auxtrace.c

  1#include <errno.h>
  2#include <stdbool.h>
  3#include <stdlib.h>
  4#include <linux/kernel.h>
  5#include <linux/types.h>
  6#include <linux/bitops.h>
  7#include <linux/log2.h>
  8#include <linux/zalloc.h>
  9
 10#include "../../util/evlist.h"
 11#include "../../util/auxtrace.h"
 12#include "../../util/evsel.h"
 13#include "../../util/record.h"
 14
 15#define PERF_EVENT_CPUM_SF		0xB0000 /* Event: Basic-sampling */
 16#define PERF_EVENT_CPUM_SF_DIAG		0xBD000 /* Event: Combined-sampling */
 17#define DEFAULT_AUX_PAGES		128
 18#define DEFAULT_FREQ			4000
 19
 20static void cpumsf_free(struct auxtrace_record *itr)
 21{
 22	free(itr);
 23}
 24
 25static size_t cpumsf_info_priv_size(struct auxtrace_record *itr __maybe_unused,
 26				    struct evlist *evlist __maybe_unused)
 27{
 28	return 0;
 29}
 30
 31static int
 32cpumsf_info_fill(struct auxtrace_record *itr __maybe_unused,
 33		 struct perf_session *session __maybe_unused,
 34		 struct perf_record_auxtrace_info *auxtrace_info __maybe_unused,
 35		 size_t priv_size __maybe_unused)
 36{
 37	auxtrace_info->type = PERF_AUXTRACE_S390_CPUMSF;
 38	return 0;
 39}
 40
 41static unsigned long
 42cpumsf_reference(struct auxtrace_record *itr __maybe_unused)
 43{
 44	return 0;
 45}
 46
 47static int
 48cpumsf_recording_options(struct auxtrace_record *ar __maybe_unused,
 49			 struct evlist *evlist __maybe_unused,
 50			 struct record_opts *opts)
 51{
 52	unsigned int factor = 1;
 53	unsigned int pages;
 54
 55	opts->full_auxtrace = true;
 56
 57	/*
 58	 * The AUX buffer size should be set properly to avoid
 59	 * overflow of samples if it is not set explicitly.
 60	 * DEFAULT_AUX_PAGES is an proper size when sampling frequency
 61	 * is DEFAULT_FREQ. It is expected to hold about 1/2 second
 62	 * of sampling data. The size used for AUX buffer will scale
 63	 * according to the specified frequency and DEFAULT_FREQ.
 64	 */
 65	if (!opts->auxtrace_mmap_pages) {
 66		if (opts->user_freq != UINT_MAX)
 67			factor = (opts->user_freq + DEFAULT_FREQ
 68				  - 1) / DEFAULT_FREQ;
 69		pages = DEFAULT_AUX_PAGES * factor;
 70		opts->auxtrace_mmap_pages = roundup_pow_of_two(pages);
 71	}
 72
 73	return 0;
 74}
 75
 76static int
 77cpumsf_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
 78			      struct record_opts *opts __maybe_unused,
 79			      const char *str __maybe_unused)
 80{
 81	return 0;
 82}
 83
 84/*
 85 * auxtrace_record__init is called when perf record
 86 * check if the event really need auxtrace
 87 */
 88struct auxtrace_record *auxtrace_record__init(struct evlist *evlist,
 89					      int *err)
 90{
 91	struct auxtrace_record *aux;
 92	struct evsel *pos;
 93	int diagnose = 0;
 94
 95	*err = 0;
 96	if (evlist->core.nr_entries == 0)
 97		return NULL;
 98
 99	evlist__for_each_entry(evlist, pos) {
100		if (pos->core.attr.config == PERF_EVENT_CPUM_SF_DIAG) {
101			diagnose = 1;
102			pos->needs_auxtrace_mmap = true;
103			break;
104		}
105	}
106
107	if (!diagnose)
108		return NULL;
109
110	/* sampling in diagnose mode. alloc aux buffer */
111	aux = zalloc(sizeof(*aux));
112	if (aux == NULL) {
113		*err = -ENOMEM;
114		return NULL;
115	}
116
117	aux->parse_snapshot_options = cpumsf_parse_snapshot_options;
118	aux->recording_options = cpumsf_recording_options;
119	aux->info_priv_size = cpumsf_info_priv_size;
120	aux->info_fill = cpumsf_info_fill;
121	aux->free = cpumsf_free;
122	aux->reference = cpumsf_reference;
123
124	return aux;
125}