1 files changed, 264 insertions, 74 deletions

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 5b1b807265a1..a02c02f25e88 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -38,6 +38,8 @@
 #include <ctype.h>
 #include <sched.h>
 #include <cpuid.h>
+#include <linux/capability.h>
+#include <errno.h>
 
 char *proc_stat = "/proc/stat";
 unsigned int interval_sec = 5;  /* set with -i interval_sec */
@@ -59,8 +61,8 @@ unsigned int has_epb;
 unsigned int units = 1000000;   /* MHz etc */
 unsigned int genuine_intel;
 unsigned int has_invariant_tsc;
-unsigned int do_nehalem_platform_info;
-unsigned int do_nehalem_turbo_ratio_limit;
+unsigned int do_nhm_platform_info;
+unsigned int do_nhm_turbo_ratio_limit;
 unsigned int do_ivt_turbo_ratio_limit;
 unsigned int extra_msr_offset32;
 unsigned int extra_msr_offset64;
@@ -81,6 +83,9 @@ unsigned int tcc_activation_temp;
 unsigned int tcc_activation_temp_override;
 double rapl_power_units, rapl_energy_units, rapl_time_units;
 double rapl_joule_counter_range;
+unsigned int do_core_perf_limit_reasons;
+unsigned int do_gfx_perf_limit_reasons;
+unsigned int do_ring_perf_limit_reasons;
 
 #define RAPL_PKG                (1 << 0)
                                         /* 0x610 MSR_PKG_POWER_LIMIT */
@@ -251,15 +256,13 @@ int get_msr(int cpu, off_t offset, unsigned long long *msr)
         sprintf(pathname, "/dev/cpu/%d/msr", cpu);
         fd = open(pathname, O_RDONLY);
         if (fd < 0)
-                return -1;
+                err(-1, "%s open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root", pathname);
 
         retval = pread(fd, msr, sizeof *msr, offset);
         close(fd);
 
-        if (retval != sizeof *msr) {
-                fprintf(stderr, "%s offset 0x%llx read failed\n", pathname, (unsigned long long)offset);
-                return -1;
-        }
+        if (retval != sizeof *msr)
+                err(-1, "%s offset 0x%llx read failed", pathname, (unsigned long long)offset);
 
         return 0;
 }
@@ -281,7 +284,7 @@ void print_header(void)
                 outp += sprintf(outp, "     CPU");
         if (has_aperf)
                 outp += sprintf(outp, " Avg_MHz");
-        if (do_nhm_cstates)
+        if (has_aperf)
                 outp += sprintf(outp, "   %%Busy");
         if (has_aperf)
                 outp += sprintf(outp, " Bzy_MHz");
@@ -337,7 +340,7 @@ void print_header(void)
                         outp += sprintf(outp, "   PKG_%%");
                 if (do_rapl & RAPL_DRAM_PERF_STATUS)
                         outp += sprintf(outp, "   RAM_%%");
-        } else {
+        } else if (do_rapl && rapl_joules) {
                 if (do_rapl & RAPL_PKG)
                         outp += sprintf(outp, "   Pkg_J");
                 if (do_rapl & RAPL_CORES)
@@ -457,25 +460,25 @@ int format_counters(struct thread_data *t, struct core_data *c,
                         outp += sprintf(outp, "%8d", t->cpu_id);
         }
 
-        /* AvgMHz */
+        /* Avg_MHz */
         if (has_aperf)
                 outp += sprintf(outp, "%8.0f",
                         1.0 / units * t->aperf / interval_float);
 
-        /* %c0 */
-        if (do_nhm_cstates) {
+        /* %Busy */
+        if (has_aperf) {
                 if (!skip_c0)
                         outp += sprintf(outp, "%8.2f", 100.0 * t->mperf/t->tsc);
                 else
                         outp += sprintf(outp, "********");
         }
 
-        /* BzyMHz */
+        /* Bzy_MHz */
         if (has_aperf)
                 outp += sprintf(outp, "%8.0f",
                         1.0 * t->tsc / units * t->aperf / t->mperf / interval_float);
 
-        /* TSC */
+        /* TSC_MHz */
         outp += sprintf(outp, "%8.0f", 1.0 * t->tsc/units/interval_float);
 
         /* SMI */
@@ -561,7 +564,7 @@ int format_counters(struct thread_data *t, struct core_data *c,
                         outp += sprintf(outp, fmt8, 100.0 * p->rapl_pkg_perf_status * rapl_time_units / interval_float);
                 if (do_rapl & RAPL_DRAM_PERF_STATUS)
                         outp += sprintf(outp, fmt8, 100.0 * p->rapl_dram_perf_status * rapl_time_units / interval_float);
-        } else {
+        } else if (do_rapl && rapl_joules) {
                 if (do_rapl & RAPL_PKG)
                         outp += sprintf(outp, fmt8,
                                         p->energy_pkg * rapl_energy_units);
@@ -578,8 +581,8 @@ int format_counters(struct thread_data *t, struct core_data *c,
                         outp += sprintf(outp, fmt8, 100.0 * p->rapl_pkg_perf_status * rapl_time_units / interval_float);
                 if (do_rapl & RAPL_DRAM_PERF_STATUS)
                         outp += sprintf(outp, fmt8, 100.0 * p->rapl_dram_perf_status * rapl_time_units / interval_float);
-        outp += sprintf(outp, fmt8, interval_float);
 
+                outp += sprintf(outp, fmt8, interval_float);
         }
 done:
         outp += sprintf(outp, "\n");
@@ -670,24 +673,26 @@ delta_thread(struct thread_data *new, struct thread_data *old,
 
         old->c1 = new->c1 - old->c1;
 
-        if ((new->aperf > old->aperf) && (new->mperf > old->mperf)) {
-                old->aperf = new->aperf - old->aperf;
-                old->mperf = new->mperf - old->mperf;
-        } else {
+        if (has_aperf) {
+                if ((new->aperf > old->aperf) && (new->mperf > old->mperf)) {
+                        old->aperf = new->aperf - old->aperf;
+                        old->mperf = new->mperf - old->mperf;
+                } else {
 
-                if (!aperf_mperf_unstable) {
-                        fprintf(stderr, "%s: APERF or MPERF went backwards *\n", progname);
-                        fprintf(stderr, "* Frequency results do not cover entire interval *\n");
-                        fprintf(stderr, "* fix this by running Linux-2.6.30 or later *\n");
+                        if (!aperf_mperf_unstable) {
+                                fprintf(stderr, "%s: APERF or MPERF went backwards *\n", progname);
+                                fprintf(stderr, "* Frequency results do not cover entire interval *\n");
+                                fprintf(stderr, "* fix this by running Linux-2.6.30 or later *\n");
 
-                        aperf_mperf_unstable = 1;
+                                aperf_mperf_unstable = 1;
+                        }
+                        /*
+                         * mperf delta is likely a huge "positive" number
+                         * can not use it for calculating c0 time
+                         */
+                        skip_c0 = 1;
+                        skip_c1 = 1;
                 }
-                /*
-                 * mperf delta is likely a huge "positive" number
-                 * can not use it for calculating c0 time
-                 */
-                skip_c0 = 1;
-                skip_c1 = 1;
         }
 
 
@@ -1019,7 +1024,7 @@ void print_verbose_header(void)
         unsigned long long msr;
         unsigned int ratio;
 
-        if (!do_nehalem_platform_info)
+        if (!do_nhm_platform_info)
                 return;
 
         get_msr(0, MSR_NHM_PLATFORM_INFO, &msr);
@@ -1132,7 +1137,7 @@ print_nhm_turbo_ratio_limits:
         }
         fprintf(stderr, ")\n");
 
-        if (!do_nehalem_turbo_ratio_limit)
+        if (!do_nhm_turbo_ratio_limit)
                 return;
 
         get_msr(0, MSR_NHM_TURBO_RATIO_LIMIT, &msr);
@@ -1178,6 +1183,7 @@ print_nhm_turbo_ratio_limits:
         if (ratio)
                 fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 1 active cores\n",
                         ratio, bclk, ratio * bclk);
+
 }
 
 void free_all_buffers(void)
@@ -1458,17 +1464,60 @@ void check_dev_msr()
         struct stat sb;
 
         if (stat("/dev/cpu/0/msr", &sb))
-                err(-5, "no /dev/cpu/0/msr\n"
-                    "Try \"# modprobe msr\"");
+                err(-5, "no /dev/cpu/0/msr, Try \"# modprobe msr\" ");
 }
 
-void check_super_user()
+void check_permissions()
 {
-        if (getuid() != 0)
-                errx(-6, "must be root");
+        struct __user_cap_header_struct cap_header_data;
+        cap_user_header_t cap_header = &cap_header_data;
+        struct __user_cap_data_struct cap_data_data;
+        cap_user_data_t cap_data = &cap_data_data;
+        extern int capget(cap_user_header_t hdrp, cap_user_data_t datap);
+        int do_exit = 0;
+
+        /* check for CAP_SYS_RAWIO */
+        cap_header->pid = getpid();
+        cap_header->version = _LINUX_CAPABILITY_VERSION;
+        if (capget(cap_header, cap_data) < 0)
+                err(-6, "capget(2) failed");
+
+        if ((cap_data->effective & (1 << CAP_SYS_RAWIO)) == 0) {
+                do_exit++;
+                warnx("capget(CAP_SYS_RAWIO) failed,"
+                        " try \"# setcap cap_sys_rawio=ep %s\"", progname);
+        }
+
+        /* test file permissions */
+        if (euidaccess("/dev/cpu/0/msr", R_OK)) {
+                do_exit++;
+                warn("/dev/cpu/0/msr open failed, try chown or chmod +r /dev/cpu/*/msr");
+        }
+
+        /* if all else fails, thell them to be root */
+        if (do_exit)
+                if (getuid() != 0)
+                        warnx("... or simply run as root");
+
+        if (do_exit)
+                exit(-6);
 }
 
-int has_nehalem_turbo_ratio_limit(unsigned int family, unsigned int model)
+/*
+ * NHM adds support for additional MSRs:
+ *
+ * MSR_SMI_COUNT                   0x00000034
+ *
+ * MSR_NHM_PLATFORM_INFO           0x000000ce
+ * MSR_NHM_SNB_PKG_CST_CFG_CTL     0x000000e2
+ *
+ * MSR_PKG_C3_RESIDENCY            0x000003f8
+ * MSR_PKG_C6_RESIDENCY            0x000003f9
+ * MSR_CORE_C3_RESIDENCY           0x000003fc
+ * MSR_CORE_C6_RESIDENCY           0x000003fd
+ *
+ */
+int has_nhm_msrs(unsigned int family, unsigned int model)
 {
         if (!genuine_intel)
                 return 0;
@@ -1495,13 +1544,27 @@ int has_nehalem_turbo_ratio_limit(unsigned int family, unsigned int model)
         case 0x3D:      /* BDW */
         case 0x4F:      /* BDX */
         case 0x56:      /* BDX-DE */
-                return 1;
         case 0x2E:      /* Nehalem-EX Xeon - Beckton */
         case 0x2F:      /* Westmere-EX Xeon - Eagleton */
+                return 1;
         default:
                 return 0;
         }
 }
+int has_nhm_turbo_ratio_limit(unsigned int family, unsigned int model)
+{
+        if (!has_nhm_msrs(family, model))
+                return 0;
+
+        switch (model) {
+        /* Nehalem compatible, but do not include turbo-ratio limit support */
+        case 0x2E:      /* Nehalem-EX Xeon - Beckton */
+        case 0x2F:      /* Westmere-EX Xeon - Eagleton */
+                return 0;
+        default:
+                return 1;
+        }
+}
 int has_ivt_turbo_ratio_limit(unsigned int family, unsigned int model)
 {
         if (!genuine_intel)
@@ -1564,6 +1627,103 @@ int print_epb(struct thread_data *t, struct core_data *c, struct pkg_data *p)
         return 0;
 }
 
+/*
+ * print_perf_limit()
+ */
+int print_perf_limit(struct thread_data *t, struct core_data *c, struct pkg_data *p)
+{
+        unsigned long long msr;
+        int cpu;
+
+        cpu = t->cpu_id;
+
+        /* per-package */
+        if (!(t->flags & CPU_IS_FIRST_THREAD_IN_CORE) || !(t->flags & CPU_IS_FIRST_CORE_IN_PACKAGE))
+                return 0;
+
+        if (cpu_migrate(cpu)) {
+                fprintf(stderr, "Could not migrate to CPU %d\n", cpu);
+                return -1;
+        }
+
+        if (do_core_perf_limit_reasons) {
+                get_msr(cpu, MSR_CORE_PERF_LIMIT_REASONS, &msr);
+                fprintf(stderr, "cpu%d: MSR_CORE_PERF_LIMIT_REASONS, 0x%08llx", cpu, msr);
+                fprintf(stderr, " (Active: %s%s%s%s%s%s%s%s%s%s%s%s%s%s)",
+                        (msr & 1 << 0) ? "PROCHOT, " : "",
+                        (msr & 1 << 1) ? "ThermStatus, " : "",
+                        (msr & 1 << 2) ? "bit2, " : "",
+                        (msr & 1 << 4) ? "Graphics, " : "",
+                        (msr & 1 << 5) ? "Auto-HWP, " : "",
+                        (msr & 1 << 6) ? "VR-Therm, " : "",
+                        (msr & 1 << 8) ? "Amps, " : "",
+                        (msr & 1 << 9) ? "CorePwr, " : "",
+                        (msr & 1 << 10) ? "PkgPwrL1, " : "",
+                        (msr & 1 << 11) ? "PkgPwrL2, " : "",
+                        (msr & 1 << 12) ? "MultiCoreTurbo, " : "",
+                        (msr & 1 << 13) ? "Transitions, " : "",
+                        (msr & 1 << 14) ? "bit14, " : "",
+                        (msr & 1 << 15) ? "bit15, " : "");
+                fprintf(stderr, " (Logged: %s%s%s%s%s%s%s%s%s%s%s%s%s%s)\n",
+                        (msr & 1 << 16) ? "PROCHOT, " : "",
+                        (msr & 1 << 17) ? "ThermStatus, " : "",
+                        (msr & 1 << 18) ? "bit18, " : "",
+                        (msr & 1 << 20) ? "Graphics, " : "",
+                        (msr & 1 << 21) ? "Auto-HWP, " : "",
+                        (msr & 1 << 22) ? "VR-Therm, " : "",
+                        (msr & 1 << 24) ? "Amps, " : "",
+                        (msr & 1 << 25) ? "CorePwr, " : "",
+                        (msr & 1 << 26) ? "PkgPwrL1, " : "",
+                        (msr & 1 << 27) ? "PkgPwrL2, " : "",
+                        (msr & 1 << 28) ? "MultiCoreTurbo, " : "",
+                        (msr & 1 << 29) ? "Transitions, " : "",
+                        (msr & 1 << 30) ? "bit30, " : "",
+                        (msr & 1 << 31) ? "bit31, " : "");
+
+        }
+        if (do_gfx_perf_limit_reasons) {
+                get_msr(cpu, MSR_GFX_PERF_LIMIT_REASONS, &msr);
+                fprintf(stderr, "cpu%d: MSR_GFX_PERF_LIMIT_REASONS, 0x%08llx", cpu, msr);
+                fprintf(stderr, " (Active: %s%s%s%s%s%s%s%s)",
+                        (msr & 1 << 0) ? "PROCHOT, " : "",
+                        (msr & 1 << 1) ? "ThermStatus, " : "",
+                        (msr & 1 << 4) ? "Graphics, " : "",
+                        (msr & 1 << 6) ? "VR-Therm, " : "",
+                        (msr & 1 << 8) ? "Amps, " : "",
+                        (msr & 1 << 9) ? "GFXPwr, " : "",
+                        (msr & 1 << 10) ? "PkgPwrL1, " : "",
+                        (msr & 1 << 11) ? "PkgPwrL2, " : "");
+                fprintf(stderr, " (Logged: %s%s%s%s%s%s%s%s)\n",
+                        (msr & 1 << 16) ? "PROCHOT, " : "",
+                        (msr & 1 << 17) ? "ThermStatus, " : "",
+                        (msr & 1 << 20) ? "Graphics, " : "",
+                        (msr & 1 << 22) ? "VR-Therm, " : "",
+                        (msr & 1 << 24) ? "Amps, " : "",
+                        (msr & 1 << 25) ? "GFXPwr, " : "",
+                        (msr & 1 << 26) ? "PkgPwrL1, " : "",
+                        (msr & 1 << 27) ? "PkgPwrL2, " : "");
+        }
+        if (do_ring_perf_limit_reasons) {
+                get_msr(cpu, MSR_RING_PERF_LIMIT_REASONS, &msr);
+                fprintf(stderr, "cpu%d: MSR_RING_PERF_LIMIT_REASONS, 0x%08llx", cpu, msr);
+                fprintf(stderr, " (Active: %s%s%s%s%s%s)",
+                        (msr & 1 << 0) ? "PROCHOT, " : "",
+                        (msr & 1 << 1) ? "ThermStatus, " : "",
+                        (msr & 1 << 6) ? "VR-Therm, " : "",
+                        (msr & 1 << 8) ? "Amps, " : "",
+                        (msr & 1 << 10) ? "PkgPwrL1, " : "",
+                        (msr & 1 << 11) ? "PkgPwrL2, " : "");
+                fprintf(stderr, " (Logged: %s%s%s%s%s%s)\n",
+                        (msr & 1 << 16) ? "PROCHOT, " : "",
+                        (msr & 1 << 17) ? "ThermStatus, " : "",
+                        (msr & 1 << 22) ? "VR-Therm, " : "",
+                        (msr & 1 << 24) ? "Amps, " : "",
+                        (msr & 1 << 26) ? "PkgPwrL1, " : "",
+                        (msr & 1 << 27) ? "PkgPwrL2, " : "");
+        }
+        return 0;
+}
+
 #define RAPL_POWER_GRANULARITY  0x7FFF  /* 15 bit power granularity */
 #define RAPL_TIME_GRANULARITY   0x3F /* 6 bit time granularity */
 
@@ -1653,6 +1813,27 @@ void rapl_probe(unsigned int family, unsigned int model)
         return;
 }
 
+void perf_limit_reasons_probe(family, model)
+{
+        if (!genuine_intel)
+                return;
+
+        if (family != 6)
+                return;
+
+        switch (model) {
+        case 0x3C:      /* HSW */
+        case 0x45:      /* HSW */
+        case 0x46:      /* HSW */
+                do_gfx_perf_limit_reasons = 1;
+        case 0x3F:      /* HSX */
+                do_core_perf_limit_reasons = 1;
+                do_ring_perf_limit_reasons = 1;
+        default:
+                return;
+        }
+}
+
 int print_thermal(struct thread_data *t, struct core_data *c, struct pkg_data *p)
 {
         unsigned long long msr;
@@ -1842,8 +2023,15 @@ int print_rapl(struct thread_data *t, struct core_data *c, struct pkg_data *p)
         return 0;
 }
 
+/*
+ * SNB adds support for additional MSRs:
+ *
+ * MSR_PKG_C7_RESIDENCY            0x000003fa
+ * MSR_CORE_C7_RESIDENCY           0x000003fe
+ * MSR_PKG_C2_RESIDENCY            0x0000060d
+ */
 
-int is_snb(unsigned int family, unsigned int model)
+int has_snb_msrs(unsigned int family, unsigned int model)
 {
         if (!genuine_intel)
                 return 0;
@@ -1865,7 +2053,14 @@ int is_snb(unsigned int family, unsigned int model)
         return 0;
 }
 
-int has_c8_c9_c10(unsigned int family, unsigned int model)
+/*
+ * HSW adds support for additional MSRs:
+ *
+ * MSR_PKG_C8_RESIDENCY            0x00000630
+ * MSR_PKG_C9_RESIDENCY            0x00000631
+ * MSR_PKG_C10_RESIDENCY           0x00000632
+ */
+int has_hsw_msrs(unsigned int family, unsigned int model)
 {
         if (!genuine_intel)
                 return 0;
@@ -1917,7 +2112,7 @@ double slm_bclk(void)
 
 double discover_bclk(unsigned int family, unsigned int model)
 {
-        if (is_snb(family, model))
+        if (has_snb_msrs(family, model))
                 return 100.00;
         else if (is_slm(family, model))
                 return slm_bclk();
@@ -1965,7 +2160,7 @@ int set_temperature_target(struct thread_data *t, struct core_data *c, struct pk
         }
 
         /* Temperature Target MSR is Nehalem and newer only */
-        if (!do_nehalem_platform_info)
+        if (!do_nhm_platform_info)
                 goto guess;
 
         if (get_msr(0, MSR_IA32_TEMPERATURE_TARGET, &msr))
@@ -2029,18 +2224,15 @@ void check_cpuid()
         ebx = ecx = edx = 0;
         __get_cpuid(0x80000000, &max_level, &ebx, &ecx, &edx);
 
-        if (max_level < 0x80000007)
-                errx(1, "CPUID: no invariant TSC (max_level 0x%x)", max_level);
+        if (max_level >= 0x80000007) {
 
-        /*
-         * Non-Stop TSC is advertised by CPUID.EAX=0x80000007: EDX.bit8
-         * this check is valid for both Intel and AMD
-         */
-        __get_cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
-        has_invariant_tsc = edx & (1 << 8);
-
-        if (!has_invariant_tsc)
-                errx(1, "No invariant TSC");
+                /*
+                 * Non-Stop TSC is advertised by CPUID.EAX=0x80000007: EDX.bit8
+                 * this check is valid for both Intel and AMD
+                 */
+                __get_cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
+                has_invariant_tsc = edx & (1 << 8);
+        }
 
         /*
          * APERF/MPERF is advertised by CPUID.EAX=0x6: ECX.bit0
@@ -2054,26 +2246,22 @@ void check_cpuid()
         has_epb = ecx & (1 << 3);
 
         if (verbose)
-                fprintf(stderr, "CPUID(6): %s%s%s%s\n",
-                        has_aperf ? "APERF" : "No APERF!",
-                        do_dts ? ", DTS" : "",
-                        do_ptm ? ", PTM": "",
-                        has_epb ? ", EPB": "");
-
-        if (!has_aperf)
-                errx(-1, "No APERF");
-
-        do_nehalem_platform_info = genuine_intel && has_invariant_tsc;
-        do_nhm_cstates = genuine_intel; /* all Intel w/ non-stop TSC have NHM counters */
-        do_smi = do_nhm_cstates;
-        do_snb_cstates = is_snb(family, model);
-        do_c8_c9_c10 = has_c8_c9_c10(family, model);
+                fprintf(stderr, "CPUID(6): %sAPERF, %sDTS, %sPTM, %sEPB\n",
+                        has_aperf ? "" : "No ",
+                        do_dts ? "" : "No ",
+                        do_ptm ? "" : "No ",
+                        has_epb ? "" : "No ");
+
+        do_nhm_platform_info = do_nhm_cstates = do_smi = has_nhm_msrs(family, model);
+        do_snb_cstates = has_snb_msrs(family, model);
+        do_c8_c9_c10 = has_hsw_msrs(family, model);
         do_slm_cstates = is_slm(family, model);
         bclk = discover_bclk(family, model);
 
-        do_nehalem_turbo_ratio_limit = has_nehalem_turbo_ratio_limit(family, model);
+        do_nhm_turbo_ratio_limit = has_nhm_turbo_ratio_limit(family, model);
         do_ivt_turbo_ratio_limit = has_ivt_turbo_ratio_limit(family, model);
         rapl_probe(family, model);
+        perf_limit_reasons_probe(family, model);
 
         return;
 }
@@ -2299,10 +2487,9 @@ void setup_all_buffers(void)
 
 void turbostat_init()
 {
-        check_cpuid();
-
         check_dev_msr();
-        check_super_user();
+        check_permissions();
+        check_cpuid();
 
         setup_all_buffers();
 
@@ -2313,6 +2500,9 @@ void turbostat_init()
                 for_all_cpus(print_epb, ODD_COUNTERS);
 
         if (verbose)
+                for_all_cpus(print_perf_limit, ODD_COUNTERS);
+
+        if (verbose)
                 for_all_cpus(print_rapl, ODD_COUNTERS);
 
         for_all_cpus(set_temperature_target, ODD_COUNTERS);
@@ -2441,7 +2631,7 @@ int main(int argc, char **argv)
         cmdline(argc, argv);
 
         if (verbose)
-                fprintf(stderr, "turbostat v3.7 Feb 6, 2014"
+                fprintf(stderr, "turbostat v3.9 23-Jan, 2015"
                         " - Len Brown <lenb@kernel.org>\n");
 
         turbostat_init();