134 lines
4.5 KiB
Diff
134 lines
4.5 KiB
Diff
From: Tom Zanussi <tom.zanussi@linux.intel.com>
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Date: Mon, 26 Jun 2017 17:49:28 -0500
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Subject: [PATCH 27/32] tracing: Add cpu field for hist triggers
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.8-rt5.tar.xz
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A common key to use in a histogram is the cpuid - add a new cpu
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'synthetic' field for that purpose. This field is named cpu rather
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than $cpu or $common_cpu because 'cpu' already exists as a special
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filter field and it makes more sense to match that rather than add
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another name for the same thing.
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Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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Documentation/trace/events.txt | 18 ++++++++++++++++++
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kernel/trace/trace_events_hist.c | 30 +++++++++++++++++++++++++++---
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2 files changed, 45 insertions(+), 3 deletions(-)
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--- a/Documentation/trace/events.txt
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+++ b/Documentation/trace/events.txt
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@@ -668,6 +668,24 @@ triggers (you have to use '!' for each o
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The examples below provide a more concrete illustration of the
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concepts and typical usage patterns discussed above.
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+ 'synthetic' event fields
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+ ------------------------
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+
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+ There are a number of 'synthetic fields' available for use as keys
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+ or values in a hist trigger. These look like and behave as if they
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+ were event fields, but aren't actually part of the event's field
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+ definition or format file. They are however available for any
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+ event, and can be used anywhere an actual event field could be.
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+ 'Synthetic' field names are always prefixed with a '$' character to
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+ indicate that they're not normal fields (with the exception of
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+ 'cpu', for compatibility with existing filter usage):
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+
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+ $common_timestamp u64 - timestamp (from ring buffer) associated
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+ with the event, in nanoseconds. May be
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+ modified by .usecs to have timestamps
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+ interpreted as microseconds.
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+ cpu int - the cpu on which the event occurred.
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+
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6.2 'hist' trigger examples
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---------------------------
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--- a/kernel/trace/trace_events_hist.c
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+++ b/kernel/trace/trace_events_hist.c
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@@ -224,6 +224,7 @@ enum hist_field_flags {
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HIST_FIELD_FL_VAR_ONLY = 8192,
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HIST_FIELD_FL_EXPR = 16384,
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HIST_FIELD_FL_VAR_REF = 32768,
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+ HIST_FIELD_FL_CPU = 65536,
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};
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struct hist_trigger_attrs {
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@@ -1081,6 +1082,16 @@ static u64 hist_field_timestamp(struct h
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return ts;
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}
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+static u64 hist_field_cpu(struct hist_field *hist_field,
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+ struct tracing_map_elt *elt,
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+ struct ring_buffer_event *rbe,
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+ void *event)
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+{
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+ int cpu = raw_smp_processor_id();
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+
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+ return cpu;
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+}
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+
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static struct hist_field *check_var_ref(struct hist_field *hist_field,
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struct hist_trigger_data *var_data,
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unsigned int var_idx)
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@@ -1407,6 +1418,8 @@ static const char *hist_field_name(struc
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field_name = hist_field_name(field->operands[0], ++level);
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else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
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field_name = "$common_timestamp";
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+ else if (field->flags & HIST_FIELD_FL_CPU)
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+ field_name = "cpu";
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else if (field->flags & HIST_FIELD_FL_EXPR ||
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field->flags & HIST_FIELD_FL_VAR_REF)
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field_name = field->name;
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@@ -1848,6 +1861,15 @@ static struct hist_field *create_hist_fi
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goto out;
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}
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+ if (flags & HIST_FIELD_FL_CPU) {
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+ hist_field->fn = hist_field_cpu;
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+ hist_field->size = sizeof(int);
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+ hist_field->type = kstrdup("int", GFP_KERNEL);
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+ if (!hist_field->type)
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+ goto free;
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+ goto out;
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+ }
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+
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if (WARN_ON_ONCE(!field))
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goto out;
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@@ -1980,7 +2002,9 @@ parse_field(struct hist_trigger_data *hi
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hist_data->enable_timestamps = true;
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if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
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hist_data->attrs->ts_in_usecs = true;
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- } else {
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+ } else if (strcmp(field_name, "cpu") == 0)
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+ *flags |= HIST_FIELD_FL_CPU;
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+ else {
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field = trace_find_event_field(file->event_call, field_name);
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if (!field)
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return ERR_PTR(-EINVAL);
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@@ -3019,7 +3043,6 @@ static int onmatch_create(struct hist_tr
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goto out;
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}
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}
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-
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if (param[0] == '$')
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hist_field = onmatch_find_var(hist_data, data, system,
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event_name, param);
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@@ -3034,7 +3057,6 @@ static int onmatch_create(struct hist_tr
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ret = -EINVAL;
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goto out;
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}
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-
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if (check_synth_field(event, hist_field, field_pos) == 0) {
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var_ref = create_var_ref(hist_field);
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if (!var_ref) {
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@@ -4128,6 +4150,8 @@ static void hist_field_print(struct seq_
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if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
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seq_puts(m, "$common_timestamp");
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+ else if (hist_field->flags & HIST_FIELD_FL_CPU)
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+ seq_puts(m, "cpu");
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else if (field_name)
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seq_printf(m, "%s", field_name);
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