diff options
| author | Valentin Schneider <vschneid@redhat.com> | 2023-07-07 18:21:51 +0100 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-08-22 05:13:28 -0400 |
| commit | fe4fa4ec9b464f5a93b2010247822fdd3a2a2115 (patch) | |
| tree | 7e161ead05604c19a91c9a51807222f03e26c72c /kernel/trace | |
| parent | 347d24fc8286e766696cfed112d6a353cb62cb68 (diff) | |
tracing/filters: Optimise cpumask vs cpumask filtering when user mask is a single CPU
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.
Reuse do_filter_scalar_cpumask() when the input mask has a weight of one.
Link: https://lkml.kernel.org/r/20230707172155.70873-6-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>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 3009d0c61b53..2fe65ddeb34e 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -70,6 +70,7 @@ enum filter_pred_fn { FILTER_PRED_FN_CPU, FILTER_PRED_FN_CPU_CPUMASK, FILTER_PRED_FN_CPUMASK, + FILTER_PRED_FN_CPUMASK_CPU, FILTER_PRED_FN_FUNCTION, FILTER_PRED_FN_, FILTER_PRED_TEST_VISITED, @@ -957,6 +958,22 @@ static int filter_pred_cpumask(struct filter_pred *pred, void *event) return do_filter_cpumask(pred->op, mask, cmp); } +/* Filter predicate for cpumask field vs user-provided scalar */ +static int filter_pred_cpumask_cpu(struct filter_pred *pred, void *event) +{ + u32 item = *(u32 *)(event + pred->offset); + int loc = item & 0xffff; + const struct cpumask *mask = (event + loc); + unsigned int cpu = pred->val; + + /* + * This inverts the usual usage of the function (field is first element, + * user parameter is second), but that's fine because the (scalar, mask) + * operations used are symmetric. + */ + return do_filter_scalar_cpumask(pred->op, cpu, mask); +} + /* Filter predicate for COMM. */ static int filter_pred_comm(struct filter_pred *pred, void *event) { @@ -1453,6 +1470,8 @@ static int filter_pred_fn_call(struct filter_pred *pred, void *event) return filter_pred_cpu_cpumask(pred, event); case FILTER_PRED_FN_CPUMASK: return filter_pred_cpumask(pred, event); + case FILTER_PRED_FN_CPUMASK_CPU: + return filter_pred_cpumask_cpu(pred, event); case FILTER_PRED_FN_FUNCTION: return filter_pred_function(pred, event); case FILTER_PRED_TEST_VISITED: @@ -1666,6 +1685,7 @@ static int parse_pred(const char *str, void *data, } else if (!strncmp(str + i, "CPUS", 4)) { unsigned int maskstart; + bool single; char *tmp; switch (field->filter_type) { @@ -1724,8 +1744,21 @@ static int parse_pred(const char *str, void *data, /* Move along */ i++; + + /* + * Optimisation: if the user-provided mask has a weight of one + * then we can treat it as a scalar input. + */ + single = cpumask_weight(pred->mask) == 1; + if (single && field->filter_type == FILTER_CPUMASK) { + pred->val = cpumask_first(pred->mask); + kfree(pred->mask); + } + if (field->filter_type == FILTER_CPUMASK) { - pred->fn_num = FILTER_PRED_FN_CPUMASK; + pred->fn_num = single ? + FILTER_PRED_FN_CPUMASK_CPU : + FILTER_PRED_FN_CPUMASK; } else if (field->filter_type == FILTER_CPU) { pred->fn_num = FILTER_PRED_FN_CPU_CPUMASK; } else { |