mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-13 10:02:38 +00:00
Fix CPU load reporting independent of scheduler used.
- Sample CPU usage data from kern.cp_times, this makes for a far more accurate and scheduler independent algorithm. - Rip out the process list scraping that is no longer required. - Don't update CPU usage sampling on every request, but every 15s instead. This makes it impossible for an attacker to hide the CPU load by triggering 4 samplings in short succession when the system is idle. - After reaching the steady-state, the system will always report the average CPU load of the last 60 sampled seconds. - Untangling of call graph. PR: kern/130222 Tested by: Julian Dunn <jdunn@aquezada.com> Gustau Pérez <gperez@entel.upc.edu> Jürgen Weiß <weiss@uni-mainz.de> MFC after: 2 weeks I'm unsure if some MIB standard states this must be the load average for, eg. 300s, it looks like net-snmp isn't even bothering to implement the CPU load reporting at all.
This commit is contained in:
Ulrich Spörlein
parent
c2ab553ee5
commit
ac203a768d
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=214489
@ -56,19 +56,15 @@
|
||||
struct processor_entry {
|
||||
int32_t index;
|
||||
const struct asn_oid *frwId;
|
||||
int32_t load;
|
||||
int32_t load; /* average cpu usage */
|
||||
int32_t sample_cnt; /* number of usage samples */
|
||||
int32_t cur_sample_idx; /* current valid sample */
|
||||
TAILQ_ENTRY(processor_entry) link;
|
||||
u_char cpu_no; /* which cpu, counted from 0 */
|
||||
pid_t idle_pid; /* PID of idle process for this CPU */
|
||||
|
||||
/* the samples from the last minute, as required by MIB */
|
||||
double samples[MAX_CPU_SAMPLES];
|
||||
|
||||
/* current sample to fill in next time, must be < MAX_CPU_SAMPLES */
|
||||
uint32_t cur_sample_idx;
|
||||
|
||||
/* number of useful samples */
|
||||
uint32_t sample_cnt;
|
||||
long states[MAX_CPU_SAMPLES][CPUSTATES];
|
||||
};
|
||||
TAILQ_HEAD(processor_tbl, processor_entry);
|
||||
|
||||
@ -82,65 +78,78 @@ static int32_t detected_processor_count;
|
||||
/* sysctlbyname(hw.ncpu) */
|
||||
static int hw_ncpu;
|
||||
|
||||
/* sysctlbyname(kern.{ccpu,fscale}) */
|
||||
static fixpt_t ccpu;
|
||||
static int fscale;
|
||||
|
||||
/* tick of PDU where we have refreshed the processor table last */
|
||||
static uint64_t proctbl_tick;
|
||||
/* sysctlbyname(kern.cp_times) */
|
||||
static int cpmib[2];
|
||||
static size_t cplen;
|
||||
|
||||
/* periodic timer used to get cpu load stats */
|
||||
static void *cpus_load_timer;
|
||||
|
||||
/*
|
||||
* Average the samples. The entire algorithm seems to be wrong XXX.
|
||||
/**
|
||||
* Returns the CPU usage of a given processor entry.
|
||||
*
|
||||
* It needs at least two cp_times "tick" samples to calculate a delta and
|
||||
* thus, the usage over the sampling period.
|
||||
*/
|
||||
static int
|
||||
get_avg_load(struct processor_entry *e)
|
||||
{
|
||||
u_int i;
|
||||
double sum = 0.0;
|
||||
u_int i, oldest;
|
||||
long delta = 0;
|
||||
double usage = 0.0;
|
||||
|
||||
assert(e != NULL);
|
||||
|
||||
if (e->sample_cnt == 0)
|
||||
/* Need two samples to perform delta calculation. */
|
||||
if (e->sample_cnt <= 1)
|
||||
return (0);
|
||||
|
||||
for (i = 0; i < e->sample_cnt; i++)
|
||||
sum += e->samples[i];
|
||||
/* Oldest usable index, we wrap around. */
|
||||
if (e->sample_cnt == MAX_CPU_SAMPLES)
|
||||
oldest = (e->cur_sample_idx + 1) % MAX_CPU_SAMPLES;
|
||||
else
|
||||
oldest = 0;
|
||||
|
||||
return ((int)floor((double)sum/(double)e->sample_cnt));
|
||||
}
|
||||
/* Sum delta for all states. */
|
||||
for (i = 0; i < CPUSTATES; i++) {
|
||||
delta += e->states[e->cur_sample_idx][i];
|
||||
delta -= e->states[oldest][i];
|
||||
}
|
||||
if (delta == 0)
|
||||
return 0;
|
||||
|
||||
/*
|
||||
* Stolen from /usr/src/bin/ps/print.c. The idle process should never
|
||||
* be swapped out :-)
|
||||
*/
|
||||
static double
|
||||
processor_getpcpu(struct kinfo_proc *ki_p)
|
||||
{
|
||||
/* Take idle time from the last element and convert to
|
||||
* percent usage by contrasting with total ticks delta. */
|
||||
usage = (double)(e->states[e->cur_sample_idx][CPUSTATES-1] -
|
||||
e->states[oldest][CPUSTATES-1]) / delta;
|
||||
usage = 100 - (usage * 100);
|
||||
HRDBG("CPU no. %d, delta ticks %ld, pct usage %.2f", e->cpu_no,
|
||||
delta, usage);
|
||||
|
||||
if (ccpu == 0 || fscale == 0)
|
||||
return (0.0);
|
||||
|
||||
#define fxtofl(fixpt) ((double)(fixpt) / fscale)
|
||||
return (100.0 * fxtofl(ki_p->ki_pctcpu) /
|
||||
(1.0 - exp(ki_p->ki_swtime * log(fxtofl(ccpu)))));
|
||||
return ((int)(usage));
|
||||
}
|
||||
|
||||
/**
|
||||
* Save a new sample
|
||||
* Save a new sample to proc entry and get the average usage.
|
||||
*
|
||||
* Samples are stored in a ringbuffer from 0..(MAX_CPU_SAMPLES-1)
|
||||
*/
|
||||
static void
|
||||
save_sample(struct processor_entry *e, struct kinfo_proc *kp)
|
||||
save_sample(struct processor_entry *e, long *cp_times)
|
||||
{
|
||||
int i;
|
||||
|
||||
e->samples[e->cur_sample_idx] = 100.0 - processor_getpcpu(kp);
|
||||
e->load = get_avg_load(e);
|
||||
e->cur_sample_idx = (e->cur_sample_idx + 1) % MAX_CPU_SAMPLES;
|
||||
for (i = 0; cp_times != NULL && i < CPUSTATES; i++)
|
||||
e->states[e->cur_sample_idx][i] = cp_times[i];
|
||||
|
||||
if (++e->sample_cnt > MAX_CPU_SAMPLES)
|
||||
e->sample_cnt++;
|
||||
if (e->sample_cnt > MAX_CPU_SAMPLES)
|
||||
e->sample_cnt = MAX_CPU_SAMPLES;
|
||||
|
||||
HRDBG("sample count for CPU no. %d went to %d", e->cpu_no, e->sample_cnt);
|
||||
e->load = get_avg_load(e);
|
||||
|
||||
}
|
||||
|
||||
/**
|
||||
@ -178,8 +187,9 @@ proc_create_entry(u_int cpu_no, struct device_map_entry *map)
|
||||
|
||||
entry->index = map->hrIndex;
|
||||
entry->load = 0;
|
||||
entry->sample_cnt = 0;
|
||||
entry->cur_sample_idx = -1;
|
||||
entry->cpu_no = (u_char)cpu_no;
|
||||
entry->idle_pid = 0;
|
||||
entry->frwId = &oid_zeroDotZero; /* unknown id FIXME */
|
||||
|
||||
INSERT_OBJECT_INT(entry, &processor_tbl);
|
||||
@ -190,65 +200,12 @@ proc_create_entry(u_int cpu_no, struct device_map_entry *map)
|
||||
return (entry);
|
||||
}
|
||||
|
||||
/**
|
||||
* Get the PIDs for the idle processes of the CPUs.
|
||||
*/
|
||||
static void
|
||||
processor_get_pids(void)
|
||||
{
|
||||
struct kinfo_proc *plist, *kp;
|
||||
int i;
|
||||
int nproc;
|
||||
int cpu;
|
||||
int nchars;
|
||||
struct processor_entry *entry;
|
||||
|
||||
plist = kvm_getprocs(hr_kd, KERN_PROC_ALL, 0, &nproc);
|
||||
if (plist == NULL || nproc < 0) {
|
||||
syslog(LOG_ERR, "hrProcessor: kvm_getprocs() failed: %m");
|
||||
return;
|
||||
}
|
||||
|
||||
for (i = 0, kp = plist; i < nproc; i++, kp++) {
|
||||
if (!IS_KERNPROC(kp))
|
||||
continue;
|
||||
|
||||
if (strcmp(kp->ki_comm, "idle") == 0) {
|
||||
/* single processor system */
|
||||
cpu = 0;
|
||||
} else if (sscanf(kp->ki_comm, "idle: cpu%d%n", &cpu, &nchars)
|
||||
== 1 && (u_int)nchars == strlen(kp->ki_comm)) {
|
||||
/* MP system */
|
||||
} else
|
||||
/* not an idle process */
|
||||
continue;
|
||||
|
||||
HRDBG("'%s' proc with pid %d is on CPU #%d (last on #%d)",
|
||||
kp->ki_comm, kp->ki_pid, kp->ki_oncpu, kp->ki_lastcpu);
|
||||
|
||||
TAILQ_FOREACH(entry, &processor_tbl, link)
|
||||
if (entry->cpu_no == kp->ki_lastcpu)
|
||||
break;
|
||||
|
||||
if (entry == NULL) {
|
||||
/* create entry on non-ACPI systems */
|
||||
if ((entry = proc_create_entry(cpu, NULL)) == NULL)
|
||||
continue;
|
||||
|
||||
detected_processor_count++;
|
||||
}
|
||||
|
||||
entry->idle_pid = kp->ki_pid;
|
||||
HRDBG("CPU no. %d with SNMP index=%d has idle PID %d",
|
||||
entry->cpu_no, entry->index, entry->idle_pid);
|
||||
|
||||
save_sample(entry, kp);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Scan the device map table for CPUs and create an entry into the
|
||||
* processor table for each CPU. Then fetch the idle PIDs for all CPUs.
|
||||
* processor table for each CPU.
|
||||
*
|
||||
* Make sure that the number of processors announced by the kernel hw.ncpu
|
||||
* is equal to the number of processors we have found in the device table.
|
||||
*/
|
||||
static void
|
||||
create_proc_table(void)
|
||||
@ -256,6 +213,7 @@ create_proc_table(void)
|
||||
struct device_map_entry *map;
|
||||
struct processor_entry *entry;
|
||||
int cpu_no;
|
||||
size_t len;
|
||||
|
||||
detected_processor_count = 0;
|
||||
|
||||
@ -265,7 +223,7 @@ create_proc_table(void)
|
||||
* If not, no entries will be present in the hrProcessor Table.
|
||||
*
|
||||
* For non-ACPI system the processors are not in the device table,
|
||||
* therefor insert them when getting the idle pids. XXX
|
||||
* therefore insert them after checking hw.ncpu.
|
||||
*/
|
||||
STAILQ_FOREACH(map, &device_map, link)
|
||||
if (strncmp(map->name_key, "cpu", strlen("cpu")) == 0 &&
|
||||
@ -283,9 +241,34 @@ create_proc_table(void)
|
||||
detected_processor_count++;
|
||||
}
|
||||
|
||||
HRDBG("%d CPUs detected", detected_processor_count);
|
||||
len = sizeof(hw_ncpu);
|
||||
if (sysctlbyname("hw.ncpu", &hw_ncpu, &len, NULL, 0) == -1 ||
|
||||
len != sizeof(hw_ncpu)) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: sysctl(hw.ncpu) failed");
|
||||
hw_ncpu = 0;
|
||||
}
|
||||
|
||||
HRDBG("%d CPUs detected via device table; hw.ncpu is %d",
|
||||
detected_processor_count, hw_ncpu);
|
||||
|
||||
/* XXX Can happen on non-ACPI systems? Create entries by hand. */
|
||||
for (; detected_processor_count < hw_ncpu; detected_processor_count++)
|
||||
proc_create_entry(detected_processor_count, NULL);
|
||||
|
||||
len = 2;
|
||||
if (sysctlnametomib("kern.cp_times", cpmib, &len)) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: sysctlnametomib(kern.cp_times) failed");
|
||||
cpmib[0] = 0;
|
||||
cpmib[1] = 0;
|
||||
cplen = 0;
|
||||
} else if (sysctl(cpmib, 2, NULL, &len, NULL, 0)) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: sysctl(kern.cp_times) length query failed");
|
||||
cplen = 0;
|
||||
} else {
|
||||
cplen = len / sizeof(long);
|
||||
}
|
||||
HRDBG("%zu entries for kern.cp_times", cplen);
|
||||
|
||||
processor_get_pids();
|
||||
}
|
||||
|
||||
/**
|
||||
@ -306,78 +289,6 @@ free_proc_table(void)
|
||||
detected_processor_count = 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Init the things for hrProcessorTable.
|
||||
* Scan the device table for processor entries.
|
||||
*/
|
||||
void
|
||||
init_processor_tbl(void)
|
||||
{
|
||||
size_t len;
|
||||
|
||||
/* get various parameters from the kernel */
|
||||
len = sizeof(ccpu);
|
||||
if (sysctlbyname("kern.ccpu", &ccpu, &len, NULL, 0) == -1) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: sysctl(kern.ccpu) failed");
|
||||
ccpu = 0;
|
||||
}
|
||||
|
||||
len = sizeof(fscale);
|
||||
if (sysctlbyname("kern.fscale", &fscale, &len, NULL, 0) == -1) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: sysctl(kern.fscale) failed");
|
||||
fscale = 0;
|
||||
}
|
||||
|
||||
/* create the initial processor table */
|
||||
create_proc_table();
|
||||
}
|
||||
|
||||
/**
|
||||
* Finalization routine for hrProcessorTable.
|
||||
* It destroys the lists and frees any allocated heap memory.
|
||||
*/
|
||||
void
|
||||
fini_processor_tbl(void)
|
||||
{
|
||||
|
||||
if (cpus_load_timer != NULL) {
|
||||
timer_stop(cpus_load_timer);
|
||||
cpus_load_timer = NULL;
|
||||
}
|
||||
|
||||
free_proc_table();
|
||||
}
|
||||
|
||||
/**
|
||||
* Make sure that the number of processors announced by the kernel hw.ncpu
|
||||
* is equal to the number of processors we have found in the device table.
|
||||
* If they differ rescan the device table.
|
||||
*/
|
||||
static void
|
||||
processor_refill_tbl(void)
|
||||
{
|
||||
|
||||
HRDBG("hw_ncpu=%d detected_processor_count=%d", hw_ncpu,
|
||||
detected_processor_count);
|
||||
|
||||
if (hw_ncpu <= 0) {
|
||||
size_t size = sizeof(hw_ncpu);
|
||||
|
||||
if (sysctlbyname("hw.ncpu", &hw_ncpu, &size, NULL, 0) == -1 ||
|
||||
size != sizeof(hw_ncpu)) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: "
|
||||
"sysctl(hw.ncpu) failed: %m");
|
||||
hw_ncpu = 0;
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
if (hw_ncpu != detected_processor_count) {
|
||||
free_proc_table();
|
||||
create_proc_table();
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Refresh all values in the processor table. We call this once for
|
||||
* every PDU that accesses the table.
|
||||
@ -386,37 +297,23 @@ static void
|
||||
refresh_processor_tbl(void)
|
||||
{
|
||||
struct processor_entry *entry;
|
||||
int need_pids;
|
||||
struct kinfo_proc *plist;
|
||||
int nproc;
|
||||
size_t size;
|
||||
|
||||
processor_refill_tbl();
|
||||
long pcpu_cp_times[cplen];
|
||||
memset(pcpu_cp_times, 0, sizeof(pcpu_cp_times));
|
||||
|
||||
need_pids = 0;
|
||||
TAILQ_FOREACH(entry, &processor_tbl, link) {
|
||||
if (entry->idle_pid <= 0) {
|
||||
need_pids = 1;
|
||||
continue;
|
||||
}
|
||||
|
||||
assert(hr_kd != NULL);
|
||||
|
||||
plist = kvm_getprocs(hr_kd, KERN_PROC_PID,
|
||||
entry->idle_pid, &nproc);
|
||||
if (plist == NULL || nproc != 1) {
|
||||
syslog(LOG_ERR, "%s: missing item with "
|
||||
"PID = %d for CPU #%d\n ", __func__,
|
||||
entry->idle_pid, entry->cpu_no);
|
||||
need_pids = 1;
|
||||
continue;
|
||||
}
|
||||
save_sample(entry, plist);
|
||||
size = cplen * sizeof(long);
|
||||
if (sysctl(cpmib, 2, pcpu_cp_times, &size, NULL, 0) == -1 &&
|
||||
!(errno == ENOMEM && size >= cplen * sizeof(long))) {
|
||||
syslog(LOG_ERR, "hrProcessorTable: sysctl(kern.cp_times) failed");
|
||||
return;
|
||||
}
|
||||
|
||||
if (need_pids == 1)
|
||||
processor_get_pids();
|
||||
TAILQ_FOREACH(entry, &processor_tbl, link) {
|
||||
assert(hr_kd != NULL);
|
||||
save_sample(entry, &pcpu_cp_times[entry->cpu_no * CPUSTATES]);
|
||||
}
|
||||
|
||||
proctbl_tick = this_tick;
|
||||
}
|
||||
|
||||
/**
|
||||
@ -450,6 +347,36 @@ start_processor_tbl(struct lmodule *mod)
|
||||
get_cpus_samples, NULL, mod);
|
||||
}
|
||||
|
||||
/**
|
||||
* Init the things for hrProcessorTable.
|
||||
* Scan the device table for processor entries.
|
||||
*/
|
||||
void
|
||||
init_processor_tbl(void)
|
||||
{
|
||||
|
||||
/* create the initial processor table */
|
||||
create_proc_table();
|
||||
/* and get first samples */
|
||||
refresh_processor_tbl();
|
||||
}
|
||||
|
||||
/**
|
||||
* Finalization routine for hrProcessorTable.
|
||||
* It destroys the lists and frees any allocated heap memory.
|
||||
*/
|
||||
void
|
||||
fini_processor_tbl(void)
|
||||
{
|
||||
|
||||
if (cpus_load_timer != NULL) {
|
||||
timer_stop(cpus_load_timer);
|
||||
cpus_load_timer = NULL;
|
||||
}
|
||||
|
||||
free_proc_table();
|
||||
}
|
||||
|
||||
/**
|
||||
* Access routine for the processor table.
|
||||
*/
|
||||
@ -460,9 +387,6 @@ op_hrProcessorTable(struct snmp_context *ctx __unused,
|
||||
{
|
||||
struct processor_entry *entry;
|
||||
|
||||
if (this_tick != proctbl_tick)
|
||||
refresh_processor_tbl();
|
||||
|
||||
switch (curr_op) {
|
||||
|
||||
case SNMP_OP_GETNEXT:
|
||||
|
||||
Loading…
Reference in New Issue
Block a user