perf: Add 'perf sched' tool

This turn-key tool allows scheduler measurements to be
conducted and the results be displayed numerically.

First baby step towards that goal: clone the new command off of
perf trace.

Fix a few other details along the way:

 - add (minimal) perf trace documentation

 - reorder a few places

 - list perf trace in the mainporcelain list as well
   as it's a very useful utility.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 297 insertions, 0 deletions

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
new file mode 100644
index 000000000000..60228d9179ac
--- /dev/null
+++ b/tools/perf/builtin-sched.c
@@ -0,0 +1,297 @@
+#include "builtin.h"
+
+#include "util/util.h"
+#include "util/cache.h"
+#include "util/symbol.h"
+#include "util/thread.h"
+#include "util/header.h"
+
+#include "util/parse-options.h"
+
+#include "perf.h"
+#include "util/debug.h"
+
+#include "util/trace-event.h"
+
+static char             const *input_name = "perf.data";
+static int              input;
+static unsigned long    page_size;
+static unsigned long    mmap_window = 32;
+
+static unsigned long    total = 0;
+static unsigned long    total_comm = 0;
+
+static struct rb_root   threads;
+static struct thread    *last_match;
+
+static struct perf_header *header;
+static u64              sample_type;
+
+
+static int
+process_comm_event(event_t *event, unsigned long offset, unsigned long head)
+{
+        struct thread *thread;
+
+        thread = threads__findnew(event->comm.pid, &threads, &last_match);
+
+        dump_printf("%p [%p]: PERF_EVENT_COMM: %s:%d\n",
+                (void *)(offset + head),
+                (void *)(long)(event->header.size),
+                event->comm.comm, event->comm.pid);
+
+        if (thread == NULL ||
+            thread__set_comm(thread, event->comm.comm)) {
+                dump_printf("problem processing PERF_EVENT_COMM, skipping event.\n");
+                return -1;
+        }
+        total_comm++;
+
+        return 0;
+}
+
+static int
+process_sample_event(event_t *event, unsigned long offset, unsigned long head)
+{
+        char level;
+        int show = 0;
+        struct dso *dso = NULL;
+        struct thread *thread;
+        u64 ip = event->ip.ip;
+        u64 timestamp = -1;
+        u32 cpu = -1;
+        u64 period = 1;
+        void *more_data = event->ip.__more_data;
+        int cpumode;
+
+        thread = threads__findnew(event->ip.pid, &threads, &last_match);
+
+        if (sample_type & PERF_SAMPLE_TIME) {
+                timestamp = *(u64 *)more_data;
+                more_data += sizeof(u64);
+        }
+
+        if (sample_type & PERF_SAMPLE_CPU) {
+                cpu = *(u32 *)more_data;
+                more_data += sizeof(u32);
+                more_data += sizeof(u32); /* reserved */
+        }
+
+        if (sample_type & PERF_SAMPLE_PERIOD) {
+                period = *(u64 *)more_data;
+                more_data += sizeof(u64);
+        }
+
+        dump_printf("%p [%p]: PERF_EVENT_SAMPLE (IP, %d): %d/%d: %p period: %Ld\n",
+                (void *)(offset + head),
+                (void *)(long)(event->header.size),
+                event->header.misc,
+                event->ip.pid, event->ip.tid,
+                (void *)(long)ip,
+                (long long)period);
+
+        dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
+
+        if (thread == NULL) {
+                eprintf("problem processing %d event, skipping it.\n",
+                        event->header.type);
+                return -1;
+        }
+
+        cpumode = event->header.misc & PERF_EVENT_MISC_CPUMODE_MASK;
+
+        if (cpumode == PERF_EVENT_MISC_KERNEL) {
+                show = SHOW_KERNEL;
+                level = 'k';
+
+                dso = kernel_dso;
+
+                dump_printf(" ...... dso: %s\n", dso->name);
+
+        } else if (cpumode == PERF_EVENT_MISC_USER) {
+
+                show = SHOW_USER;
+                level = '.';
+
+        } else {
+                show = SHOW_HV;
+                level = 'H';
+
+                dso = hypervisor_dso;
+
+                dump_printf(" ...... dso: [hypervisor]\n");
+        }
+
+        if (sample_type & PERF_SAMPLE_RAW) {
+                struct {
+                        u32 size;
+                        char data[0];
+                } *raw = more_data;
+
+                /*
+                 * FIXME: better resolve from pid from the struct trace_entry
+                 * field, although it should be the same than this perf
+                 * event pid
+                 */
+                print_event(cpu, raw->data, raw->size, timestamp, thread->comm);
+        }
+        total += period;
+
+        return 0;
+}
+
+static int
+process_event(event_t *event, unsigned long offset, unsigned long head)
+{
+        trace_event(event);
+
+        switch (event->header.type) {
+        case PERF_EVENT_MMAP ... PERF_EVENT_LOST:
+                return 0;
+
+        case PERF_EVENT_COMM:
+                return process_comm_event(event, offset, head);
+
+        case PERF_EVENT_EXIT ... PERF_EVENT_READ:
+                return 0;
+
+        case PERF_EVENT_SAMPLE:
+                return process_sample_event(event, offset, head);
+
+        case PERF_EVENT_MAX:
+        default:
+                return -1;
+        }
+
+        return 0;
+}
+
+static int __cmd_sched(void)
+{
+        int ret, rc = EXIT_FAILURE;
+        unsigned long offset = 0;
+        unsigned long head = 0;
+        struct stat perf_stat;
+        event_t *event;
+        uint32_t size;
+        char *buf;
+
+        trace_report();
+        register_idle_thread(&threads, &last_match);
+
+        input = open(input_name, O_RDONLY);
+        if (input < 0) {
+                perror("failed to open file");
+                exit(-1);
+        }
+
+        ret = fstat(input, &perf_stat);
+        if (ret < 0) {
+                perror("failed to stat file");
+                exit(-1);
+        }
+
+        if (!perf_stat.st_size) {
+                fprintf(stderr, "zero-sized file, nothing to do!\n");
+                exit(0);
+        }
+        header = perf_header__read(input);
+        head = header->data_offset;
+        sample_type = perf_header__sample_type(header);
+
+        if (!(sample_type & PERF_SAMPLE_RAW))
+                die("No trace sample to read. Did you call perf record "
+                    "without -R?");
+
+        if (load_kernel() < 0) {
+                perror("failed to load kernel symbols");
+                return EXIT_FAILURE;
+        }
+
+remap:
+        buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
+                           MAP_SHARED, input, offset);
+        if (buf == MAP_FAILED) {
+                perror("failed to mmap file");
+                exit(-1);
+        }
+
+more:
+        event = (event_t *)(buf + head);
+
+        size = event->header.size;
+        if (!size)
+                size = 8;
+
+        if (head + event->header.size >= page_size * mmap_window) {
+                unsigned long shift = page_size * (head / page_size);
+                int res;
+
+                res = munmap(buf, page_size * mmap_window);
+                assert(res == 0);
+
+                offset += shift;
+                head -= shift;
+                goto remap;
+        }
+
+        size = event->header.size;
+
+
+        if (!size || process_event(event, offset, head) < 0) {
+
+                /*
+                 * assume we lost track of the stream, check alignment, and
+                 * increment a single u64 in the hope to catch on again 'soon'.
+                 */
+
+                if (unlikely(head & 7))
+                        head &= ~7ULL;
+
+                size = 8;
+        }
+
+        head += size;
+
+        if (offset + head < (unsigned long)perf_stat.st_size)
+                goto more;
+
+        rc = EXIT_SUCCESS;
+        close(input);
+
+        return rc;
+}
+
+static const char * const annotate_usage[] = {
+        "perf trace [<options>] <command>",
+        NULL
+};
+
+static const struct option options[] = {
+        OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
+                    "dump raw trace in ASCII"),
+        OPT_BOOLEAN('v', "verbose", &verbose,
+                    "be more verbose (show symbol address, etc)"),
+        OPT_END()
+};
+
+int cmd_sched(int argc, const char **argv, const char *prefix __used)
+{
+        symbol__init();
+        page_size = getpagesize();
+
+        argc = parse_options(argc, argv, options, annotate_usage, 0);
+        if (argc) {
+                /*
+                 * Special case: if there's an argument left then assume tha
+                 * it's a symbol filter:
+                 */
+                if (argc > 1)
+                        usage_with_options(annotate_usage, options);
+        }
+
+
+        setup_pager();
+
+        return __cmd_sched();
+}