name, ops is used by AND and OR
+ * nodes. The field_name is always freed when freeing a pred.
+ * We can overload field_name for ops and have it freed
+ * as well.
+ */
+ union {
+ char *field_name;
+ unsigned short *ops;
+ };
int offset;
int not;
int op;