tools/power turbostat: Gracefully handle ACPI S3

turbostat gives valid results across suspend to idle, aka freeze,
whether invoked in  interval mode, or in command mode.
Indeed, this can be used to measure suspend to idle:

turbostat echo freeze > /sys/power/state

But this does not work across suspend to ACPI S3, because the
processor counters, including the TSC, are reset on resume.
Further, when turbostat detects a problem, it does't forgive
the hardware, and interval mode will print *'s from there on out.

Instead, upon detecting counters going backwards, simply
reset and start over.

Interval mode across ACPI S3: (observe TSC going backwards)

root@sharkbay:/home/lenb/turbostat-src# ./turbostat -M 0x10
     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz           MSR 0x010
       -       1    0.06     858    2294  0x0000000000000000
       0       0    0.06     847    2294  0x0000002a254b98ac
       1       1    0.06     878    2294  0x0000002a254efa3a
       2       1    0.07     843    2294  0x0000002a2551df65
       3       0    0.05     863    2294  0x0000002a2553fea2
turbostat: re-initialized with num_cpus 4
     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz           MSR 0x010
       -       2    0.20     849    2294  0x0000000000000000
       0       2    0.26     856    2294  0x0000000449abb60d
       1       2    0.20     844    2294  0x0000000449b087ec
       2       2    0.21     850    2294  0x0000000449b35d5d
       3       1    0.12     839    2294  0x0000000449b5fd5a
^C

Command mode across ACPI S3:
root@sharkbay:/home/lenb/turbostat-src# ./turbostat -M 0x10 sleep 10
./turbostat: Counter reset detected
14.196299 sec
Signed-off-by: Len Brown <len.brown@intel.com>

tools/power/x86/turbostat/turbostat.c

@@ -51,8 +51,6 @@ unsigned int debug;
 unsigned int rapl_joules;
 unsigned int summary_only;
 unsigned int dump_only;
-unsigned int skip_c0;
-unsigned int skip_c1;
 unsigned int do_nhm_cstates;
 unsigned int do_snb_cstates;
 unsigned int do_knl_cstates;
@@ -145,7 +143,6 @@ unsigned int has_hwp_pkg;		/* IA32_HWP_REQUEST_PKG */
 
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 
-int aperf_mperf_unstable;
 int backwards_count;
 char *progname;
 
@@ -546,12 +543,8 @@ int format_counters(struct thread_data *t, struct core_data *c,
 			1.0 / units * t->aperf / interval_float);
 
 	/* Busy% */
-	if (has_aperf) {
-		if (!skip_c0)
-			outp += sprintf(outp, "%8.2f", 100.0 * t->mperf/t->tsc/tsc_tweak);
-		else
-			outp += sprintf(outp, "********");
-	}
+	if (has_aperf)
+		outp += sprintf(outp, "%8.2f", 100.0 * t->mperf/t->tsc/tsc_tweak);
 
 	/* Bzy_MHz */
 	if (has_aperf) {
@@ -591,12 +584,8 @@ int format_counters(struct thread_data *t, struct core_data *c,
 	if (do_smi)
 		outp += sprintf(outp, "%8d", t->smi_count);
 
-	if (do_nhm_cstates) {
-		if (!skip_c1)
-			outp += sprintf(outp, "%8.2f", 100.0 * t->c1/t->tsc);
-		else
-			outp += sprintf(outp, "********");
-	}
+	if (do_nhm_cstates)
+		outp += sprintf(outp, "%8.2f", 100.0 * t->c1/t->tsc);
 
 	/* print per-core data only for 1st thread in core */
 	if (!(t->flags & CPU_IS_FIRST_THREAD_IN_CORE))
@@ -622,8 +611,8 @@ int format_counters(struct thread_data *t, struct core_data *c,
 
 	/* GFXrc6 */
 	if (do_gfx_rc6_ms) {
-		if (p->gfx_rc6_ms == -1) {	/* detect counter reset */
-			outp += sprintf(outp, "  ***.**");
+		if (p->gfx_rc6_ms == -1) {	/* detect GFX counter reset */
+			outp += sprintf(outp, "   **.**");
 		} else {
 			outp += sprintf(outp, "%8.2f",
 				p->gfx_rc6_ms / 10.0 / interval_float);
@@ -748,7 +737,7 @@ void format_all_counters(struct thread_data *t, struct core_data *c, struct pkg_
 		old = 0x100000000 + new - old;	\
 	}
 
-void
+int
 delta_package(struct pkg_data *new, struct pkg_data *old)
 {
 
@@ -784,6 +773,8 @@ delta_package(struct pkg_data *new, struct pkg_data *old)
 	DELTA_WRAP32(new->energy_dram, old->energy_dram);
 	DELTA_WRAP32(new->rapl_pkg_perf_status, old->rapl_pkg_perf_status);
 	DELTA_WRAP32(new->rapl_dram_perf_status, old->rapl_dram_perf_status);
+
+	return 0;
 }
 
 void
@@ -798,7 +789,7 @@ delta_core(struct core_data *new, struct core_data *old)
 /*
  * old = new - old
  */
-void
+int
 delta_thread(struct thread_data *new, struct thread_data *old,
 	struct core_data *core_delta)
 {
@@ -817,20 +808,7 @@ delta_thread(struct thread_data *new, struct thread_data *old,
 			old->aperf = new->aperf - old->aperf;
 			old->mperf = new->mperf - old->mperf;
 		} else {
-
-			if (!aperf_mperf_unstable) {
-				fprintf(outf, "%s: APERF or MPERF went backwards *\n", progname);
-				fprintf(outf, "* Frequency results do not cover entire interval *\n");
-				fprintf(outf, "* 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;
+			return -1;
 		}
 	}
 
@@ -877,24 +855,30 @@ delta_thread(struct thread_data *new, struct thread_data *old,
 
 	if (do_smi)
 		old->smi_count = new->smi_count - old->smi_count;
+
+	return 0;
 }
 
 int delta_cpu(struct thread_data *t, struct core_data *c,
 	struct pkg_data *p, struct thread_data *t2,
 	struct core_data *c2, struct pkg_data *p2)
 {
+	int retval = 0;
+
 	/* calculate core delta only for 1st thread in core */
 	if (t->flags & CPU_IS_FIRST_THREAD_IN_CORE)
 		delta_core(c, c2);
 
 	/* always calculate thread delta */
-	delta_thread(t, t2, c2);	/* c2 is core delta */
+	retval = delta_thread(t, t2, c2);	/* c2 is core delta */
+	if (retval)
+		return retval;
 
 	/* calculate package delta only for 1st core in package */
 	if (t->flags & CPU_IS_FIRST_CORE_IN_PACKAGE)
-		delta_package(p, p2);
+		retval = delta_package(p, p2);
 
-	return 0;
+	return retval;
 }
 
 void clear_counters(struct thread_data *t, struct core_data *c, struct pkg_data *p)
@@ -2067,7 +2051,10 @@ void turbostat_loop()
 		}
 		gettimeofday(&tv_odd, (struct timezone *)NULL);
 		timersub(&tv_odd, &tv_even, &tv_delta);
-		for_all_cpus_2(delta_cpu, ODD_COUNTERS, EVEN_COUNTERS);
+		if (for_all_cpus_2(delta_cpu, ODD_COUNTERS, EVEN_COUNTERS)) {
+			re_initialize();
+			goto restart;
+		}
 		compute_average(EVEN_COUNTERS);
 		format_all_counters(EVEN_COUNTERS);
 		flush_output_stdout();
@@ -2083,7 +2070,10 @@ void turbostat_loop()
 		}
 		gettimeofday(&tv_even, (struct timezone *)NULL);
 		timersub(&tv_even, &tv_odd, &tv_delta);
-		for_all_cpus_2(delta_cpu, EVEN_COUNTERS, ODD_COUNTERS);
+		if (for_all_cpus_2(delta_cpu, EVEN_COUNTERS, ODD_COUNTERS)) {
+			re_initialize();
+			goto restart;
+		}
 		compute_average(ODD_COUNTERS);
 		format_all_counters(ODD_COUNTERS);
 		flush_output_stdout();
@@ -3693,9 +3683,12 @@ int fork_it(char **argv)
 	for_all_cpus(get_counters, ODD_COUNTERS);
 	gettimeofday(&tv_odd, (struct timezone *)NULL);
 	timersub(&tv_odd, &tv_even, &tv_delta);
-	for_all_cpus_2(delta_cpu, ODD_COUNTERS, EVEN_COUNTERS);
-	compute_average(EVEN_COUNTERS);
-	format_all_counters(EVEN_COUNTERS);
+	if (for_all_cpus_2(delta_cpu, ODD_COUNTERS, EVEN_COUNTERS))
+		fprintf(outf, "%s: Counter reset detected\n", progname);
+	else {
+		compute_average(EVEN_COUNTERS);
+		format_all_counters(EVEN_COUNTERS);
+	}
 
 	fprintf(outf, "%.6f sec\n", tv_delta.tv_sec + tv_delta.tv_usec/1000000.0);
 
@@ -3722,7 +3715,7 @@ int get_and_dump_counters(void)
 }
 
 void print_version() {
-	fprintf(outf, "turbostat version 4.12 5 Apr 2016"
+	fprintf(outf, "turbostat version 4.13 22 Apr 2016"
 		" - Len Brown <lenb@kernel.org>\n");
 }