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Subject[PATCH 41/76] tools turbostat: harden against cpu online/offline
Date
From: Len Brown <len.brown@intel.com>

Sometimes users have turbostat running in interval mode
when they take processors offline/online.

Previously, turbostat would survive, but not gracefully.

Tighten up the error checking so turbostat notices
changesn sooner, and print just 1 line on change:

turbostat: re-initialized with num_cpus %d

Signed-off-by: Len Brown <len.brown@intel.com>
---
tools/power/x86/turbostat/turbostat.c | 115 +++++++++++++++++----------------
1 file changed, 61 insertions(+), 54 deletions(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index fa60872..ab2f682 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -71,7 +71,6 @@ unsigned int show_cpu;
int aperf_mperf_unstable;
int backwards_count;
char *progname;
-int need_reinitialize;

int num_cpus;
cpu_set_t *cpu_mask;
@@ -138,30 +137,24 @@ int cpu_migrate(int cpu)
return 0;
}

-unsigned long long get_msr(int cpu, off_t offset)
+int get_msr(int cpu, off_t offset, unsigned long long *msr)
{
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);
- }
+ if (fd < 0)
+ return -1;

+ retval = pread(fd, msr, sizeof *msr, offset);
close(fd);
- return msr;
+
+ if (retval != sizeof *msr)
+ return -1;
+
+ return 0;
}

void print_header(void)
@@ -506,36 +499,51 @@ void compute_average(struct counters *delta, struct counters *avg)
free(sum);
}

-void get_counters(struct counters *cnt)
+int get_counters(struct counters *cnt)
{
for ( ; cnt; cnt = cnt->next) {
- if (cpu_migrate(cnt->cpu)) {
- need_reinitialize = 1;
- return;
+
+ if (cpu_migrate(cnt->cpu))
+ return -1;
+
+ if (get_msr(cnt->cpu, MSR_TSC, &cnt->tsc))
+ return -1;
+
+ if (has_aperf) {
+ if (get_msr(cnt->cpu, MSR_APERF, &cnt->aperf))
+ return -1;
+ if (get_msr(cnt->cpu, MSR_MPERF, &cnt->mperf))
+ return -1;
+ }
+
+ if (do_nhm_cstates) {
+ if (get_msr(cnt->cpu, MSR_CORE_C3_RESIDENCY, &cnt->c3))
+ return -1;
+ if (get_msr(cnt->cpu, MSR_CORE_C6_RESIDENCY, &cnt->c6))
+ return -1;
}

- cnt->tsc = get_msr(cnt->cpu, MSR_TSC);
- if (do_nhm_cstates)
- cnt->c3 = get_msr(cnt->cpu, MSR_CORE_C3_RESIDENCY);
- if (do_nhm_cstates)
- cnt->c6 = get_msr(cnt->cpu, MSR_CORE_C6_RESIDENCY);
- if (do_snb_cstates)
- cnt->c7 = get_msr(cnt->cpu, MSR_CORE_C7_RESIDENCY);
- if (has_aperf)
- cnt->aperf = get_msr(cnt->cpu, MSR_APERF);
- if (has_aperf)
- cnt->mperf = get_msr(cnt->cpu, MSR_MPERF);
- if (do_snb_cstates)
- cnt->pc2 = get_msr(cnt->cpu, MSR_PKG_C2_RESIDENCY);
- if (do_nhm_cstates)
- cnt->pc3 = get_msr(cnt->cpu, MSR_PKG_C3_RESIDENCY);
- if (do_nhm_cstates)
- cnt->pc6 = get_msr(cnt->cpu, MSR_PKG_C6_RESIDENCY);
if (do_snb_cstates)
- cnt->pc7 = get_msr(cnt->cpu, MSR_PKG_C7_RESIDENCY);
+ if (get_msr(cnt->cpu, MSR_CORE_C7_RESIDENCY, &cnt->c7))
+ return -1;
+
+ if (do_nhm_cstates) {
+ if (get_msr(cnt->cpu, MSR_PKG_C3_RESIDENCY, &cnt->pc3))
+ return -1;
+ if (get_msr(cnt->cpu, MSR_PKG_C6_RESIDENCY, &cnt->pc6))
+ return -1;
+ }
+ if (do_snb_cstates) {
+ if (get_msr(cnt->cpu, MSR_PKG_C2_RESIDENCY, &cnt->pc2))
+ return -1;
+ if (get_msr(cnt->cpu, MSR_PKG_C7_RESIDENCY, &cnt->pc7))
+ return -1;
+ }
if (extra_msr_offset)
- cnt->extra_msr = get_msr(cnt->cpu, extra_msr_offset);
+ if (get_msr(cnt->cpu, extra_msr_offset, &cnt->extra_msr))
+ return -1;
}
+ return 0;
}

void print_nehalem_info(void)
@@ -546,7 +554,7 @@ void print_nehalem_info(void)
if (!do_nehalem_platform_info)
return;

- msr = get_msr(0, MSR_NEHALEM_PLATFORM_INFO);
+ get_msr(0, MSR_NEHALEM_PLATFORM_INFO, &msr);

ratio = (msr >> 40) & 0xFF;
fprintf(stderr, "%d * %.0f = %.0f MHz max efficiency\n",
@@ -562,7 +570,7 @@ void print_nehalem_info(void)
if (!do_nehalem_turbo_ratio_limit)
return;

- msr = get_msr(0, MSR_NEHALEM_TURBO_RATIO_LIMIT);
+ get_msr(0, MSR_NEHALEM_TURBO_RATIO_LIMIT, &msr);

ratio = (msr >> 24) & 0xFF;
if (ratio)
@@ -755,7 +763,7 @@ int get_core_id(int cpu)
}

/*
- * run func(index, cpu) on every cpu in /proc/stat
+ * run func(pkg, core, cpu) on every cpu in /proc/stat
*/

int for_all_cpus(void (func)(int, int, int))
@@ -791,20 +799,18 @@ int for_all_cpus(void (func)(int, int, int))

void re_initialize(void)
{
- printf("turbostat: topology changed, re-initializing.\n");
free_all_counters();
num_cpus = for_all_cpus(alloc_new_counters);
- need_reinitialize = 0;
cpu_mask_uninit();
cpu_mask_init(num_cpus);
- printf("num_cpus is now %d\n", num_cpus);
+ printf("turbostat: re-initialized with num_cpus %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(void)
+int verify_num_cpus(void)
{
int new_num_cpus;

@@ -814,8 +820,9 @@ void verify_num_cpus(void)
if (verbose)
printf("num_cpus was %d, is now %d\n",
num_cpus, new_num_cpus);
- need_reinitialize = 1;
+ return -1;
}
+ return 0;
}

void turbostat_loop()
@@ -825,25 +832,25 @@ restart:
gettimeofday(&tv_even, (struct timezone *)NULL);

while (1) {
- verify_num_cpus();
- if (need_reinitialize) {
+ if (verify_num_cpus()) {
re_initialize();
goto restart;
}
sleep(interval_sec);
- get_counters(cnt_odd);
+ if (get_counters(cnt_odd)) {
+ re_initialize();
+ goto restart;
+ }
gettimeofday(&tv_odd, (struct timezone *)NULL);
-
compute_delta(cnt_odd, cnt_even, cnt_delta);
timersub(&tv_odd, &tv_even, &tv_delta);
compute_average(cnt_delta, cnt_average);
print_counters(cnt_delta);
- if (need_reinitialize) {
+ sleep(interval_sec);
+ if (get_counters(cnt_even)) {
re_initialize();
goto restart;
}
- sleep(interval_sec);
- get_counters(cnt_even);
gettimeofday(&tv_even, (struct timezone *)NULL);
compute_delta(cnt_even, cnt_odd, cnt_delta);
timersub(&tv_even, &tv_odd, &tv_delta);
--
1.7.10.rc2.19.gfae9d


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