[PATCH v2 7/9] tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU
From: Valentin Schneider <vschneid@redhat.com>
Date: 2023-07-07 17:24:02
Also in:
linux-doc, lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
Steven noted that when the user-provided cpumask contains a single CPU, then the filtering function can use a scalar as input instead of a full-fledged cpumask. In this case we can directly re-use filter_pred_cpu(), we just need to transform '&' into '==' before executing it. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Valentin Schneider <vschneid@redhat.com> --- kernel/trace/trace_events_filter.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 54d642fabb7f1..fd72dacc5d1b8 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c@@ -1750,7 +1750,7 @@ static int parse_pred(const char *str, void *data, * then we can treat it as a scalar input. */ single = cpumask_weight(pred->mask) == 1; - if (single && field->filter_type != FILTER_CPU) { + if (single) { pred->val = cpumask_first(pred->mask); kfree(pred->mask); }
@@ -1760,7 +1760,12 @@ static int parse_pred(const char *str, void *data, FILTER_PRED_FN_CPUMASK_CPU : FILTER_PRED_FN_CPUMASK; } else if (field->filter_type == FILTER_CPU) { - pred->fn_num = FILTER_PRED_FN_CPU_CPUMASK; + if (single) { + pred->op = pred->op == OP_BAND ? OP_EQ : pred->op; + pred->fn_num = FILTER_PRED_FN_CPU; + } else { + pred->fn_num = FILTER_PRED_FN_CPU_CPUMASK; + } } else if (single) { pred->op = pred->op == OP_BAND ? OP_EQ : pred->op; pred->fn_num = select_comparison_fn(pred->op, field->size, false);
--
2.31.1