perf_counter: some simple userspace profiling

# perf-record make -j4 kernel/
 # perf-report | tail -15

  0.39              cc1 [kernel] lock_acquired
  0.42              cc1 [kernel] lock_acquire
  0.51              cc1 [ user ] /lib64/libc-2.8.90.so: _int_free
  0.51               as [kernel] clear_page_c
  0.53              cc1 [ user ] /lib64/libc-2.8.90.so: memcpy
  0.56              cc1 [ user ] /lib64/libc-2.8.90.so: _IO_vfprintf
  0.63              cc1 [kernel] lock_release
  0.67              cc1 [ user ] /lib64/libc-2.8.90.so: strlen
  0.68              cc1 [kernel] debug_smp_processor_id
  1.38              cc1 [ user ] /lib64/libc-2.8.90.so: _int_malloc
  1.55              cc1 [ user ] /lib64/libc-2.8.90.so: memset
  1.77              cc1 [kernel] __lock_acquire
  1.88              cc1 [kernel] clear_page_c
  3.61               as [ user ] /usr/bin/as: <unknown>
 59.16              cc1 [ user ] /usr/libexec/gcc/x86_64-redhat-linux/4.3.2/cc1: <unknown>

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
LKML-Reference: <20090408130409.220518450@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 1009 insertions, 1 deletions

diff --git a/Documentation/perf_counter/Makefile b/Documentation/perf_counter/Makefile
index 194b66215588..1dd37ee7dbdc 100644
--- a/Documentation/perf_counter/Makefile
+++ b/Documentation/perf_counter/Makefile
@@ -1,10 +1,16 @@
-BINS = kerneltop perfstat
+BINS = kerneltop perfstat perf-record perf-report
 
 all: $(BINS)
 
 kerneltop: kerneltop.c ../../include/linux/perf_counter.h
         cc -O6 -Wall -lrt -o $@ $<
 
+perf-record: perf-record.c ../../include/linux/perf_counter.h
+        cc -O6 -Wall -lrt -o $@ $<
+
+perf-report: perf-report.cc ../../include/linux/perf_counter.h
+        g++ -O6 -Wall -lrt -o $@ $<
+
 perfstat: kerneltop
         ln -sf kerneltop perfstat
 
diff --git a/Documentation/perf_counter/perf-record.c b/Documentation/perf_counter/perf-record.c
new file mode 100644
index 000000000000..614de7c468b2
--- /dev/null
+++ b/Documentation/perf_counter/perf-record.c
@@ -0,0 +1,530 @@
+
+
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <getopt.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <time.h>
+#include <sched.h>
+#include <pthread.h>
+
+#include <sys/syscall.h>
+#include <sys/ioctl.h>
+#include <sys/poll.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+
+#include <linux/unistd.h>
+#include <linux/types.h>
+
+#include "../../include/linux/perf_counter.h"
+
+
+/*
+ * prctl(PR_TASK_PERF_COUNTERS_DISABLE) will (cheaply) disable all
+ * counters in the current task.
+ */
+#define PR_TASK_PERF_COUNTERS_DISABLE   31
+#define PR_TASK_PERF_COUNTERS_ENABLE    32
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+#define rdclock()                                       \
+({                                                      \
+        struct timespec ts;                             \
+                                                        \
+        clock_gettime(CLOCK_MONOTONIC, &ts);            \
+        ts.tv_sec * 1000000000ULL + ts.tv_nsec;         \
+})
+
+/*
+ * Pick up some kernel type conventions:
+ */
+#define __user
+#define asmlinkage
+
+#ifdef __x86_64__
+#define __NR_perf_counter_open 295
+#define rmb()           asm volatile("lfence" ::: "memory")
+#define cpu_relax()     asm volatile("rep; nop" ::: "memory");
+#endif
+
+#ifdef __i386__
+#define __NR_perf_counter_open 333
+#define rmb()           asm volatile("lfence" ::: "memory")
+#define cpu_relax()     asm volatile("rep; nop" ::: "memory");
+#endif
+
+#ifdef __powerpc__
+#define __NR_perf_counter_open 319
+#define rmb()           asm volatile ("sync" ::: "memory")
+#define cpu_relax()     asm volatile ("" ::: "memory");
+#endif
+
+#define unlikely(x)     __builtin_expect(!!(x), 0)
+#define min(x, y) ({                            \
+        typeof(x) _min1 = (x);                  \
+        typeof(y) _min2 = (y);                  \
+        (void) (&_min1 == &_min2);              \
+        _min1 < _min2 ? _min1 : _min2; })
+
+asmlinkage int sys_perf_counter_open(
+        struct perf_counter_hw_event    *hw_event_uptr          __user,
+        pid_t                           pid,
+        int                             cpu,
+        int                             group_fd,
+        unsigned long                   flags)
+{
+        return syscall(
+                __NR_perf_counter_open, hw_event_uptr, pid, cpu, group_fd, flags);
+}
+
+#define MAX_COUNTERS                    64
+#define MAX_NR_CPUS                     256
+
+#define EID(type, id) (((__u64)(type) << PERF_COUNTER_TYPE_SHIFT) | (id))
+
+static int                      nr_counters                     =  0;
+static __u64                    event_id[MAX_COUNTERS]          = { };
+static int                      default_interval = 100000;
+static int                      event_count[MAX_COUNTERS];
+static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
+static int                      nr_cpus                         =  0;
+static unsigned int             page_size;
+static unsigned int             mmap_pages                      = 16;
+static int                      output;
+static char                     *output_name                    = "output.perf";
+static int                      group                           = 0;
+static unsigned int             realtime_prio                   =  0;
+
+const unsigned int default_count[] = {
+        1000000,
+        1000000,
+          10000,
+          10000,
+        1000000,
+          10000,
+};
+
+static char *hw_event_names[] = {
+        "CPU cycles",
+        "instructions",
+        "cache references",
+        "cache misses",
+        "branches",
+        "branch misses",
+        "bus cycles",
+};
+
+static char *sw_event_names[] = {
+        "cpu clock ticks",
+        "task clock ticks",
+        "pagefaults",
+        "context switches",
+        "CPU migrations",
+        "minor faults",
+        "major faults",
+};
+
+struct event_symbol {
+        __u64 event;
+        char *symbol;
+};
+
+static struct event_symbol event_symbols[] = {
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_CPU_CYCLES),                "cpu-cycles",           },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_CPU_CYCLES),                "cycles",               },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_INSTRUCTIONS),              "instructions",         },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_CACHE_REFERENCES),          "cache-references",     },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_CACHE_MISSES),              "cache-misses",         },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_BRANCH_INSTRUCTIONS),       "branch-instructions",  },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_BRANCH_INSTRUCTIONS),       "branches",             },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_BRANCH_MISSES),             "branch-misses",        },
+        {EID(PERF_TYPE_HARDWARE, PERF_COUNT_BUS_CYCLES),                "bus-cycles",           },
+
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CPU_CLOCK),                 "cpu-clock",            },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_TASK_CLOCK),                "task-clock",           },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_PAGE_FAULTS),               "page-faults",          },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_PAGE_FAULTS),               "faults",               },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_PAGE_FAULTS_MIN),           "minor-faults",         },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_PAGE_FAULTS_MAJ),           "major-faults",         },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CONTEXT_SWITCHES),          "context-switches",     },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CONTEXT_SWITCHES),          "cs",                   },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CPU_MIGRATIONS),            "cpu-migrations",       },
+        {EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CPU_MIGRATIONS),            "migrations",           },
+};
+
+/*
+ * Each event can have multiple symbolic names.
+ * Symbolic names are (almost) exactly matched.
+ */
+static __u64 match_event_symbols(char *str)
+{
+        __u64 config, id;
+        int type;
+        unsigned int i;
+
+        if (sscanf(str, "r%llx", &config) == 1)
+                return config | PERF_COUNTER_RAW_MASK;
+
+        if (sscanf(str, "%d:%llu", &type, &id) == 2)
+                return EID(type, id);
+
+        for (i = 0; i < ARRAY_SIZE(event_symbols); i++) {
+                if (!strncmp(str, event_symbols[i].symbol,
+                             strlen(event_symbols[i].symbol)))
+                        return event_symbols[i].event;
+        }
+
+        return ~0ULL;
+}
+
+static int parse_events(char *str)
+{
+        __u64 config;
+
+again:
+        if (nr_counters == MAX_COUNTERS)
+                return -1;
+
+        config = match_event_symbols(str);
+        if (config == ~0ULL)
+                return -1;
+
+        event_id[nr_counters] = config;
+        nr_counters++;
+
+        str = strstr(str, ",");
+        if (str) {
+                str++;
+                goto again;
+        }
+
+        return 0;
+}
+
+#define __PERF_COUNTER_FIELD(config, name) \
+        ((config & PERF_COUNTER_##name##_MASK) >> PERF_COUNTER_##name##_SHIFT)
+
+#define PERF_COUNTER_RAW(config)        __PERF_COUNTER_FIELD(config, RAW)
+#define PERF_COUNTER_CONFIG(config)     __PERF_COUNTER_FIELD(config, CONFIG)
+#define PERF_COUNTER_TYPE(config)       __PERF_COUNTER_FIELD(config, TYPE)
+#define PERF_COUNTER_ID(config)         __PERF_COUNTER_FIELD(config, EVENT)
+
+static void display_events_help(void)
+{
+        unsigned int i;
+        __u64 e;
+
+        printf(
+        " -e EVENT     --event=EVENT   #  symbolic-name        abbreviations");
+
+        for (i = 0; i < ARRAY_SIZE(event_symbols); i++) {
+                int type, id;
+
+                e = event_symbols[i].event;
+                type = PERF_COUNTER_TYPE(e);
+                id = PERF_COUNTER_ID(e);
+
+                printf("\n                             %d:%d: %-20s",
+                                type, id, event_symbols[i].symbol);
+        }
+
+        printf("\n"
+        "                           rNNN: raw PMU events (eventsel+umask)\n\n");
+}
+
+static void display_help(void)
+{
+        printf(
+        "Usage: perf-record [<options>]\n"
+        "perf-record Options (up to %d event types can be specified at once):\n\n",
+                 MAX_COUNTERS);
+
+        display_events_help();
+
+        printf(
+        " -c CNT    --count=CNT          # event period to sample\n"
+        " -m pages  --mmap_pages=<pages> # number of mmap data pages\n"
+        " -o file   --output=<file>      # output file\n"
+        " -r prio   --realtime=<prio>    # use RT prio\n"
+        );
+
+        exit(0);
+}
+
+static void process_options(int argc, char *argv[])
+{
+        int error = 0, counter;
+
+        for (;;) {
+                int option_index = 0;
+                /** Options for getopt */
+                static struct option long_options[] = {
+                        {"count",       required_argument,      NULL, 'c'},
+                        {"event",       required_argument,      NULL, 'e'},
+                        {"mmap_pages",  required_argument,      NULL, 'm'},
+                        {"output",      required_argument,      NULL, 'o'},
+                        {"realtime",    required_argument,      NULL, 'r'},
+                        {NULL,          0,                      NULL,  0 }
+                };
+                int c = getopt_long(argc, argv, "+:c:e:m:o:r:",
+                                    long_options, &option_index);
+                if (c == -1)
+                        break;
+
+                switch (c) {
+                case 'c': default_interval              =   atoi(optarg); break;
+                case 'e': error                         = parse_events(optarg); break;
+                case 'm': mmap_pages                    =   atoi(optarg); break;
+                case 'o': output_name                   = strdup(optarg); break;
+                case 'r': realtime_prio                 =   atoi(optarg); break;
+                default: error = 1; break;
+                }
+        }
+        if (error)
+                display_help();
+
+        if (!nr_counters) {
+                nr_counters = 1;
+                event_id[0] = 0;
+        }
+
+        for (counter = 0; counter < nr_counters; counter++) {
+                if (event_count[counter])
+                        continue;
+
+                event_count[counter] = default_interval;
+        }
+}
+
+struct mmap_data {
+        int counter;
+        void *base;
+        unsigned int mask;
+        unsigned int prev;
+};
+
+static unsigned int mmap_read_head(struct mmap_data *md)
+{
+        struct perf_counter_mmap_page *pc = md->base;
+        int head;
+
+        head = pc->data_head;
+        rmb();
+
+        return head;
+}
+
+static long events;
+static struct timeval last_read, this_read;
+
+static void mmap_read(struct mmap_data *md)
+{
+        unsigned int head = mmap_read_head(md);
+        unsigned int old = md->prev;
+        unsigned char *data = md->base + page_size;
+        unsigned long size;
+        void *buf;
+        int diff;
+
+        gettimeofday(&this_read, NULL);
+
+        /*
+         * If we're further behind than half the buffer, there's a chance
+         * the writer will bite our tail and screw up the events under us.
+         *
+         * If we somehow ended up ahead of the head, we got messed up.
+         *
+         * In either case, truncate and restart at head.
+         */
+        diff = head - old;
+        if (diff > md->mask / 2 || diff < 0) {
+                struct timeval iv;
+                unsigned long msecs;
+
+                timersub(&this_read, &last_read, &iv);
+                msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
+
+                fprintf(stderr, "WARNING: failed to keep up with mmap data."
+                                "  Last read %lu msecs ago.\n", msecs);
+
+                /*
+                 * head points to a known good entry, start there.
+                 */
+                old = head;
+        }
+
+        last_read = this_read;
+
+        if (old != head)
+                events++;
+
+        size = head - old;
+
+        if ((old & md->mask) + size != (head & md->mask)) {
+                buf = &data[old & md->mask];
+                size = md->mask + 1 - (old & md->mask);
+                old += size;
+                while (size) {
+                        int ret = write(output, buf, size);
+                        if (ret < 0) {
+                                perror("failed to write");
+                                exit(-1);
+                        }
+                        size -= ret;
+                        buf += ret;
+                }
+        }
+
+        buf = &data[old & md->mask];
+        size = head - old;
+        old += size;
+        while (size) {
+                int ret = write(output, buf, size);
+                if (ret < 0) {
+                        perror("failed to write");
+                        exit(-1);
+                }
+                size -= ret;
+                buf += ret;
+        }
+
+        md->prev = old;
+}
+
+static volatile int done = 0;
+
+static void sigchld_handler(int sig)
+{
+        if (sig == SIGCHLD)
+                done = 1;
+}
+
+int main(int argc, char *argv[])
+{
+        struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
+        struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
+        struct perf_counter_hw_event hw_event;
+        int i, counter, group_fd, nr_poll = 0;
+        pid_t pid;
+        int ret;
+
+        page_size = sysconf(_SC_PAGE_SIZE);
+
+        process_options(argc, argv);
+
+        nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+        assert(nr_cpus <= MAX_NR_CPUS);
+        assert(nr_cpus >= 0);
+
+        output = open(output_name, O_CREAT|O_RDWR, S_IRWXU);
+        if (output < 0) {
+                perror("failed to create output file");
+                exit(-1);
+        }
+
+        argc -= optind;
+        argv += optind;
+
+        for (i = 0; i < nr_cpus; i++) {
+                group_fd = -1;
+                for (counter = 0; counter < nr_counters; counter++) {
+
+                        memset(&hw_event, 0, sizeof(hw_event));
+                        hw_event.config         = event_id[counter];
+                        hw_event.irq_period     = event_count[counter];
+                        hw_event.record_type    = PERF_RECORD_IP | PERF_RECORD_TID;
+                        hw_event.nmi            = 1;
+                        hw_event.mmap           = 1;
+                        hw_event.comm           = 1;
+
+                        fd[i][counter] = sys_perf_counter_open(&hw_event, -1, i, group_fd, 0);
+                        if (fd[i][counter] < 0) {
+                                int err = errno;
+                                printf("kerneltop error: syscall returned with %d (%s)\n",
+                                        fd[i][counter], strerror(err));
+                                if (err == EPERM)
+                                        printf("Are you root?\n");
+                                exit(-1);
+                        }
+                        assert(fd[i][counter] >= 0);
+                        fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);
+
+                        /*
+                         * First counter acts as the group leader:
+                         */
+                        if (group && group_fd == -1)
+                                group_fd = fd[i][counter];
+
+                        event_array[nr_poll].fd = fd[i][counter];
+                        event_array[nr_poll].events = POLLIN;
+                        nr_poll++;
+
+                        mmap_array[i][counter].counter = counter;
+                        mmap_array[i][counter].prev = 0;
+                        mmap_array[i][counter].mask = mmap_pages*page_size - 1;
+                        mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
+                                        PROT_READ, MAP_SHARED, fd[i][counter], 0);
+                        if (mmap_array[i][counter].base == MAP_FAILED) {
+                                printf("kerneltop error: failed to mmap with %d (%s)\n",
+                                                errno, strerror(errno));
+                                exit(-1);
+                        }
+                }
+        }
+
+        signal(SIGCHLD, sigchld_handler);
+
+        pid = fork();
+        if (pid < 0)
+                perror("failed to fork");
+
+        if (!pid) {
+                if (execvp(argv[0], argv)) {
+                        perror(argv[0]);
+                        exit(-1);
+                }
+        }
+
+        if (realtime_prio) {
+                struct sched_param param;
+
+                param.sched_priority = realtime_prio;
+                if (sched_setscheduler(0, SCHED_FIFO, &param)) {
+                        printf("Could not set realtime priority.\n");
+                        exit(-1);
+                }
+        }
+
+        /*
+         * TODO: store the current /proc/$/maps information somewhere
+         */
+
+        while (!done) {
+                int hits = events;
+
+                for (i = 0; i < nr_cpus; i++) {
+                        for (counter = 0; counter < nr_counters; counter++)
+                                mmap_read(&mmap_array[i][counter]);
+                }
+
+                if (hits == events)
+                        ret = poll(event_array, nr_poll, 100);
+        }
+
+        return 0;
+}
diff --git a/Documentation/perf_counter/perf-report.cc b/Documentation/perf_counter/perf-report.cc
new file mode 100644
index 000000000000..09da0ba482cd
--- /dev/null
+++ b/Documentation/perf_counter/perf-report.cc
@@ -0,0 +1,472 @@
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <time.h>
+#include <getopt.h>
+
+#include <sys/ioctl.h>
+#include <sys/poll.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <linux/unistd.h>
+#include <linux/types.h>
+
+#include "../../include/linux/perf_counter.h"
+
+#include <set>
+#include <map>
+#include <string>
+
+
+static char             const *input_name = "output.perf";
+static int              input;
+
+static unsigned long    page_size;
+static unsigned long    mmap_window = 32;
+
+struct ip_event {
+        struct perf_event_header header;
+        __u64 ip;
+        __u32 pid, tid;
+};
+struct mmap_event {
+        struct perf_event_header header;
+        __u32 pid, tid;
+        __u64 start;
+        __u64 len;
+        __u64 pgoff;
+        char filename[PATH_MAX];
+};
+struct comm_event {
+        struct perf_event_header header;
+        __u32 pid,tid;
+        char comm[16];
+};
+
+typedef union event_union {
+        struct perf_event_header header;
+        struct ip_event ip;
+        struct mmap_event mmap;
+        struct comm_event comm;
+} event_t;
+
+struct section {
+        uint64_t start;
+        uint64_t end;
+
+        uint64_t offset;
+
+        std::string name;
+
+        section() { };
+
+        section(uint64_t stab) : end(stab) { };
+
+        section(uint64_t start, uint64_t size, uint64_t offset, std::string name) :
+                start(start), end(start + size), offset(offset), name(name)
+        { };
+
+        bool operator < (const struct section &s) const {
+                return end < s.end;
+        };
+};
+
+typedef std::set<struct section> sections_t;
+
+struct symbol {
+        uint64_t start;
+        uint64_t end;
+
+        std::string name;
+
+        symbol() { };
+
+        symbol(uint64_t ip) : start(ip) { }
+
+        symbol(uint64_t start, uint64_t len, std::string name) :
+                start(start), end(start + len), name(name)
+        { };
+
+        bool operator < (const struct symbol &s) const {
+                return start < s.start;
+        };
+};
+
+typedef std::set<struct symbol> symbols_t;
+
+struct dso {
+        sections_t sections;
+        symbols_t syms;
+};
+
+static std::map<std::string, struct dso> dsos;
+
+static void load_dso_sections(std::string dso_name)
+{
+        struct dso &dso = dsos[dso_name];
+
+        std::string cmd = "readelf -DSW " + dso_name;
+
+        FILE *file = popen(cmd.c_str(), "r");
+        if (!file) {
+                perror("failed to open pipe");
+                exit(-1);
+        }
+
+        char *line = NULL;
+        size_t n = 0;
+
+        while (!feof(file)) {
+                uint64_t addr, off, size;
+                char name[32];
+
+                if (getline(&line, &n, file) < 0)
+                        break;
+                if (!line)
+                        break;
+
+                if (sscanf(line, "  [%*2d] %16s %*14s %Lx %Lx %Lx",
+                                        name, &addr, &off, &size) == 4) {
+
+                        dso.sections.insert(section(addr, size, addr - off, name));
+                }
+#if 0
+                /*
+                 * for reading readelf symbols (-s), however these don't seem
+                 * to include nearly everything, so use nm for that.
+                 */
+                if (sscanf(line, " %*4d %*3d: %Lx %5Lu %*7s %*6s %*7s %3d %s",
+                           &start, &size, &section, sym) == 4) {
+
+                        start -= dso.section_offsets[section];
+
+                        dso.syms.insert(symbol(start, size, std::string(sym)));
+                }
+#endif
+        }
+        pclose(file);
+}
+
+static void load_dso_symbols(std::string dso_name, std::string args)
+{
+        struct dso &dso = dsos[dso_name];
+
+        std::string cmd = "nm -nSC " + args + " " + dso_name;
+
+        FILE *file = popen(cmd.c_str(), "r");
+        if (!file) {
+                perror("failed to open pipe");
+                exit(-1);
+        }
+
+        char *line = NULL;
+        size_t n = 0;
+
+        while (!feof(file)) {
+                uint64_t start, size;
+                char c;
+                char sym[1024];
+
+                if (getline(&line, &n, file) < 0)
+                        break;
+                if (!line)
+                        break;
+
+
+                if (sscanf(line, "%Lx %Lx %c %s", &start, &size, &c, sym) == 4) {
+                        sections_t::const_iterator si =
+                                dso.sections.upper_bound(section(start));
+                        if (si == dso.sections.end()) {
+                                printf("symbol in unknown section: %s\n", sym);
+                                continue;
+                        }
+
+                        start -= si->offset;
+
+                        dso.syms.insert(symbol(start, size, sym));
+                }
+        }
+        pclose(file);
+}
+
+static void load_dso(std::string dso_name)
+{
+        load_dso_sections(dso_name);
+        load_dso_symbols(dso_name, "-D"); /* dynamic symbols */
+        load_dso_symbols(dso_name, "");   /* regular ones */
+}
+
+void load_kallsyms(void)
+{
+        struct dso &dso = dsos["[kernel]"];
+
+        FILE *file = fopen("/proc/kallsyms", "r");
+        if (!file) {
+                perror("failed to open kallsyms");
+                exit(-1);
+        }
+
+        char *line;
+        size_t n;
+
+        while (!feof(file)) {
+                uint64_t start;
+                char c;
+                char sym[1024];
+
+                if (getline(&line, &n, file) < 0)
+                        break;
+                if (!line)
+                        break;
+
+                if (sscanf(line, "%Lx %c %s", &start, &c, sym) == 3)
+                        dso.syms.insert(symbol(start, 0x1000000, std::string(sym)));
+        }
+        fclose(file);
+}
+
+struct map {
+        uint64_t start;
+        uint64_t end;
+        uint64_t pgoff;
+
+        std::string dso;
+
+        map() { };
+
+        map(uint64_t ip) : end(ip) { }
+
+        map(mmap_event *mmap) {
+                start = mmap->start;
+                end = mmap->start + mmap->len;
+                pgoff = mmap->pgoff;
+
+                dso = std::string(mmap->filename);
+
+                if (dsos.find(dso) == dsos.end())
+                        load_dso(dso);
+        };
+
+        bool operator < (const struct map &m) const {
+                return end < m.end;
+        };
+};
+
+typedef std::set<struct map> maps_t;
+
+static std::map<int, maps_t> maps;
+
+static std::map<int, std::string> comms;
+
+static std::map<std::string, int> hist;
+static std::multimap<int, std::string> rev_hist;
+
+static std::string resolve_comm(int pid)
+{
+        std::string comm = "<unknown>";
+        std::map<int, std::string>::const_iterator ci = comms.find(pid);
+        if (ci != comms.end())
+                comm = ci->second;
+
+        return comm;
+}
+
+static std::string resolve_user_symbol(int pid, uint64_t ip)
+{
+        std::string sym = "<unknown>";
+
+        maps_t &m = maps[pid];
+        maps_t::const_iterator mi = m.upper_bound(map(ip));
+        if (mi == m.end())
+                return sym;
+
+        ip -= mi->start + mi->pgoff;
+
+        symbols_t &s = dsos[mi->dso].syms;
+        symbols_t::const_iterator si = s.upper_bound(symbol(ip));
+
+        sym = mi->dso + ": <unknown>";
+
+        if (si == s.begin())
+                return sym;
+        si--;
+
+        if (si->start <= ip && ip < si->end)
+                sym = mi->dso + ": " + si->name;
+#if 0
+        else if (si->start <= ip)
+                sym = mi->dso + ": ?" + si->name;
+#endif
+
+        return sym;
+}
+
+static std::string resolve_kernel_symbol(uint64_t ip)
+{
+        std::string sym = "<unknown>";
+
+        symbols_t &s = dsos["[kernel]"].syms;
+        symbols_t::const_iterator si = s.upper_bound(symbol(ip));
+
+        if (si == s.begin())
+                return sym;
+        si--;
+
+        if (si->start <= ip && ip < si->end)
+                sym = si->name;
+
+        return sym;
+}
+
+static void display_help(void)
+{
+        printf(
+        "Usage: perf-report [<options>]\n"
+        " -i file   --input=<file>      # input file\n"
+        );
+
+        exit(0);
+}
+
+static void process_options(int argc, char *argv[])
+{
+        int error = 0;
+
+        for (;;) {
+                int option_index = 0;
+                /** Options for getopt */
+                static struct option long_options[] = {
+                        {"input",       required_argument,      NULL, 'i'},
+                        {NULL,          0,                      NULL,  0 }
+                };
+                int c = getopt_long(argc, argv, "+:i:",
+                                    long_options, &option_index);
+                if (c == -1)
+                        break;
+
+                switch (c) {
+                case 'i': input_name                    = strdup(optarg); break;
+                default: error = 1; break;
+                }
+        }
+
+        if (error)
+                display_help();
+}
+
+int main(int argc, char *argv[])
+{
+        unsigned long offset = 0;
+        unsigned long head = 0;
+        struct stat stat;
+        char *buf;
+        event_t *event;
+        int ret;
+        unsigned long total = 0;
+
+        page_size = getpagesize();
+
+        process_options(argc, argv);
+
+        input = open(input_name, O_RDONLY);
+        if (input < 0) {
+                perror("failed to open file");
+                exit(-1);
+        }
+
+        ret = fstat(input, &stat);
+        if (ret < 0) {
+                perror("failed to stat file");
+                exit(-1);
+        }
+
+        load_kallsyms();
+
+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);
+
+        if (head + event->header.size >= page_size * mmap_window) {
+                unsigned long shift = page_size * (head / page_size);
+
+                munmap(buf, page_size * mmap_window);
+                offset += shift;
+                head -= shift;
+                goto remap;
+        }
+        head += event->header.size;
+
+        if (event->header.misc & PERF_EVENT_MISC_OVERFLOW) {
+                std::string comm, sym, level;
+                char output[1024];
+
+                if (event->header.misc & PERF_EVENT_MISC_KERNEL) {
+                        level = "[kernel]";
+                        sym = resolve_kernel_symbol(event->ip.ip);
+                } else if (event->header.misc & PERF_EVENT_MISC_USER) {
+                        level = "[ user ]";
+                        sym = resolve_user_symbol(event->ip.pid, event->ip.ip);
+                } else {
+                        level = "[  hv  ]";
+                }
+                comm = resolve_comm(event->ip.pid);
+
+                snprintf(output, sizeof(output), "%16s %s %s",
+                                comm.c_str(), level.c_str(), sym.c_str());
+                hist[output]++;
+
+                total++;
+
+        } else switch (event->header.type) {
+        case PERF_EVENT_MMAP:
+                maps[event->mmap.pid].insert(map(&event->mmap));
+                break;
+
+        case PERF_EVENT_COMM:
+                comms[event->comm.pid] = std::string(event->comm.comm);
+                break;
+        }
+
+        if (offset + head < stat.st_size)
+                goto more;
+
+        close(input);
+
+        std::map<std::string, int>::iterator hi = hist.begin();
+
+        while (hi != hist.end()) {
+                rev_hist.insert(std::pair<int, std::string>(hi->second, hi->first));
+                hist.erase(hi++);
+        }
+
+        std::multimap<int, std::string>::const_iterator ri = rev_hist.begin();
+
+        while (ri != rev_hist.end()) {
+                printf(" %5.2f %s\n", (100.0 * ri->first)/total, ri->second.c_str());
+                ri++;
+        }
+
+        return 0;
+}
+