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-rw-r--r--tools/power/x86/turbostat/turbostat.866
-rw-r--r--tools/power/x86/turbostat/turbostat.c47
2 files changed, 68 insertions, 45 deletions
diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8
index 56bfb523c5bb..9b950699e63d 100644
--- a/tools/power/x86/turbostat/turbostat.8
+++ b/tools/power/x86/turbostat/turbostat.8
@@ -12,16 +12,16 @@ turbostat \- Report processor frequency and idle statistics
.RB [ "\-i interval_sec" ]
.SH DESCRIPTION
\fBturbostat \fP reports processor topology, frequency,
-idle power-state statistics, temperature and power on modern X86 processors.
-Either \fBcommand\fP is forked and statistics are printed
-upon its completion, or statistics are printed periodically.
-
-\fBturbostat \fP
-must be run on root, and
-minimally requires that the processor
-supports an "invariant" TSC, plus the APERF and MPERF MSRs.
-Additional information is reported depending on hardware counter support.
-
+idle power-state statistics, temperature and power on X86 processors.
+There are two ways to invoke turbostat.
+The first method is to supply a
+\fBcommand\fP, which is forked and statistics are printed
+upon its completion.
+The second method is to omit the command,
+and turbodstat will print statistics every 5 seconds.
+The 5-second interval can changed using the -i option.
+
+Some information is not availalbe on older processors.
.SS Options
The \fB-p\fP option limits output to the 1st thread in 1st core of each package.
.PP
@@ -130,12 +130,13 @@ cpu3: MSR_IA32_THERM_STATUS: 0x884e0000 (27 C +/- 1)
...
.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
+available at the minimum package voltage. The \fBTSC frequency\fP is the base
+frequency of the processor -- this should match the brand string
+in /proc/cpuinfo. This base 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.
+depending on the number of idle cores. Note that not all information is
+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.
@@ -176,6 +177,11 @@ not including any non-busy idle time.
.B "turbostat "
must be run as root.
+Alternatively, non-root users can be enabled to run turbostat this way:
+
+# setcap cap_sys_rawio=ep ./turbostat
+
+# chmod +r /dev/cpu/*/msr
.B "turbostat "
reads hardware counters, but doesn't write them.
@@ -184,15 +190,33 @@ 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
+as \fBacpi-cpufreq \fPperiodically cleared the APERF and MPERF MSRs
in those kernels.
-If the TSC column does not make sense, then
-the other numbers will also make no sense.
-Turbostat is lightweight, and its data collection is not atomic.
-These issues are usually caused by an extremely short measurement
-interval (much less than 1 second), or system activity that prevents
-turbostat from being able to run on all CPUS to quickly collect data.
+AVG_MHz = APERF_delta/measurement_interval. This is the actual
+number of elapsed cycles divided by the entire sample interval --
+including idle time. Note that this calculation is resiliant
+to systems lacking a non-stop TSC.
+
+TSC_MHz = TSC_delta/measurement_interval.
+On a system with an invariant TSC, this value will be constant
+and will closely match the base frequency value shown
+in the brand string in /proc/cpuinfo. On a system where
+the TSC stops in idle, TSC_MHz will drop
+below the processor's base frequency.
+
+%Busy = MPERF_delta/TSC_delta
+
+Bzy_MHz = TSC_delta/APERF_delta/MPERF_delta/measurement_interval
+
+Note that these calculations depend on TSC_delta, so they
+are not reliable during intervals when TSC_MHz is not running at the base frequency.
+
+Turbostat data collection is not atomic.
+Extremely short measurement intervals (much less than 1 second),
+or system activity that prevents turbostat from being able
+to run on all CPUS to quickly collect data, will result in
+inconsistent results.
The APERF, MPERF MSRs are defined to count non-halted cycles.
Although it is not guaranteed by the architecture, turbostat assumes
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index b654b641d4c3..a02c02f25e88 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -673,24 +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;
}
@@ -2244,14 +2246,11 @@ 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");
+ 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);
@@ -2632,7 +2631,7 @@ int main(int argc, char **argv)
cmdline(argc, argv);
if (verbose)
- fprintf(stderr, "turbostat v3.8 14-Aug 2014"
+ fprintf(stderr, "turbostat v3.9 23-Jan, 2015"
" - Len Brown <lenb@kernel.org>\n");
turbostat_init();
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 21:20:02 +0000