Messages in this thread Patch in this message | | | Date | Wed, 23 Aug 2023 22:18:19 -0400 | From | Steven Rostedt <> | Subject | [for-next][PATCH 07/14] tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU |
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From: Valentin Schneider <vschneid@redhat.com>
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.
Link: https://lkml.kernel.org/r/20230707172155.70873-8-vschneid@redhat.com
Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Leonardo Bras <leobras@redhat.com> Cc: Frederic Weisbecker <frederic@kernel.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> --- 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 54d642fabb7f..fd72dacc5d1b 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); -- 2.40.1
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