tools: create power/x86/turbostat

turbostat is a Linux tool to observe proper operation
of Intel(R) Turbo Boost Technology.

turbostat displays the actual processor frequency
on x86 processors that include APERF and MPERF MSRs.

Note that turbostat is of limited utility on Linux
kernels 2.6.29 and older, as acpi_cpufreq cleared
APERF/MPERF up through that release.

On Intel Core i3/i5/i7 (Nehalem) and newer processors,
turbostat also displays residency in idle power saving states,
which are necessary for diagnosing any cpuidle issues
that may have an effect on turbo-mode.

See the turbostat.8 man page for example usage.

Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 1228 insertions, 0 deletions

diff --git a/tools/power/x86/turbostat/Makefile b/tools/power/x86/turbostat/Makefile
new file mode 100644
index 00000000000..fd8e1f1297a
--- /dev/null
+++ b/tools/power/x86/turbostat/Makefile
@@ -0,0 +1,8 @@
+turbostat : turbostat.c
+
+clean :
+	rm -f turbostat
+
+install :
+	install turbostat /usr/bin/turbostat
+	install turbostat.8 /usr/share/man/man8
diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8
new file mode 100644
index 00000000000..ff75125deed
--- /dev/null
+++ b/tools/power/x86/turbostat/turbostat.8
@@ -0,0 +1,172 @@
+.TH TURBOSTAT 8
+.SH NAME
+turbostat \- Report processor frequency and idle statistics
+.SH SYNOPSIS
+.ft B
+.B turbostat
+.RB [ "\-v" ]
+.RB [ "\-M MSR#" ]
+.RB command
+.br
+.B turbostat
+.RB [ "\-v" ]
+.RB [ "\-M MSR#" ]
+.RB [ "\-i interval_sec" ]
+.SH DESCRIPTION
+\fBturbostat \fP reports processor topology, frequency
+and idle power state statistics on modern X86 processors.
+Either \fBcommand\fP is forked and statistics are printed
+upon its completion, or statistics are printed periodically.
+
+\fBturbostat \fP
+requires that the processor
+supports an "invariant" TSC, plus the APERF and MPERF MSRs.
+\fBturbostat \fP will report idle cpu power state residency
+on processors that additionally support C-state residency counters.
+
+.SS Options
+The \fB-v\fP option increases verbosity.
+.PP
+The \fB-M MSR#\fP option dumps the specified MSR,
+in addition to the usual frequency and idle statistics.
+.PP
+The \fB-i interval_sec\fP option prints statistics every \fiinterval_sec\fP seconds.
+The default is 5 seconds.
+.PP
+The \fBcommand\fP parameter forks \fBcommand\fP and upon its exit,
+displays the statistics gathered since it was forked.
+.PP
+.SH FIELD DESCRIPTIONS
+.nf
+\fBpkg\fP processor package number.
+\fBcore\fP processor core number.
+\fBCPU\fP Linux CPU (logical processor) number.
+\fB%c0\fP percent of the interval that the CPU retired instructions.
+\fBGHz\fP average clock rate while the CPU was in c0 state.
+\fBTSC\fP average GHz that the TSC ran during the entire interval.
+\fB%c1, %c3, %c6\fP show the percentage residency in hardware core idle states.
+\fB%pc3, %pc6\fP percentage residency in hardware package idle states.
+.fi
+.PP
+.SH EXAMPLE
+Without any parameters, turbostat prints out counters ever 5 seconds.
+(override interval with "-i sec" option, or specify a command
+for turbostat to fork).
+
+The first row of statistics reflect the average for the entire system.
+Subsequent rows show per-CPU statistics.
+
+.nf
+[root@x980]# ./turbostat
+core CPU   %c0   GHz  TSC   %c1    %c3    %c6   %pc3   %pc6
+          0.04 1.62 3.38   0.11   0.00  99.85   0.00  95.07
+  0   0   0.04 1.62 3.38   0.06   0.00  99.90   0.00  95.07
+  0   6   0.02 1.62 3.38   0.08   0.00  99.90   0.00  95.07
+  1   2   0.10 1.62 3.38   0.29   0.00  99.61   0.00  95.07
+  1   8   0.11 1.62 3.38   0.28   0.00  99.61   0.00  95.07
+  2   4   0.01 1.62 3.38   0.01   0.00  99.98   0.00  95.07
+  2  10   0.01 1.61 3.38   0.02   0.00  99.98   0.00  95.07
+  8   1   0.07 1.62 3.38   0.15   0.00  99.78   0.00  95.07
+  8   7   0.03 1.62 3.38   0.19   0.00  99.78   0.00  95.07
+  9   3   0.01 1.62 3.38   0.02   0.00  99.98   0.00  95.07
+  9   9   0.01 1.62 3.38   0.02   0.00  99.98   0.00  95.07
+ 10   5   0.01 1.62 3.38   0.13   0.00  99.86   0.00  95.07
+ 10  11   0.08 1.62 3.38   0.05   0.00  99.86   0.00  95.07
+.fi
+.SH VERBOSE EXAMPLE
+The "-v" option adds verbosity to the output:
+
+.nf
+GenuineIntel 11 CPUID levels; family:model:stepping 0x6:2c:2 (6:44:2)
+12 * 133 = 1600 MHz max efficiency
+25 * 133 = 3333 MHz TSC frequency
+26 * 133 = 3467 MHz max turbo 4 active cores
+26 * 133 = 3467 MHz max turbo 3 active cores
+27 * 133 = 3600 MHz max turbo 2 active cores
+27 * 133 = 3600 MHz max turbo 1 active cores
+
+.fi
+The \fBmax efficiency\fP frequency, a.k.a. Low Frequency Mode, is the frequency
+available at the minimum package voltage.  The \fBTSC frequency\fP is the nominal
+maximum frequency of the processor if turbo-mode were not available.  This frequency
+should be sustainable on all CPUs indefinitely, given nominal power and cooling.
+The remaining rows show what maximum turbo frequency is possible
+depending on the number of idle cores.  Note that this information is
+not available on all processors.
+.SH FORK EXAMPLE
+If turbostat is invoked with a command, it will fork that command
+and output the statistics gathered when the command exits.
+eg. Here a cycle soaker is run on 1 CPU (see %c0) for a few seconds
+until ^C while the other CPUs are mostly idle:
+
+.nf
+[root@x980 lenb]# ./turbostat cat /dev/zero > /dev/null
+
+^Ccore CPU   %c0   GHz  TSC   %c1    %c3    %c6   %pc3   %pc6
+           8.49 3.63 3.38  16.23   0.66  74.63   0.00   0.00
+   0   0   1.22 3.62 3.38  32.18   0.00  66.60   0.00   0.00
+   0   6   0.40 3.61 3.38  33.00   0.00  66.60   0.00   0.00
+   1   2   0.11 3.14 3.38   0.19   3.95  95.75   0.00   0.00
+   1   8   0.05 2.88 3.38   0.25   3.95  95.75   0.00   0.00
+   2   4   0.00 3.13 3.38   0.02   0.00  99.98   0.00   0.00
+   2  10   0.00 3.09 3.38   0.02   0.00  99.98   0.00   0.00
+   8   1   0.04 3.50 3.38  14.43   0.00  85.54   0.00   0.00
+   8   7   0.03 2.98 3.38  14.43   0.00  85.54   0.00   0.00
+   9   3   0.00 3.16 3.38 100.00   0.00   0.00   0.00   0.00
+   9   9  99.93 3.63 3.38   0.06   0.00   0.00   0.00   0.00
+  10   5   0.01 2.82 3.38   0.08   0.00  99.91   0.00   0.00
+  10  11   0.02 3.36 3.38   0.06   0.00  99.91   0.00   0.00
+6.950866 sec
+
+.fi
+Above the cycle soaker drives cpu9 up 3.6 Ghz turbo limit
+while the other processors are generally in various states of idle.
+
+Note that cpu3 is an HT sibling sharing core9
+with cpu9, and thus it is unable to get to an idle state
+deeper than c1 while cpu9 is busy.
+
+Note that turbostat reports average GHz of 3.61, while
+the arithmetic average of the GHz column above is 3.24.
+This is a weighted average, where the weight is %c0.  ie. it is the total number of
+un-halted cycles elapsed per time divided by the number of CPUs.
+.SH NOTES
+
+.B "turbostat "
+must be run as root.
+
+.B "turbostat "
+reads hardware counters, but doesn't write them.
+So it will not interfere with the OS or other programs, including
+multiple invocations of itself.
+
+\fBturbostat \fP
+may work poorly on Linux-2.6.20 through 2.6.29,
+as \fBacpi-cpufreq \fPperiodically cleared the APERF and MPERF
+in those kernels.
+
+The APERF, MPERF MSRs are defined to count non-halted cycles.
+Although it is not guaranteed by the architecture, turbostat assumes
+that they count at TSC rate, which is true on all processors tested to date.
+
+.SH REFERENCES
+"Intel® Turbo Boost Technology
+in Intel® Core™ Microarchitecture (Nehalem) Based Processors"
+http://download.intel.com/design/processor/applnots/320354.pdf
+
+"Intel® 64 and IA-32 Architectures Software Developer's Manual
+Volume 3B: System Programming Guide"
+http://www.intel.com/products/processor/manuals/
+
+.SH FILES
+.ta
+.nf
+/dev/cpu/*/msr
+.fi
+
+.SH "SEE ALSO"
+msr(4), vmstat(8)
+.PP
+.SH AUTHORS
+.nf
+Written by Len Brown <len.brown@intel.com>
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
new file mode 100644
index 00000000000..4c6983de6fd
--- /dev/null
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -0,0 +1,1048 @@
+/*
+ * turbostat -- show CPU frequency and C-state residency
+ * on modern Intel turbo-capable processors.
+ *
+ * Copyright (c) 2010, Intel Corporation.
+ * Len Brown <len.brown@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <sys/resource.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <string.h>
+#include <ctype.h>
+
+#define MSR_TSC	0x10
+#define MSR_NEHALEM_PLATFORM_INFO	0xCE
+#define MSR_NEHALEM_TURBO_RATIO_LIMIT	0x1AD
+#define MSR_APERF	0xE8
+#define MSR_MPERF	0xE7
+#define MSR_PKG_C2_RESIDENCY	0x60D	/* SNB only */
+#define MSR_PKG_C3_RESIDENCY	0x3F8
+#define MSR_PKG_C6_RESIDENCY	0x3F9
+#define MSR_PKG_C7_RESIDENCY	0x3FA	/* SNB only */
+#define MSR_CORE_C3_RESIDENCY	0x3FC
+#define MSR_CORE_C6_RESIDENCY	0x3FD
+#define MSR_CORE_C7_RESIDENCY	0x3FE	/* SNB only */
+
+char *proc_stat = "/proc/stat";
+unsigned int interval_sec = 5;	/* set with -i interval_sec */
+unsigned int verbose;		/* set with -v */
+unsigned int skip_c0;
+unsigned int skip_c1;
+unsigned int do_nhm_cstates;
+unsigned int do_snb_cstates;
+unsigned int has_aperf;
+unsigned int units = 1000000000;	/* Ghz 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 extra_msr_offset;
+double bclk;
+unsigned int show_pkg;
+unsigned int show_core;
+unsigned int show_cpu;
+
+int aperf_mperf_unstable;
+int backwards_count;
+char *progname;
+int need_reinitialize;
+
+int num_cpus;
+
+typedef struct per_cpu_counters {
+	unsigned long long tsc;		/* per thread */
+	unsigned long long aperf;	/* per thread */
+	unsigned long long mperf;	/* per thread */
+	unsigned long long c1;	/* per thread (calculated) */
+	unsigned long long c3;	/* per core */
+	unsigned long long c6;	/* per core */
+	unsigned long long c7;	/* per core */
+	unsigned long long pc2;	/* per package */
+	unsigned long long pc3;	/* per package */
+	unsigned long long pc6;	/* per package */
+	unsigned long long pc7;	/* per package */
+	unsigned long long extra_msr;	/* per thread */
+	int pkg;
+	int core;
+	int cpu;
+	struct per_cpu_counters *next;
+} PCC;
+
+PCC *pcc_even;
+PCC *pcc_odd;
+PCC *pcc_delta;
+PCC *pcc_average;
+struct timeval tv_even;
+struct timeval tv_odd;
+struct timeval tv_delta;
+
+unsigned long long get_msr(int cpu, off_t offset)
+{
+	ssize_t retval;
+	unsigned long long msr;
+	char pathname[32];
+	int fd;
+
+	sprintf(pathname, "/dev/cpu/%d/msr", cpu);
+	fd = open(pathname, O_RDONLY);
+	if (fd < 0) {
+		perror(pathname);
+		need_reinitialize = 1;
+		return 0;
+	}
+
+	retval = pread(fd, &msr, sizeof msr, offset);
+	if (retval != sizeof msr) {
+		fprintf(stderr, "cpu%d pread(..., 0x%zx) = %jd\n",
+			cpu, offset, retval);
+		exit(-2);
+	}
+
+	close(fd);
+	return msr;
+}
+
+void print_header()
+{
+	if (show_pkg)
+		fprintf(stderr, "pkg ");
+	if (show_core)
+		fprintf(stderr, "core");
+	if (show_cpu)
+		fprintf(stderr, " CPU");
+	if (do_nhm_cstates)
+		fprintf(stderr, "   %%c0 ");
+	if (has_aperf)
+		fprintf(stderr, "  GHz");
+	fprintf(stderr, "  TSC");
+	if (do_nhm_cstates)
+		fprintf(stderr, "   %%c1 ");
+	if (do_nhm_cstates)
+		fprintf(stderr, "   %%c3 ");
+	if (do_nhm_cstates)
+		fprintf(stderr, "   %%c6 ");
+	if (do_snb_cstates)
+		fprintf(stderr, "   %%c7 ");
+	if (do_snb_cstates)
+		fprintf(stderr, "  %%pc2 ");
+	if (do_nhm_cstates)
+		fprintf(stderr, "  %%pc3 ");
+	if (do_nhm_cstates)
+		fprintf(stderr, "  %%pc6 ");
+	if (do_snb_cstates)
+		fprintf(stderr, "  %%pc7 ");
+	if (extra_msr_offset)
+		fprintf(stderr, "       MSR 0x%x ", extra_msr_offset);
+
+	putc('\n', stderr);
+}
+
+void dump_pcc(PCC *pcc)
+{
+	fprintf(stderr, "package: %d ", pcc->pkg);
+	fprintf(stderr, "core:: %d ", pcc->core);
+	fprintf(stderr, "CPU: %d ", pcc->cpu);
+	fprintf(stderr, "TSC: %016llX\n", pcc->tsc);
+	fprintf(stderr, "c3: %016llX\n", pcc->c3);
+	fprintf(stderr, "c6: %016llX\n", pcc->c6);
+	fprintf(stderr, "c7: %016llX\n", pcc->c7);
+	fprintf(stderr, "aperf: %016llX\n", pcc->aperf);
+	fprintf(stderr, "pc2: %016llX\n", pcc->pc2);
+	fprintf(stderr, "pc3: %016llX\n", pcc->pc3);
+	fprintf(stderr, "pc6: %016llX\n", pcc->pc6);
+	fprintf(stderr, "pc7: %016llX\n", pcc->pc7);
+	fprintf(stderr, "msr0x%x: %016llX\n", extra_msr_offset, pcc->extra_msr);
+}
+
+void dump_list(PCC *pcc)
+{
+	printf("dump_list 0x%p\n", pcc);
+
+	for (; pcc; pcc = pcc->next)
+		dump_pcc(pcc);
+}
+
+void print_pcc(PCC *p)
+{
+	double interval_float;
+
+	interval_float = tv_delta.tv_sec + tv_delta.tv_usec/1000000.0;
+
+	/* topology columns, print blanks on 1st (average) line */
+	if (p == pcc_average) {
+		if (show_pkg)
+			fprintf(stderr, "    ");
+		if (show_core)
+			fprintf(stderr, "    ");
+		if (show_cpu)
+			fprintf(stderr, "    ");
+	} else {
+		if (show_pkg)
+			fprintf(stderr, "%4d", p->pkg);
+		if (show_core)
+			fprintf(stderr, "%4d", p->core);
+		if (show_cpu)
+			fprintf(stderr, "%4d", p->cpu);
+	}
+
+	/* %c0 */
+	if (do_nhm_cstates) {
+		if (!skip_c0)
+			fprintf(stderr, "%7.2f", 100.0 * p->mperf/p->tsc);
+		else
+			fprintf(stderr, "   ****");
+	}
+
+	/* GHz */
+	if (has_aperf) {
+		if (!aperf_mperf_unstable) {
+			fprintf(stderr, "%5.2f",
+				1.0 * p->tsc / units * p->aperf /
+				p->mperf / interval_float);
+		} else {
+			if (p->aperf > p->tsc || p->mperf > p->tsc) {
+				fprintf(stderr, " ****");
+			} else {
+				fprintf(stderr, "%4.1f*",
+					1.0 * p->tsc /
+					units * p->aperf /
+					p->mperf / interval_float);
+			}
+		}
+	}
+
+	/* TSC */
+	fprintf(stderr, "%5.2f", 1.0 * p->tsc/units/interval_float);
+
+	if (do_nhm_cstates) {
+		if (!skip_c1)
+			fprintf(stderr, "%7.2f", 100.0 * p->c1/p->tsc);
+		else
+			fprintf(stderr, "   ****");
+	}
+	if (do_nhm_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->c3/p->tsc);
+	if (do_nhm_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->c6/p->tsc);
+	if (do_snb_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->c7/p->tsc);
+	if (do_snb_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->pc2/p->tsc);
+	if (do_nhm_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->pc3/p->tsc);
+	if (do_nhm_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->pc6/p->tsc);
+	if (do_snb_cstates)
+		fprintf(stderr, "%7.2f", 100.0 * p->pc7/p->tsc);
+	if (extra_msr_offset)
+		fprintf(stderr, "  0x%016llx", p->extra_msr);
+	putc('\n', stderr);
+}
+
+void print_counters(PCC *cnt)
+{
+	PCC *pcc;
+
+	print_header();
+
+	if (num_cpus > 1)
+		print_pcc(pcc_average);
+
+	for (pcc = cnt; pcc != NULL; pcc = pcc->next)
+		print_pcc(pcc);
+
+}
+
+#define SUBTRACT_COUNTER(after, before, delta) (delta = (after - before), (before > after))
+
+
+int compute_delta(PCC *after, PCC *before, PCC *delta)
+{
+	int errors = 0;
+	int perf_err = 0;
+
+	skip_c0 = skip_c1 = 0;
+
+	for ( ; after && before && delta;
+		after = after->next, before = before->next, delta = delta->next) {
+		if (before->cpu != after->cpu) {
+			printf("cpu configuration changed: %d != %d\n",
+				before->cpu, after->cpu);
+			return -1;
+		}
+
+		if (SUBTRACT_COUNTER(after->tsc, before->tsc, delta->tsc)) {
+			fprintf(stderr, "cpu%d TSC went backwards %llX to %llX\n",
+				before->cpu, before->tsc, after->tsc);
+			errors++;
+		}
+		/* check for TSC < 1 Mcycles over interval */
+		if (delta->tsc < (1000 * 1000)) {
+			fprintf(stderr, "Insanely slow TSC rate,"
+				" TSC stops in idle?\n");
+			fprintf(stderr, "You can disable all c-states"
+				" by booting with \"idle=poll\"\n");
+			fprintf(stderr, "or just the deep ones with"
+				" \"processor.max_cstate=1\"\n");
+			exit(-3);
+		}
+		if (SUBTRACT_COUNTER(after->c3, before->c3, delta->c3)) {
+			fprintf(stderr, "cpu%d c3 counter went backwards %llX to %llX\n",
+				before->cpu, before->c3, after->c3);
+			errors++;
+		}
+		if (SUBTRACT_COUNTER(after->c6, before->c6, delta->c6)) {
+			fprintf(stderr, "cpu%d c6 counter went backwards %llX to %llX\n",
+				before->cpu, before->c6, after->c6);
+			errors++;
+		}
+		if (SUBTRACT_COUNTER(after->c7, before->c7, delta->c7)) {
+			fprintf(stderr, "cpu%d c7 counter went backwards %llX to %llX\n",
+				before->cpu, before->c7, after->c7);
+			errors++;
+		}
+		if (SUBTRACT_COUNTER(after->pc2, before->pc2, delta->pc2)) {
+			fprintf(stderr, "cpu%d pc2 counter went backwards %llX to %llX\n",
+				before->cpu, before->pc2, after->pc2);
+			errors++;
+		}
+		if (SUBTRACT_COUNTER(after->pc3, before->pc3, delta->pc3)) {
+			fprintf(stderr, "cpu%d pc3 counter went backwards %llX to %llX\n",
+				before->cpu, before->pc3, after->pc3);
+			errors++;
+		}
+		if (SUBTRACT_COUNTER(after->pc6, before->pc6, delta->pc6)) {
+			fprintf(stderr, "cpu%d pc6 counter went backwards %llX to %llX\n",
+				before->cpu, before->pc6, after->pc6);
+			errors++;
+		}
+		if (SUBTRACT_COUNTER(after->pc7, before->pc7, delta->pc7)) {
+			fprintf(stderr, "cpu%d pc7 counter went backwards %llX to %llX\n",
+				before->cpu, before->pc7, after->pc7);
+			errors++;
+		}
+
+		perf_err = SUBTRACT_COUNTER(after->aperf, before->aperf, delta->aperf);
+		if (perf_err) {
+			fprintf(stderr, "cpu%d aperf counter went backwards %llX to %llX\n",
+				before->cpu, before->aperf, after->aperf);
+		}
+		perf_err |= SUBTRACT_COUNTER(after->mperf, before->mperf, delta->mperf);
+		if (perf_err) {
+			fprintf(stderr, "cpu%d mperf counter went backwards %llX to %llX\n",
+				before->cpu, before->mperf, after->mperf);
+		}
+		if (perf_err) {
+			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;
+			}
+			/*
+			 * mperf delta is likely a huge "positive" number
+			 * can not use it for calculating c0 time
+			 */
+			skip_c0 = 1;
+			skip_c1 = 1;
+		}
+
+		/*
+		 * As mperf and tsc collection are not atomic,
+		 * it is possible for mperf's non-halted cycles
+		 * to exceed TSC's all cycles: show c1 = 0% in that case.
+		 */
+		if (delta->mperf > delta->tsc)
+			delta->c1 = 0;
+		else /* normal case, derive c1 */
+			delta->c1 = delta->tsc - delta->mperf
+				- delta->c3 - delta->c6 - delta->c7;
+
+		if (delta->mperf == 0)
+			delta->mperf = 1;	/* divide by 0 protection */
+
+		/*
+		 * for "extra msr", just copy the latest w/o subtracting
+		 */
+		delta->extra_msr = after->extra_msr;
+		if (errors) {
+			fprintf(stderr, "ERROR cpu%d before:\n", before->cpu);
+			dump_pcc(before);
+			fprintf(stderr, "ERROR cpu%d after:\n", before->cpu);
+			dump_pcc(after);
+			errors = 0;
+		}
+	}
+	return 0;
+}
+
+void compute_average(PCC *delta, PCC *avg)
+{
+	PCC *sum;
+
+	sum = calloc(1, sizeof(PCC));
+	if (sum == NULL) {
+		perror("calloc sum");
+		exit(1);
+	}
+
+	for (; delta; delta = delta->next) {
+		sum->tsc += delta->tsc;
+		sum->c1 += delta->c1;
+		sum->c3 += delta->c3;
+		sum->c6 += delta->c6;
+		sum->c7 += delta->c7;
+		sum->aperf += delta->aperf;
+		sum->mperf += delta->mperf;
+		sum->pc2 += delta->pc2;
+		sum->pc3 += delta->pc3;
+		sum->pc6 += delta->pc6;
+		sum->pc7 += delta->pc7;
+	}
+	avg->tsc = sum->tsc/num_cpus;
+	avg->c1 = sum->c1/num_cpus;
+	avg->c3 = sum->c3/num_cpus;
+	avg->c6 = sum->c6/num_cpus;
+	avg->c7 = sum->c7/num_cpus;
+	avg->aperf = sum->aperf/num_cpus;
+	avg->mperf = sum->mperf/num_cpus;
+	avg->pc2 = sum->pc2/num_cpus;
+	avg->pc3 = sum->pc3/num_cpus;
+	avg->pc6 = sum->pc6/num_cpus;
+	avg->pc7 = sum->pc7/num_cpus;
+
+	free(sum);
+}
+
+void get_counters(PCC *pcc)
+{
+	for ( ; pcc; pcc = pcc->next) {
+		pcc->tsc = get_msr(pcc->cpu, MSR_TSC);
+		if (do_nhm_cstates)
+			pcc->c3 = get_msr(pcc->cpu, MSR_CORE_C3_RESIDENCY);
+		if (do_nhm_cstates)
+			pcc->c6 = get_msr(pcc->cpu, MSR_CORE_C6_RESIDENCY);
+		if (do_snb_cstates)
+			pcc->c7 = get_msr(pcc->cpu, MSR_CORE_C7_RESIDENCY);
+		if (has_aperf)
+			pcc->aperf = get_msr(pcc->cpu, MSR_APERF);
+		if (has_aperf)
+			pcc->mperf = get_msr(pcc->cpu, MSR_MPERF);
+		if (do_snb_cstates)
+			pcc->pc2 = get_msr(pcc->cpu, MSR_PKG_C2_RESIDENCY);
+		if (do_nhm_cstates)
+			pcc->pc3 = get_msr(pcc->cpu, MSR_PKG_C3_RESIDENCY);
+		if (do_nhm_cstates)
+			pcc->pc6 = get_msr(pcc->cpu, MSR_PKG_C6_RESIDENCY);
+		if (do_snb_cstates)
+			pcc->pc7 = get_msr(pcc->cpu, MSR_PKG_C7_RESIDENCY);
+		if (extra_msr_offset)
+			pcc->extra_msr = get_msr(pcc->cpu, extra_msr_offset);
+	}
+}
+
+
+void print_nehalem_info()
+{
+	unsigned long long msr;
+	unsigned int ratio;
+
+	if (!do_nehalem_platform_info)
+		return;
+
+	msr = get_msr(0, MSR_NEHALEM_PLATFORM_INFO);
+
+	ratio = (msr >> 40) & 0xFF;
+	fprintf(stderr, "%d * %.0f = %.0f MHz max efficiency\n",
+		ratio, bclk, ratio * bclk);
+
+	ratio = (msr >> 8) & 0xFF;
+	fprintf(stderr, "%d * %.0f = %.0f MHz TSC frequency\n",
+		ratio, bclk, ratio * bclk);
+
+	if (verbose > 1)
+		fprintf(stderr, "MSR_NEHALEM_PLATFORM_INFO: 0x%llx\n", msr);
+
+	if (!do_nehalem_turbo_ratio_limit)
+		return;
+
+	msr = get_msr(0, MSR_NEHALEM_TURBO_RATIO_LIMIT);
+
+	ratio = (msr >> 24) & 0xFF;
+	if (ratio)
+		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 4 active cores\n",
+			ratio, bclk, ratio * bclk);
+
+	ratio = (msr >> 16) & 0xFF;
+	if (ratio)
+		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 3 active cores\n",
+			ratio, bclk, ratio * bclk);
+
+	ratio = (msr >> 8) & 0xFF;
+	if (ratio)
+		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 2 active cores\n",
+			ratio, bclk, ratio * bclk);
+
+	ratio = (msr >> 0) & 0xFF;
+	if (ratio)
+		fprintf(stderr, "%d * %.0f = %.0f MHz max turbo 1 active cores\n",
+			ratio, bclk, ratio * bclk);
+
+}
+
+void free_counter_list(PCC *list)
+{
+	PCC *p;
+
+	for (p = list; p; ) {
+		PCC *free_me;
+
+		free_me = p;
+		p = p->next;
+		free(free_me);
+	}
+	return;
+}
+
+void free_all_counters(void)
+{
+	free_counter_list(pcc_even);
+	pcc_even = NULL;
+
+	free_counter_list(pcc_odd);
+	pcc_odd = NULL;
+
+	free_counter_list(pcc_delta);
+	pcc_delta = NULL;
+
+	free_counter_list(pcc_average);
+	pcc_average = NULL;
+}
+
+void insert_cpu_counters(PCC **list, PCC *new)
+{
+	PCC *prev;
+
+	/*
+	 * list was empty
+	 */
+	if (*list == NULL) {
+		new->next = *list;
+		*list = new;
+		return;
+	}
+
+	show_cpu = 1;	/* there is more than one CPU */
+
+	/*
+	 * insert on front of list.
+	 * It is sorted by ascending package#, core#, cpu#
+	 */
+	if (((*list)->pkg > new->pkg) ||
+	    (((*list)->pkg == new->pkg) && ((*list)->core > new->core)) ||
+	    (((*list)->pkg == new->pkg) && ((*list)->core == new->core) && ((*list)->cpu > new->cpu))) {
+		new->next = *list;
+		*list = new;
+		return;
+	}
+
+	prev = *list;
+
+	while (prev->next && (prev->next->pkg < new->pkg)) {
+		prev = prev->next;
+		show_pkg = 1;	/* there is more than 1 package */
+	}
+
+	while (prev->next && (prev->next->pkg == new->pkg)
+		&& (prev->next->core < new->core)) {
+		prev = prev->next;
+		show_core = 1;	/* there is more than 1 core */
+	}
+
+	while (prev->next && (prev->next->pkg == new->pkg)
+		&& (prev->next->core == new->core)
+		&& (prev->next->cpu < new->cpu)) {
+		prev = prev->next;
+	}
+
+	/*
+	 * insert after "prev"
+	 */
+	new->next = prev->next;
+	prev->next = new;
+
+	return;
+}
+
+void alloc_new_cpu_counters(int pkg, int core, int cpu)
+{
+	PCC *new;
+
+	if (verbose > 1)
+		printf("pkg%d core%d, cpu%d\n", pkg, core, cpu);
+
+	new = (PCC *)calloc(1, sizeof(PCC));
+	if (new == NULL) {
+		perror("calloc");
+		exit(1);
+	}
+	new->pkg = pkg;
+	new->core = core;
+	new->cpu = cpu;
+	insert_cpu_counters(&pcc_odd, new);
+
+	new = (PCC *)calloc(1, sizeof(PCC));
+	if (new == NULL) {
+		perror("calloc");
+		exit(1);
+	}
+	new->pkg = pkg;
+	new->core = core;
+	new->cpu = cpu;
+	insert_cpu_counters(&pcc_even, new);
+
+	new = (PCC *)calloc(1, sizeof(PCC));
+	if (new == NULL) {
+		perror("calloc");
+		exit(1);
+	}
+	new->pkg = pkg;
+	new->core = core;
+	new->cpu = cpu;
+	insert_cpu_counters(&pcc_delta, new);
+
+	new = (PCC *)calloc(1, sizeof(PCC));
+	if (new == NULL) {
+		perror("calloc");
+		exit(1);
+	}
+	new->pkg = pkg;
+	new->core = core;
+	new->cpu = cpu;
+	pcc_average = new;
+}
+
+int get_physical_package_id(int cpu)
+{
+	char path[64];
+	FILE *filep;
+	int pkg;
+
+	sprintf(path, "/sys/devices/system/cpu/cpu%d/topology/physical_package_id", cpu);
+	filep = fopen(path, "r");
+	if (filep == NULL) {
+		perror(path);
+		exit(1);
+	}
+	fscanf(filep, "%d", &pkg);
+	fclose(filep);
+	return pkg;
+}
+
+int get_core_id(int cpu)
+{
+	char path[64];
+	FILE *filep;
+	int core;
+
+	sprintf(path, "/sys/devices/system/cpu/cpu%d/topology/core_id", cpu);
+	filep = fopen(path, "r");
+	if (filep == NULL) {
+		perror(path);
+		exit(1);
+	}
+	fscanf(filep, "%d", &core);
+	fclose(filep);
+	return core;
+}
+
+/*
+ * run func(index, cpu) on every cpu in /proc/stat
+ */
+
+int for_all_cpus(void (func)(int, int, int))
+{
+	FILE *fp;
+	int cpu_count;
+	int retval;
+
+	fp = fopen(proc_stat, "r");
+	if (fp == NULL) {
+		perror(proc_stat);
+		exit(1);
+	}
+
+	retval = fscanf(fp, "cpu %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d\n");
+	if (retval != 0) {
+		perror("/proc/stat format");
+		exit(1);
+	}
+
+	for (cpu_count = 0; ; cpu_count++) {
+		int cpu;
+
+		retval = fscanf(fp, "cpu%u %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d\n", &cpu);
+		if (retval != 1)
+			break;
+
+		func(get_physical_package_id(cpu), get_core_id(cpu), cpu);
+	}
+	fclose(fp);
+	return cpu_count;
+}
+
+void re_initialize(void)
+{
+	printf("turbostat: topology changed, re-initializing.\n");
+	free_all_counters();
+	num_cpus = for_all_cpus(alloc_new_cpu_counters);
+	need_reinitialize = 0;
+	printf("num_cpus is now %d\n", num_cpus);
+}
+
+void dummy(int pkg, int core, int cpu) { return; }
+/*
+ * check to see if a cpu came on-line
+ */
+void verify_num_cpus()
+{
+	int new_num_cpus;
+
+	new_num_cpus = for_all_cpus(dummy);
+
+	if (new_num_cpus != num_cpus) {
+		if (verbose)
+			printf("num_cpus was %d, is now  %d\n",
+				num_cpus, new_num_cpus);
+		need_reinitialize = 1;
+	}
+
+	return;
+}
+
+void turbostat_loop()
+{
+restart:
+	get_counters(pcc_even);
+	gettimeofday(&tv_even, (struct timezone *)NULL);
+
+	while (1) {
+		verify_num_cpus();
+		if (need_reinitialize) {
+			re_initialize();
+			goto restart;
+		}
+		sleep(interval_sec);
+		get_counters(pcc_odd);
+		gettimeofday(&tv_odd, (struct timezone *)NULL);
+
+		compute_delta(pcc_odd, pcc_even, pcc_delta);
+		timersub(&tv_odd, &tv_even, &tv_delta);
+		compute_average(pcc_delta, pcc_average);
+		print_counters(pcc_delta);
+		if (need_reinitialize) {
+			re_initialize();
+			goto restart;
+		}
+		sleep(interval_sec);
+		get_counters(pcc_even);
+		gettimeofday(&tv_even, (struct timezone *)NULL);
+		compute_delta(pcc_even, pcc_odd, pcc_delta);
+		timersub(&tv_even, &tv_odd, &tv_delta);
+		compute_average(pcc_delta, pcc_average);
+		print_counters(pcc_delta);
+	}
+}
+
+void check_dev_msr()
+{
+	struct stat sb;
+
+	if (stat("/dev/cpu/0/msr", &sb)) {
+		fprintf(stderr, "no /dev/cpu/0/msr\n");
+		fprintf(stderr, "Try \"# modprobe msr\"\n");
+		exit(-5);
+	}
+}
+
+void check_super_user()
+{
+	if (getuid() != 0) {
+		fprintf(stderr, "must be root\n");
+		exit(-6);
+	}
+}
+
+int has_nehalem_turbo_ratio_limit(unsigned int family, unsigned int model)
+{
+	if (!genuine_intel)
+		return 0;
+
+	if (family != 6)
+		return 0;
+
+	switch (model) {
+	case 0x1A:	/* Core i7, Xeon 5500 series - Bloomfield, Gainstown NHM-EP */
+	case 0x1E:	/* Core i7 and i5 Processor - Clarksfield, Lynnfield, Jasper Forest */
+	case 0x1F:	/* Core i7 and i5 Processor - Nehalem */
+	case 0x25:	/* Westmere Client - Clarkdale, Arrandale */
+	case 0x2C:	/* Westmere EP - Gulftown */
+	case 0x2A:	/* SNB */
+	case 0x2D:	/* SNB Xeon */
+		return 1;
+	case 0x2E:	/* Nehalem-EX Xeon - Beckton */
+	case 0x2F:	/* Westmere-EX Xeon - Eagleton */
+	default:
+		return 0;
+	}
+}
+
+int is_snb(unsigned int family, unsigned int model)
+{
+	if (!genuine_intel)
+		return 0;
+
+	switch (model) {
+	case 0x2A:
+	case 0x2D:
+		return 1;
+	}
+	return 0;
+}
+
+double discover_bclk(unsigned int family, unsigned int model)
+{
+	if (is_snb(family, model))
+		return 100.00;
+	else
+		return 133.33;
+}
+
+void check_cpuid()
+{
+	unsigned int eax, ebx, ecx, edx, max_level;
+	unsigned int fms, family, model, stepping;
+
+	eax = ebx = ecx = edx = 0;
+
+	asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0));
+
+	if (ebx == 0x756e6547 && edx == 0x49656e69 && ecx == 0x6c65746e)
+		genuine_intel = 1;
+
+	if (verbose)
+		fprintf(stderr, "%.4s%.4s%.4s ",
+			(char *)&ebx, (char *)&edx, (char *)&ecx);
+
+	asm("cpuid" : "=a" (fms), "=c" (ecx), "=d" (edx) : "a" (1) : "ebx");
+	family = (fms >> 8) & 0xf;
+	model = (fms >> 4) & 0xf;
+	stepping = fms & 0xf;
+	if (family == 6 || family == 0xf)
+		model += ((fms >> 16) & 0xf) << 4;
+
+	if (verbose)
+		fprintf(stderr, "%d CPUID levels; family:model:stepping 0x%x:%x:%x (%d:%d:%d)\n",
+			max_level, family, model, stepping, family, model, stepping);
+
+	if (!(edx & (1 << 5))) {
+		fprintf(stderr, "CPUID: no MSR\n");
+		exit(1);
+	}
+
+	/*
+	 * check max extended function levels of CPUID.
+	 * This is needed to check for invariant TSC.
+	 * This check is valid for both Intel and AMD.
+	 */
+	ebx = ecx = edx = 0;
+	asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x80000000));
+
+	if (max_level < 0x80000007) {
+		fprintf(stderr, "CPUID: no invariant TSC (max_level 0x%x)\n", max_level);
+		exit(1);
+	}
+
+	/*
+	 * Non-Stop TSC is advertised by CPUID.EAX=0x80000007: EDX.bit8
+	 * this check is valid for both Intel and AMD
+	 */
+	asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x80000007));
+	has_invariant_tsc = edx && (1 << 8);
+
+	if (!has_invariant_tsc) {
+		fprintf(stderr, "No invariant TSC\n");
+		exit(1);
+	}
+
+	/*
+	 * APERF/MPERF is advertised by CPUID.EAX=0x6: ECX.bit0
+	 * this check is valid for both Intel and AMD
+	 */
+
+	asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x6));
+	has_aperf = ecx && (1 << 0);
+	if (!has_aperf) {
+		fprintf(stderr, "No APERF MSR\n");
+		exit(1);
+	}
+
+	do_nehalem_platform_info = genuine_intel && has_invariant_tsc;
+	do_nhm_cstates = genuine_intel;	/* all Intel w/ non-stop TSC have NHM counters */
+	do_snb_cstates = is_snb(family, model);
+	bclk = discover_bclk(family, model);
+
+	do_nehalem_turbo_ratio_limit = has_nehalem_turbo_ratio_limit(family, model);
+}
+
+
+void usage()
+{
+	fprintf(stderr, "%s: [-v] [-M MSR#] [-i interval_sec | command ...]\n",
+		progname);
+	exit(1);
+}
+
+
+/*
+ * in /dev/cpu/ return success for names that are numbers
+ * ie. filter out ".", "..", "microcode".
+ */
+int dir_filter(const struct dirent *dirp)
+{
+	if (isdigit(dirp->d_name[0]))
+		return 1;
+	else
+		return 0;
+}
+
+int open_dev_cpu_msr(int dummy1)
+{
+	return 0;
+}
+
+void turbostat_init()
+{
+	check_cpuid();
+
+	check_dev_msr();
+	check_super_user();
+
+	num_cpus = for_all_cpus(alloc_new_cpu_counters);
+
+	if (verbose)
+		print_nehalem_info();
+}
+
+int fork_it(char **argv)
+{
+	int retval;
+	pid_t child_pid;
+	get_counters(pcc_even);
+	gettimeofday(&tv_even, (struct timezone *)NULL);
+
+	child_pid = fork();
+	if (!child_pid) {
+		/* child */
+		execvp(argv[0], argv);
+	} else {
+		int status;
+
+		/* parent */
+		if (child_pid == -1) {
+			perror("fork");
+			exit(1);
+		}
+
+		signal(SIGINT, SIG_IGN);
+		signal(SIGQUIT, SIG_IGN);
+		if (waitpid(child_pid, &status, 0) == -1) {
+			perror("wait");
+			exit(1);
+		}
+	}
+	get_counters(pcc_odd);
+	gettimeofday(&tv_odd, (struct timezone *)NULL);
+	retval = compute_delta(pcc_odd, pcc_even, pcc_delta);
+
+	timersub(&tv_odd, &tv_even, &tv_delta);
+	compute_average(pcc_delta, pcc_average);
+	if (!retval)
+		print_counters(pcc_delta);
+
+	fprintf(stderr, "%.6f sec\n", tv_delta.tv_sec + tv_delta.tv_usec/1000000.0);;
+
+	return 0;
+}
+
+void cmdline(int argc, char **argv)
+{
+	int opt;
+
+	progname = argv[0];
+
+	while ((opt = getopt(argc, argv, "+vi:M:")) != -1) {
+		switch (opt) {
+		case 'v':
+			verbose++;
+			break;
+		case 'i':
+			interval_sec = atoi(optarg);
+			break;
+		case 'M':
+			sscanf(optarg, "%x", &extra_msr_offset);
+			if (verbose > 1)
+				fprintf(stderr, "MSR 0x%X\n", extra_msr_offset);
+			break;
+		default:
+			usage();
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	cmdline(argc, argv);
+
+	if (verbose > 1)
+		fprintf(stderr, "turbostat Dec 6, 2010"
+			" - Len Brown <lenb@kernel.org>\n");
+	if (verbose > 1)
+		fprintf(stderr, "http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/\n");
+
+	turbostat_init();
+
+	/*
+	 * if any params left, it must be a command to fork
+	 */
+	if (argc - optind)
+		return fork_it(argv + optind);
+	else
+		turbostat_loop();
+
+	return 0;
+}