'hist' triggers add a 'hist' file to each event's subdirectory.
Reading the 'hist' file for the event will dump the hash table in
- its entirety to stdout. Each printed hash table entry is a simple
- list of the keys and values comprising the entry; keys are printed
- first and are delineated by curly braces, and are followed by the
- set of value fields for the entry. By default, numeric fields are
- displayed as base-10 integers. This can be modified by appending
- any of the following modifiers to the field name:
+ its entirety to stdout. If there are multiple hist triggers
+ attached to an event, there will be a table for each trigger in the
+ output. Each printed hash table entry is a simple list of the keys
+ and values comprising the entry; keys are printed first and are
+ delineated by curly braces, and are followed by the set of value
+ fields for the entry. By default, numeric fields are displayed as
+ base-10 integers. This can be modified by appending any of the
+ following modifiers to the field name:
.hex display a number as a hex value
.sym display an address as a symbol
.
.
.
+
+ The following example demonstrates how multiple hist triggers can be
+ attached to a given event. This capability can be useful for
+ creating a set of different summaries derived from the same set of
+ events, or for comparing the effects of different filters, among
+ other things.
+
+ # echo 'hist:keys=skbaddr.hex:vals=len if len < 0' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=skbaddr.hex:vals=len if len > 4096' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=skbaddr.hex:vals=len if len == 256' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=skbaddr.hex:vals=len' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=len:vals=common_preempt_count' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ The above set of commands create four triggers differing only in
+ their filters, along with a completely different though fairly
+ nonsensical trigger. Note that in order to append multiple hist
+ triggers to the same file, you should use the '>>' operator to
+ append them ('>' will also add the new hist trigger, but will remove
+ any existing hist triggers beforehand).
+
+ Displaying the contents of the 'hist' file for the event shows the
+ contents of all five histograms:
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
+
+ # event histogram
+ #
+ # trigger info: hist:keys=len:vals=hitcount,common_preempt_count:sort=hitcount:size=2048 [active]
+ #
+
+ { len: 176 } hitcount: 1 common_preempt_count: 0
+ { len: 223 } hitcount: 1 common_preempt_count: 0
+ { len: 4854 } hitcount: 1 common_preempt_count: 0
+ { len: 395 } hitcount: 1 common_preempt_count: 0
+ { len: 177 } hitcount: 1 common_preempt_count: 0
+ { len: 446 } hitcount: 1 common_preempt_count: 0
+ { len: 1601 } hitcount: 1 common_preempt_count: 0
+ .
+ .
+ .
+ { len: 1280 } hitcount: 66 common_preempt_count: 0
+ { len: 116 } hitcount: 81 common_preempt_count: 40
+ { len: 708 } hitcount: 112 common_preempt_count: 0
+ { len: 46 } hitcount: 221 common_preempt_count: 0
+ { len: 1264 } hitcount: 458 common_preempt_count: 0
+
+ Totals:
+ Hits: 1428
+ Entries: 147
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active]
+ #
+
+ { skbaddr: ffff8800baee5e00 } hitcount: 1 len: 130
+ { skbaddr: ffff88005f3d5600 } hitcount: 1 len: 1280
+ { skbaddr: ffff88005f3d4900 } hitcount: 1 len: 1280
+ { skbaddr: ffff88009fed6300 } hitcount: 1 len: 115
+ { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 115
+ { skbaddr: ffff88008cdb1900 } hitcount: 1 len: 46
+ { skbaddr: ffff880064b5ef00 } hitcount: 1 len: 118
+ { skbaddr: ffff880044e3c700 } hitcount: 1 len: 60
+ { skbaddr: ffff880100065900 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d46bd500 } hitcount: 1 len: 116
+ { skbaddr: ffff88005f3d5f00 } hitcount: 1 len: 1280
+ { skbaddr: ffff880100064700 } hitcount: 1 len: 365
+ { skbaddr: ffff8800badb6f00 } hitcount: 1 len: 60
+ .
+ .
+ .
+ { skbaddr: ffff88009fe0be00 } hitcount: 27 len: 24677
+ { skbaddr: ffff88009fe0a400 } hitcount: 27 len: 23052
+ { skbaddr: ffff88009fe0b700 } hitcount: 31 len: 25589
+ { skbaddr: ffff88009fe0b600 } hitcount: 32 len: 27326
+ { skbaddr: ffff88006a462800 } hitcount: 68 len: 71678
+ { skbaddr: ffff88006a463700 } hitcount: 70 len: 72678
+ { skbaddr: ffff88006a462b00 } hitcount: 71 len: 77589
+ { skbaddr: ffff88006a463600 } hitcount: 73 len: 71307
+ { skbaddr: ffff88006a462200 } hitcount: 81 len: 81032
+
+ Totals:
+ Hits: 1451
+ Entries: 318
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len == 256 [active]
+ #
+
+
+ Totals:
+ Hits: 0
+ Entries: 0
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len > 4096 [active]
+ #
+
+ { skbaddr: ffff88009fd2c300 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcce00 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcd700 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcda00 } hitcount: 1 len: 21492
+ { skbaddr: ffff8800ae2e2d00 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcdb00 } hitcount: 1 len: 7212
+ { skbaddr: ffff88006a4df500 } hitcount: 1 len: 4854
+ { skbaddr: ffff88008ce47b00 } hitcount: 1 len: 18636
+ { skbaddr: ffff8800ae2e2200 } hitcount: 1 len: 12924
+ { skbaddr: ffff88005f3e1000 } hitcount: 1 len: 4356
+ { skbaddr: ffff8800d2bcdc00 } hitcount: 2 len: 24420
+ { skbaddr: ffff8800d2bcc200 } hitcount: 2 len: 12996
+
+ Totals:
+ Hits: 14
+ Entries: 12
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len < 0 [active]
+ #
+
+
+ Totals:
+ Hits: 0
+ Entries: 0
+ Dropped: 0
return n_entries;
}
-static int hist_show(struct seq_file *m, void *v)
+static void hist_trigger_show(struct seq_file *m,
+ struct event_trigger_data *data, int n)
{
- struct event_trigger_data *test, *data = NULL;
- struct trace_event_file *event_file;
struct hist_trigger_data *hist_data;
int n_entries, ret = 0;
- mutex_lock(&event_mutex);
-
- event_file = event_file_data(m->private);
- if (unlikely(!event_file)) {
- ret = -ENODEV;
- goto out_unlock;
- }
-
- list_for_each_entry_rcu(test, &event_file->triggers, list) {
- if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
- data = test;
- break;
- }
- }
- if (!data)
- goto out_unlock;
+ if (n > 0)
+ seq_puts(m, "\n\n");
seq_puts(m, "# event histogram\n#\n# trigger info: ");
data->ops->print(m, data->ops, data);
- seq_puts(m, "\n");
+ seq_puts(m, "#\n\n");
hist_data = data->private_data;
n_entries = print_entries(m, hist_data);
seq_printf(m, "\nTotals:\n Hits: %llu\n Entries: %u\n Dropped: %llu\n",
(u64)atomic64_read(&hist_data->map->hits),
n_entries, (u64)atomic64_read(&hist_data->map->drops));
+}
+
+static int hist_show(struct seq_file *m, void *v)
+{
+ struct event_trigger_data *data;
+ struct trace_event_file *event_file;
+ int n = 0, ret = 0;
+
+ mutex_lock(&event_mutex);
+
+ event_file = event_file_data(m->private);
+ if (unlikely(!event_file)) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ list_for_each_entry_rcu(data, &event_file->triggers, list) {
+ if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
+ hist_trigger_show(m, data, n++);
+ }
+
out_unlock:
mutex_unlock(&event_mutex);
data->paused = paused;
}
+static bool hist_trigger_match(struct event_trigger_data *data,
+ struct event_trigger_data *data_test)
+{
+ struct tracing_map_sort_key *sort_key, *sort_key_test;
+ struct hist_trigger_data *hist_data, *hist_data_test;
+ struct hist_field *key_field, *key_field_test;
+ unsigned int i;
+
+ hist_data = data->private_data;
+ hist_data_test = data_test->private_data;
+
+ if (hist_data->n_vals != hist_data_test->n_vals ||
+ hist_data->n_fields != hist_data_test->n_fields ||
+ hist_data->n_sort_keys != hist_data_test->n_sort_keys)
+ return false;
+
+ if ((data->filter_str && !data_test->filter_str) ||
+ (!data->filter_str && data_test->filter_str))
+ return false;
+
+ for_each_hist_field(i, hist_data) {
+ key_field = hist_data->fields[i];
+ key_field_test = hist_data_test->fields[i];
+
+ if (key_field->flags != key_field_test->flags)
+ return false;
+ if (key_field->field != key_field_test->field)
+ return false;
+ if (key_field->offset != key_field_test->offset)
+ return false;
+ }
+
+ for (i = 0; i < hist_data->n_sort_keys; i++) {
+ sort_key = &hist_data->sort_keys[i];
+ sort_key_test = &hist_data_test->sort_keys[i];
+
+ if (sort_key->field_idx != sort_key_test->field_idx ||
+ sort_key->descending != sort_key_test->descending)
+ return false;
+ }
+
+ if (data->filter_str &&
+ (strcmp(data->filter_str, data_test->filter_str) != 0))
+ return false;
+
+ return true;
+}
+
static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
struct event_trigger_data *data,
struct trace_event_file *file)
list_for_each_entry_rcu(test, &file->triggers, list) {
if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ if (!hist_trigger_match(data, test))
+ continue;
if (hist_data->attrs->pause)
test->paused = true;
else if (hist_data->attrs->cont)
return ret;
}
+static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ struct event_trigger_data *test;
+ bool unregistered = false;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ if (!hist_trigger_match(data, test))
+ continue;
+ unregistered = true;
+ list_del_rcu(&test->list);
+ trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
+ break;
+ }
+ }
+
+ if (unregistered && test->ops->free)
+ test->ops->free(test->ops, test);
+}
+
+static void hist_unreg_all(struct trace_event_file *file)
+{
+ struct event_trigger_data *test;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ list_del_rcu(&test->list);
+ trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
+ if (test->ops->free)
+ test->ops->free(test->ops, test);
+ }
+ }
+}
+
static int event_hist_trigger_func(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param)
trigger_data->private_data = hist_data;
+ /* if param is non-empty, it's supposed to be a filter */
+ if (param && cmd_ops->set_filter) {
+ ret = cmd_ops->set_filter(param, trigger_data, file);
+ if (ret < 0)
+ goto out_free;
+ }
+
if (glob[0] == '!') {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
ret = 0;
goto out_free;
}
- if (!param) /* if param is non-empty, it's supposed to be a filter */
- goto out_reg;
-
- if (!cmd_ops->set_filter)
- goto out_reg;
-
- ret = cmd_ops->set_filter(param, trigger_data, file);
- if (ret < 0)
- goto out_free;
- out_reg:
ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
/*
* The above returns on success the # of triggers registered,
.flags = EVENT_CMD_FL_NEEDS_REC,
.func = event_hist_trigger_func,
.reg = hist_register_trigger,
- .unreg = unregister_trigger,
+ .unreg = hist_unregister_trigger,
+ .unreg_all = hist_unreg_all,
.get_trigger_ops = event_hist_get_trigger_ops,
.set_filter = set_trigger_filter,
};
test->paused = false;
else
test->paused = true;
- break;
}
}
}
return ops;
}
+static void hist_enable_unreg_all(struct trace_event_file *file)
+{
+ struct event_trigger_data *test;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
+ list_del_rcu(&test->list);
+ update_cond_flag(file);
+ trace_event_trigger_enable_disable(file, 0);
+ if (test->ops->free)
+ test->ops->free(test->ops, test);
+ }
+ }
+}
+
static struct event_command trigger_hist_enable_cmd = {
.name = ENABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
.func = event_enable_trigger_func,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
+ .unreg_all = hist_enable_unreg_all,
.get_trigger_ops = hist_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
.func = event_enable_trigger_func,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
+ .unreg_all = hist_enable_unreg_all,
.get_trigger_ops = hist_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
projects / users / willy / pagecache.git / commitdiff