powertop/common/cpufreq.c

/*
 * Copyright 2009, Intel Corporation
 * Copyright 2009, Sun Microsystems, Inc
 *
 * This file is part of PowerTOP
 *
 * This program file is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program in a file named COPYING; if not, write to the
 * Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA
 *
 * Authors:
 *  Arjan van de Ven <arjan@linux.intel.com>
 *  Eric C Saxe <eric.saxe@sun.com>
 *  Aubrey Li <aubrey.li@intel.com>
 */

/*
 * GPL Disclaimer
 *
 * For the avoidance of doubt, except that if any license choice other
 * than GPL or LGPL is available it will apply instead, Sun elects to
 * use only the General Public License version 2 (GPLv2) at this time
 * for any software where a choice of GPL license versions is made
 * available with the language indicating that GPLv2 or any later
 * version may be used, or where a choice of which version of the GPL
 * is applied is otherwise unspecified.
 */

#include <stdlib.h>
#include <string.h>
#include <dtrace.h>
#include <kstat.h>
#include <errno.h>
#include "powertop.h"

#define HZ2MHZ(speed)   ((speed) / MICROSEC)
#define DTP_ARG_COUNT   2
#define DTP_ARG_LENGTH  5

static uint64_t     max_cpufreq = 0;
static dtrace_hdl_t *dtp;
static char     **dtp_argv;

/*
 * Enabling PM through /etc/power.conf
 * See pt_cpufreq_suggest()
 */
static char default_conf[]  = "/etc/power.conf";
static char default_pmconf[]    = "/usr/sbin/pmconfig";
static char cpupm_enable[]  = "echo cpupm enable >> /etc/power.conf";
static char cpupm_treshold[]    = "echo cpu-threshold 1s >> /etc/power.conf";

/*
 * Buffer containing DTrace program to track CPU frequency transitions
 */
static const char *dtp_cpufreq =
"hrtime_t last[$0];"
""
"BEGIN"
"{"
"   begin = timestamp;"
"}"
""
":::cpu-change-speed"
"/last[(processorid_t)arg0] != 0/"
"{"
"   this->cpu = (processorid_t)arg0;"
"   this->oldspeed = (uint64_t)arg1;"
"   @times[this->cpu, this->oldspeed] = sum(timestamp - last[this->cpu]);"
"   last[this->cpu] = timestamp;"
"}"
":::cpu-change-speed"
"/last[(processorid_t)arg0] == 0/"
"{"
"   this->cpu = (processorid_t)arg0;"
"   this->oldspeed = (uint64_t)arg1;"
"   @times[this->cpu, this->oldspeed] = sum(timestamp - begin);"
"   last[this->cpu] = timestamp;"
"}";

/*
 * Same as above, but only for a specific CPU
 */
static const char *dtp_cpufreq_c =
"hrtime_t last;"
""
"BEGIN"
"{"
"   begin = timestamp;"
"}"
""
":::cpu-change-speed"
"/(processorid_t)arg0 == $1 &&"
" last != 0/"
"{"
"   this->cpu = (processorid_t)arg0;"
"   this->oldspeed = (uint64_t)arg1;"
"   @times[this->cpu, this->oldspeed] = sum(timestamp - last);"
"   last = timestamp;"
"}"
":::cpu-change-speed"
"/(processorid_t)arg0 == $1 &&"
" last == 0/"
"{"
"   this->cpu = (processorid_t)arg0;"
"   this->oldspeed = (uint64_t)arg1;"
"   @times[this->cpu, this->oldspeed] = sum(timestamp - begin);"
"   last = timestamp;"
"}";

static int  pt_cpufreq_setup(void);
static int  pt_cpufreq_snapshot(void);
static int  pt_cpufreq_dtrace_walk(const dtrace_aggdata_t *, void *);
static void pt_cpufreq_stat_account(double, uint_t);
static int  pt_cpufreq_snapshot_cpu(kstat_ctl_t *, uint_t);
static int  pt_cpufreq_check_pm(void);
static void pt_cpufreq_enable(void);

static int
pt_cpufreq_setup(void)
{
    if ((dtp_argv = malloc(sizeof (char *) * DTP_ARG_COUNT)) == NULL)
        return (1);

    if ((dtp_argv[0] = malloc(sizeof (char) * DTP_ARG_LENGTH)) == NULL) {
        free(dtp_argv);
        return (1);
    }

    (void) snprintf(dtp_argv[0], 5, "%d\0", g_ncpus_observed);

    if (PT_ON_CPU) {
        if ((dtp_argv[1] = malloc(sizeof (char) * DTP_ARG_LENGTH))
            == NULL) {
            free(dtp_argv[0]);
            free(dtp_argv);
            return (1);
        }
        (void) snprintf(dtp_argv[1], 5, "%d\0", g_observed_cpu);
    }

    return (0);
}

/*
 * Perform setup necessary to enumerate and track CPU speed changes
 */
int
pt_cpufreq_stat_prepare(void)
{
    dtrace_prog_t       *prog;
    dtrace_proginfo_t   info;
    dtrace_optval_t     statustime;
    kstat_ctl_t         *kc;
    kstat_t         *ksp;
    kstat_named_t       *knp;
    freq_state_info_t   *state;
    char            *s, *token, *prog_ptr;
    int             err;

    if ((err = pt_cpufreq_setup()) != 0) {
        pt_error("failed to setup %s report (couldn't allocate "
            "memory)\n", g_msg_freq_state);
        return (errno);
    }

    state = g_pstate_info;
    if ((g_cpu_power_states = calloc((size_t)g_ncpus,
        sizeof (cpu_power_info_t))) == NULL)
        return (-1);

    /*
     * Enumerate the CPU frequencies
     */
    if ((kc = kstat_open()) == NULL)
        return (errno);

    ksp = kstat_lookup(kc, "cpu_info", g_cpu_table[g_observed_cpu], NULL);

    if (ksp == NULL) {
        err = errno;
        (void) kstat_close(kc);
        return (err);
    }

    (void) kstat_read(kc, ksp, NULL);

    knp = kstat_data_lookup(ksp, "supported_frequencies_Hz");
    s = knp->value.str.addr.ptr;

    g_npstates = 0;

    for (token = strtok(s, ":"), s = NULL;
        token != NULL && g_npstates < NSTATES;
        token = strtok(NULL, ":")) {

        state->speed = HZ2MHZ(atoll(token));

        if (state->speed > max_cpufreq)
            max_cpufreq = state->speed;

        state->total_time = (uint64_t)0;

        g_npstates++;
        state++;
    }

    if (token != NULL)
        pt_error("CPU exceeds the supported number of %s\n",
            g_msg_freq_state);

    (void) kstat_close(kc);

    /*
     * Return if speed transition is not supported
     */
    if (g_npstates < 2)
        return (-1);

    /*
     * Setup DTrace to look for CPU frequency changes
     */
    if ((dtp = dtrace_open(DTRACE_VERSION, 0, &err)) == NULL) {
        pt_error("cannot open dtrace library for the %s report: %s\n",
            g_msg_freq_state, dtrace_errmsg(NULL, err));
        return (-2);
    }

    /*
     * Execute different scripts (defined above) depending on
     * user specified options. Default mode uses dtp_cpufreq.
     */
    if (PT_ON_CPU)
        prog_ptr = (char *)dtp_cpufreq_c;
    else
        prog_ptr = (char *)dtp_cpufreq;

    if ((prog = dtrace_program_strcompile(dtp, prog_ptr,
        DTRACE_PROBESPEC_NAME, 0, (1 + g_argc), dtp_argv)) == NULL) {
        pt_error("failed to compile %s program\n", g_msg_freq_state);
        return (dtrace_errno(dtp));
    }

    if (dtrace_program_exec(dtp, prog, &info) == -1) {
        pt_error("failed to enable %s probes\n", g_msg_freq_state);
        return (dtrace_errno(dtp));
    }

    if (dtrace_setopt(dtp, "aggsize", "128k") == -1)
        pt_error("failed to set %s 'aggsize'\n", g_msg_freq_state);

    if (dtrace_setopt(dtp, "aggrate", "0") == -1)
        pt_error("failed to set %s 'aggrate'\n", g_msg_freq_state);

    if (dtrace_setopt(dtp, "aggpercpu", 0) == -1)
        pt_error("failed to set %s 'aggpercpu'\n", g_msg_freq_state);

    if (dtrace_go(dtp) != 0) {
        pt_error("failed to start %s observation\n", g_msg_freq_state);
        return (dtrace_errno(dtp));
    }

    if (dtrace_getopt(dtp, "statusrate", &statustime) == -1) {
        pt_error("failed to get %s 'statusrate'\n", g_msg_freq_state);
        return (dtrace_errno(dtp));
    }

    return (0);
}

/*
 * The DTrace probes have already been enabled, and are tracking
 * CPU speed transitions. Take a snapshot of the aggregations, and
 * look for any CPUs that have made a speed transition over the last
 * sampling interval. Note that the aggregations may be empty if no
 * speed transitions took place over the last interval. In that case,
 * notate that we have already accounted for the time, so that when
 * we do encounter a speed transition in a future sampling interval
 * we can subtract that time back out.
 */
int
pt_cpufreq_stat_collect(double interval)
{
    int i, ret;

    /*
     * Zero out the interval time reported by DTrace for
     * this interval
     */
    for (i = 0; i < g_npstates; i++)
        g_pstate_info[i].total_time = 0;

    for (i = 0; i < g_ncpus; i++)
        g_cpu_power_states[i].dtrace_time = 0;

    if (dtrace_status(dtp) == -1)
        return (-1);

    if (dtrace_aggregate_snap(dtp) != 0)
        pt_error("failed to collect data for %s\n", g_msg_freq_state);

    if (dtrace_aggregate_walk_keyvarsorted(dtp, pt_cpufreq_dtrace_walk,
        NULL) != 0)
        pt_error("failed to sort data for %s\n", g_msg_freq_state);

    dtrace_aggregate_clear(dtp);

    if ((ret = pt_cpufreq_snapshot()) != 0) {
        pt_error("failed to snapshot %s state\n", g_msg_freq_state);
        return (ret);
    }

    switch (g_op_mode) {
    case PT_MODE_CPU:
        pt_cpufreq_stat_account(interval, g_observed_cpu);
        break;
    case PT_MODE_DEFAULT:
    default:
        for (i = 0; i < g_ncpus_observed; i++)
            pt_cpufreq_stat_account(interval, i);
        break;
    }

    return (0);
}

static void
pt_cpufreq_stat_account(double interval, uint_t cpu)
{
    cpu_power_info_t    *cpu_pow;
    uint64_t        speed;
    hrtime_t        duration;
    int         i;

    cpu_pow = &g_cpu_power_states[cpu];
    speed = cpu_pow->current_pstate;

    duration = (hrtime_t)(interval * NANOSEC) - cpu_pow->dtrace_time;

    /*
     * 'duration' may be a negative value when we're using or forcing a
     * small interval, and the amount of time already accounted ends up
     * being larger than the the former.
     */
    if (duration < 0)
        return;

    for (i = 0; i < g_npstates; i++) {
        if (g_pstate_info[i].speed == speed) {
            g_pstate_info[i].total_time += duration;
            cpu_pow->time_accounted += duration;
            cpu_pow->speed_accounted = speed;
        }
    }
}

/*
 * Take a snapshot of each CPU's speed by looking through the cpu_info kstats.
 */
static int
pt_cpufreq_snapshot(void)
{
    kstat_ctl_t     *kc;
    int         ret;
    uint_t      i;

    if ((kc = kstat_open()) == NULL)
        return (errno);

    switch (g_op_mode) {
    case PT_MODE_CPU:
        ret = pt_cpufreq_snapshot_cpu(kc, g_observed_cpu);
        break;
    case PT_MODE_DEFAULT:
    default:
        for (i = 0; i < g_ncpus_observed; i++)
            if ((ret = pt_cpufreq_snapshot_cpu(kc, i)) != 0)
                break;
        break;
    }

    if (kstat_close(kc) != 0)
        pt_error("couldn't close %s kstat\n", g_msg_freq_state);

    return (ret);
}

static int
pt_cpufreq_snapshot_cpu(kstat_ctl_t *kc, uint_t cpu)
{
    kstat_t         *ksp;
    kstat_named_t       *knp;

    ksp = kstat_lookup(kc, "cpu_info", g_cpu_table[cpu], NULL);
    if (ksp == NULL) {
        pt_error("couldn't find 'cpu_info' kstat for CPU %d\n while "
            "taking a snapshot of %s\n", cpu, g_msg_freq_state);
        return (1);
    }

    if (kstat_read(kc, ksp, NULL) == -1) {
        pt_error("couldn't read 'cpu_info' kstat for CPU %d\n while "
            "taking a snapshot of %s\n", cpu, g_msg_freq_state);
        return (2);
    }

    knp = kstat_data_lookup(ksp, "current_clock_Hz");
    if (knp == NULL) {
        pt_error("couldn't find 'current_clock_Hz' kstat for CPU %d "
            "while taking a snapshot of %s\n", cpu, g_msg_freq_state);
        return (3);
    }

    g_cpu_power_states[cpu].current_pstate = HZ2MHZ(knp->value.ui64);

    return (0);
}

/*
 * DTrace aggregation walker that sorts through a snapshot of the
 * aggregation data collected during firings of the cpu-change-speed
 * probe.
 */
/*ARGSUSED*/
static int
pt_cpufreq_dtrace_walk(const dtrace_aggdata_t *data, void *arg)
{
    dtrace_aggdesc_t    *aggdesc = data->dtada_desc;
    dtrace_recdesc_t    *cpu_rec, *speed_rec;
    cpu_power_info_t    *cp;
    int32_t         cpu;
    uint64_t        speed;
    hrtime_t        res;
    int             i;

    if (strcmp(aggdesc->dtagd_name, "times") == 0) {
        cpu_rec = &aggdesc->dtagd_rec[1];
        speed_rec = &aggdesc->dtagd_rec[2];

        /* LINTED - alignment */
        cpu = *(int32_t *)(data->dtada_data + cpu_rec->dtrd_offset);

        /* LINTED - alignment */
        res = *((hrtime_t *)(data->dtada_percpu[cpu]));

        /* LINTED - alignment */
        speed = *(uint64_t *)(data->dtada_data +
            speed_rec->dtrd_offset);

        if (speed == 0)
            speed = max_cpufreq;
        else
            speed = HZ2MHZ(speed);

        /*
         * We have an aggregation record for "cpu" being at "speed"
         * for an interval of "n" nanoseconds. The reported interval
         * may exceed the powertop sampling interval, since we only
         * notice during potentially infrequent firings of the
         * "speed change" DTrace probe. In this case powertop would
         * have already accounted for the portions of the interval
         * that happened during prior powertop samplings, so subtract
         * out time already accounted.
         */
        cp = &g_cpu_power_states[cpu];

        for (i = 0; i < g_npstates; i++) {
            if (g_pstate_info[i].speed == speed) {

                if (cp->time_accounted > 0 &&
                    cp->speed_accounted == speed) {
                    if (res > cp->time_accounted) {
                        res -= cp->time_accounted;
                        cp->time_accounted = 0;
                        cp->speed_accounted = 0;
                    } else {
                        return (DTRACE_AGGWALK_NEXT);
                    }
                }

                g_pstate_info[i].total_time += res;
                cp->dtrace_time += res;
            }
        }
    }

    return (DTRACE_AGGWALK_NEXT);
}

/*
 * Checks if PM is enabled in /etc/power.conf, enabling if not
 */
void
pt_cpufreq_suggest(void)
{
    int ret = pt_cpufreq_check_pm();

    switch (ret) {
    case 0:
        pt_sugg_add("Suggestion: enable CPU power management by "
            "pressing the P key", 40, 'P', (char *)g_msg_freq_enable,
            pt_cpufreq_enable);
        break;
    }
}

/*
 * Checks /etc/power.conf and returns:
 *
 *     0 if CPUPM is not enabled
 *     1 if there's nothing for us to do because:
 *         (a) the system does not support frequency scaling
 *         (b) there's no power.conf.
 *     2 if CPUPM is enabled
 *     3 if the system is running in poll-mode, as opposed to event-mode
 *
 * Notice the ordering of the return values, they will be picked up and
 * switched upon ascendingly.
 */
static int
pt_cpufreq_check_pm(void)
{
    char line[1024];
    FILE *file;
    int ret = 0;

    if (g_npstates < 2 || (file = fopen(default_conf, "r")) == NULL)
        return (1);

    (void) memset(line, 0, 1024);

    while (fgets(line, 1024, file)) {
        if (strstr(line, "cpupm")) {
            if (strstr(line, "enable")) {
                (void) fclose(file);
                return (2);
            }
        }
        if (strstr(line, "poll"))
            ret = 3;
    }

    (void) fclose(file);

    return (ret);
}

/*
 * Used as a suggestion, sets PM in /etc/power.conf and
 * a 1sec threshold, then calls /usr/sbin/pmconfig
 */
static void
pt_cpufreq_enable(void)
{
    (void) system(cpupm_enable);
    (void) system(cpupm_treshold);
    (void) system(default_pmconf);

    if (pt_sugg_remove(pt_cpufreq_enable) == 0)
        pt_error("failed to remove a %s suggestion\n",
            g_msg_freq_state);
}