cap_util.c revision b885580b43755ee4ea1e280b85428893d2ba9291
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
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*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Support for determining capacity and utilization of performance relevant
* hardware components in a computer
*
* THEORY
* ------
* The capacity and utilization of the performance relevant hardware components
* is needed to be able to optimize performance while minimizing the amount of
* power used on a system. The idea is to use hardware performance counters
* and potentially other means to determine the capacity and utilization of
* performance relevant hardware components (eg. execution pipeline, cache,
* memory, etc.) and attribute the utilization to the responsible CPU and the
* thread running there.
*
* This will help characterize the utilization of performance relevant
* components and how much is used by each CPU and each thread. With
* that data, the utilization can be aggregated to all the CPUs sharing each
* performance relevant hardware component to calculate the total utilization
* of each component and compare that with the component's capacity to
* essentially determine the actual hardware load of the component. The
* hardware utilization attributed to each running thread can also be
* aggregated to determine the total hardware utilization of each component to
* a workload.
*
* Once that is done, one can determine how much of each performance relevant
* hardware component is needed by a given thread or set of threads (eg. a
* workload) and size up exactly what hardware is needed by the threads and how
* much. With this info, we can better place threads among CPUs to match their
* exact hardware resource needs and potentially lower or raise the power based
* on their utilization or pack threads onto the fewest hardware components
* needed and power off any remaining unused components to minimize power
* without sacrificing performance.
*
* IMPLEMENTATION
* --------------
* The code has been designed and implemented to make (un)programming and
* reading the counters for a given CPU as lightweight and fast as possible.
* This is very important because we need to read and potentially (un)program
* the counters very often and in performance sensitive code. Specifically,
* cyclic handler when there are more counter events to count than existing
* counters.
*
* Consequently, the code has been split up to allow allocating and
* initializing everything needed to program and read the counters on a given
* CPU once and make (un)programming and reading the counters for a given CPU
* state needed to (un)program and read the counters on a CPU is kept per CPU
* and is made lock free by forcing any code that reads or manipulates the
* counters or the state needed to (un)program or read the counters to run on
* the target CPU and disable preemption while running on the target CPU to
* protect any critical sections. All counter manipulation on the target CPU is
* happening either from a cross-call to the target CPU or at the same PIL as
* used by the cross-call subsystem. This guarantees that counter manipulation
* is not interrupted by cross-calls from other CPUs.
*
* The synchronization has been made lock free or as simple as possible for
* performance and to avoid getting the locking all tangled up when we interpose
* on the CPC routines that (un)program the counters to manage the counters
* between the kernel and user on each CPU. When the user starts using the
* counters on a given CPU, the kernel will unprogram the counters that it is
* using on that CPU just before they are programmed for the user. Then the
* kernel will program the counters on a given CPU for its own use when the user
* stops using them.
*
* There is a special interaction with DTrace cpc provider (dcpc). Before dcpc
* enables any probe, it requests to disable and unprogram all counters used for
* capacity and utilizations. These counters are never re-programmed back until
* dcpc completes. When all DTrace cpc probes are removed, dcpc notifies CU
* framework and it re-programs the counters.
*
* When a CPU is going offline, its CU counters are unprogrammed and disabled,
* so that they would not be re-programmed again by some other activity on the
* CPU that is going offline.
*
* The counters are programmed during boot. However, a flag is available to
* disable this if necessary (see cu_flag below). A handler is provided to
* to initialize and tear down this module, initialize and tear down any state
* needed for a given CPU, and (un)program the counters for a given CPU.
* Lastly, a handler is provided to read the counters and attribute the
* utilization to the responsible CPU.
*/
#include <sys/cap_util.h>
#include <sys/archsystm.h>
#if defined(__x86)
#include <sys/xc_levels.h>
#endif
/*
* Default CPU hardware performance counter flags to use for measuring capacity
* and utilization
*/
#define CU_CPC_FLAGS_DEFAULT \
/*
* Possible Flags for controlling this module.
*/
/*
* pg_cpu kstats calculate utilization rate and maximum utilization rate for
* some CPUs. The rate is calculated based on data from two subsequent
* snapshots. When the time between such two snapshots is too small, the
* resulting rate may have low accuracy, so we only consider snapshots which
* are separated by SAMPLE_INTERVAL nanoseconds from one another. We do not
* update the rate if the interval is smaller than that.
*
* Use one tenth of a second as the minimum interval for utilization rate
* calculation.
*
* NOTE: The CU_SAMPLE_INTERVAL_MIN should be higher than the scaling factor in
* the CU_RATE() macro below to guarantee that we never divide by zero.
*
* Rate is the number of events per second. The rate is the number of events
* divided by time and multiplied by the number of nanoseconds in a second. We
* do not want time to be too small since it will cause large errors in
* division.
*
* We do not want to multiply two large numbers (the instruction count and
* NANOSEC) either since it may cause integer overflow. So we divide both the
* numerator and the denominator by the same value.
*
* NOTE: The scaling factor below should be less than CU_SAMPLE_INTERVAL_MIN
* above to guarantee that time divided by this value is always non-zero.
*/
/*
* When the time between two kstat reads for the same CPU is less than
* CU_UPDATE_THRESHOLD use the old counter data and skip updating counter values
* for the CPU. This helps reduce cross-calls when kstat consumers read data
* very often or when they read PG utilization data and then CPU utilization
* data quickly after that.
*/
/*
* The IS_HIPIL() macro verifies that the code is executed either from a
* cross-call or from high-PIL interrupt
*/
#ifdef DEBUG
#else
#define IS_HIPIL()
#endif /* DEBUG */
typedef void (*cu_cpu_func_t)(uintptr_t, int *);
/*
* Flags to use for programming CPU hardware performance counters to measure
* capacity and utilization
*/
int cu_cpc_flags = CU_CPC_FLAGS_DEFAULT;
/*
* Initial value used for programming hardware counters
*/
/*
* List of CPC event requests for capacity and utilization.
*/
/*
* When a CPU is a member of PG with a sharing relationship that is supported
* by the capacity/utilization framework, a kstat is created for that CPU and
* sharing relationship.
*
* These kstats are updated one at a time, so we can have a single scratch
* space to fill the data.
*
* CPU counter kstats fields:
*
* cu_cpu_id CPU ID for this kstat
*
* cu_generation Generation value that increases whenever any CPU goes
* offline or online. Two kstat snapshots for the same
* CPU may only be compared if they have the same
* generation.
*
* cu_pg_id PG ID for the relationship described by this kstat
*
* cu_cpu_util Running value of CPU utilization for the sharing
* relationship
*
* cu_cpu_time_running Total time spent collecting CU data. The time may be
* less than wall time if CU counters were stopped for
* some time.
*
* cu_cpu_time_stopped Total time the CU counters were stopped.
*
* cu_cpu_rate Utilization rate, expressed in operations per second.
*
* cu_cpu_rate_max Maximum observed value of utilization rate.
*/
struct cu_cpu_kstat {
} cu_cpu_kstat = {
{ "id", KSTAT_DATA_UINT32 },
{ "generation", KSTAT_DATA_UINT32 },
{ "pg_id", KSTAT_DATA_LONG },
{ "hw_util", KSTAT_DATA_UINT64 },
{ "hw_util_time_running", KSTAT_DATA_UINT64 },
{ "hw_util_time_stopped", KSTAT_DATA_UINT64 },
{ "hw_util_rate", KSTAT_DATA_UINT64 },
{ "hw_util_rate_max", KSTAT_DATA_UINT64 },
};
/*
* Flags for controlling this module
*/
/*
* Error return value for cu_init() since it can't return anything to be called
* from mp_init_tbl[] (:-(
*/
static int cu_init_error = 0;
static kmutex_t pg_cpu_kstat_lock;
/*
* Forward declaration of interface routines
*/
void cu_disable(void);
void cu_enable(void);
void cu_init(void);
/*
* Forward declaration of private routines
*/
static void cu_cpu_info_detach_xcall(void);
/*
* Disable or enable Capacity Utilization counters on all CPUs.
*/
void
cu_disable(void)
{
cp = cpu_active;
do {
}
void
cu_enable(void)
{
cp = cpu_active;
do {
}
/*
* Setup capacity and utilization support
*/
void
cu_init(void)
{
cu_init_error = 0;
cu_init_error = -1;
return;
}
if (kcpc_init() != 0) {
cu_init_error = -2;
return;
}
/*
* Can't measure hardware capacity and utilization without CPU
* hardware performance counters
*/
if (cpc_ncounters <= 0) {
cu_init_error = -3;
return;
}
/*
* Setup CPC event request queue
*/
/*
* Mark flags to say that module is ready to be setup
*/
cp = cpu_active;
do {
/*
* Allocate and setup state needed to measure capacity and
* utilization
*/
cu_init_error = -5;
/*
* Reset list of counter event requests so its space can be
* reused for a different set of requests for next CPU
*/
(void) kcpc_reqs_reset(cu_cpc_reqs);
} while (cp != cpu_active);
/*
* Mark flags to say that module is on now and counters are ready to be
* programmed on all active CPUs
*/
cu_flags |= CU_FLAG_ON;
/*
* Program counters on currently active CPUs
*/
cp = cpu_active;
do {
cu_init_error = -6;
} while (cp != cpu_active);
/*
* Register callback for CPU state changes to enable and disable
* CPC counters as CPUs come on and offline
*/
}
/*
* Return number of counter events needed to measure capacity and utilization
* for specified CPU and fill in list of CPC requests with each counter event
* needed if list where to add CPC requests is given
*
* NOTE: Use KM_NOSLEEP for kmem_{,z}alloc() since cpu_lock is held and free
* everything that has been successfully allocated if any memory
* allocation fails
*/
static int
{
int nevents;
/*
* There has to be a target CPU for this
*/
return (-1);
/*
* Return 0 when CPU doesn't belong to any group
*/
return (0);
/*
* Grab counter statistics and info
*/
} else {
return (-2);
}
/*
* See whether platform (or processor) specific code knows which CPC
* events to request, etc. are needed to measure hardware capacity and
* utilization on this machine
*/
if (nevents >= 0)
return (nevents);
/*
* Let common code decide which CPC events to request, etc. to measure
* capacity and utilization since platform (or processor) specific does
* not know....
*
* Walk CPU's PG lineage and do following:
*
* - Setup CPC request, counter info, and stats needed for each counter
* event to measure capacity and and utilization for each of CPU's PG
* hardware sharing relationships
*
* - Create PG CPU kstats to export capacity and utilization for each PG
*/
nevents = 0;
int nevents_save;
int nstats;
nstats = 0;
switch (pg_hw_type) {
case PGHW_IPIPE:
KM_NOSLEEP, &nevents) != 0)
continue;
nstats = 1;
break;
case PGHW_FPU:
KM_NOSLEEP, &nevents) != 0)
continue;
nstats = 1;
break;
default:
/*
* Don't measure capacity and utilization for this kind
* of PG hardware relationship so skip to next PG in
* CPU's PG lineage
*/
continue;
}
/*
* Nothing to measure for this hardware sharing relationship
*/
if (nevents - nevents_save == 0) {
continue;
}
/*
* Fill in counter info for this PG hardware relationship
*/
continue;
}
/*
* Create PG CPU kstats for this hardware relationship
*/
}
return (nevents);
}
/*
* Program counters for capacity and utilization on given CPU
*
* If any of the following conditions is true, the counters are not programmed:
*
* - CU framework is disabled
* - The cpu_cu_info field of the cpu structure is NULL
* - DTrace is active
* - Counters are programmed already
* - Counters are disabled (by calls to cu_cpu_disable())
*/
void
{
/*
* Should be running on given CPU. We disable preemption to keep CPU
* from disappearing and make sure flags and CPC context don't change
* from underneath us
*/
/*
* Module not ready to program counters
*/
if (!(cu_flags & CU_FLAG_ON)) {
*err = -1;
return;
}
*err = -2;
return;
}
if (cu_cpu_info == NULL) {
*err = -3;
return;
}
/*
* If DTrace CPC is active or counters turned on already or are
* disabled, just return.
*/
*err = 1;
return;
}
*err = -4;
return;
}
/*
* Get CPU's CPC context needed for capacity and utilization
*/
cpu_ctx->ctx_ptr_array_sz <= 0) {
*err = -5;
return;
}
/*
* Increment index in CPU's CPC context info to point at next context
* to program
*
* NOTE: Do this now instead of after programming counters to ensure
* that index will always point at *current* context so we will
* always be able to unprogram *current* context if necessary
*/
/*
* Clear KCPC_CTX_INVALID and KCPC_CTX_INVALID_STOPPED from CPU's CPC
* context before programming counters
*
* Context is marked with KCPC_CTX_INVALID_STOPPED when context is
* unprogrammed and may be marked with KCPC_CTX_INVALID when
* kcpc_invalidate_all() is called by cpustat(1M) and dtrace CPC to
* invalidate all CPC contexts before they take over all the counters.
*
* This isn't necessary since these flags are only used for thread bound
* CPC contexts not CPU bound CPC contexts like ones used for capacity
* and utilization.
*
* There is no need to protect the flag update since no one is using
* this context now.
*/
/*
* Program counters on this CPU
*/
/*
* Set state in CPU structure to say that CPU's counters are programmed
* for capacity and utilization now and that they are transitioning from
* off to on state. This will cause cu_cpu_update to update stop times
* for all programmed counters.
*/
/*
* Update counter statistics
*/
*err = 0;
}
/*
* Cross call wrapper routine for cu_cpc_program()
*
* Checks to make sure that counters on CPU aren't being used by someone else
* before calling cu_cpc_program() since cu_cpc_program() needs to assert that
* nobody else is using the counters to catch and prevent any broken code.
* Also, this check needs to happen on the target CPU since the CPU's CPC
* context can only be changed while running on the CPU.
*
* If the first argument is TRUE, cu_cpc_program_xcall also checks that there is
* no valid thread bound cpc context. This is important to check to prevent
* re-programming thread counters with CU counters when CPU is coming on-line.
*/
static void
{
*err = -100;
return;
}
*err = -200;
return;
}
}
/*
* Unprogram counters for capacity and utilization on given CPU
* This function should be always executed on the target CPU at high PIL
*/
void
{
/*
* Should be running on given CPU with preemption disabled to keep CPU
* from disappearing and make sure flags and CPC context don't change
* from underneath us
*/
/*
* Module not on
*/
if (!(cu_flags & CU_FLAG_ON)) {
*err = -1;
return;
}
if (cu_cpu_info == NULL) {
*err = -3;
return;
}
/*
* Counters turned off already
*/
*err = 1;
return;
}
/*
* Update counter statistics
*/
/*
* Get CPU's CPC context needed for capacity and utilization
*/
cpu_ctx->ctx_ptr_array_sz <= 0) {
*err = -5;
return;
}
/*
* CPU's CPC context should be current capacity and utilization CPC
* context
*/
*err = -6;
return;
}
/*
* Unprogram counters on CPU.
*/
/*
* Unset state in CPU structure saying that CPU's counters are
* programmed
*/
*err = 0;
}
/*
* Add given counter event to list of CPC requests
*/
static int
{
int n;
int retval;
/*
* Return error when no counter event specified, counter event not
* supported by CPC's PCBE, or number of events not given
*/
return (-1);
n = *nevents;
/*
* Only count number of counter events needed if list
* where to add CPC requests not given
*/
n++;
*nevents = n;
return (-3);
}
/*
* Return error when stats not given or not enough room on list of CPC
* requests for more counter events
*/
return (-4);
/*
* Use flags in cu_cpc_flags to program counters and enable overflow
* interrupts/traps (unless PCBE can't handle overflow interrupts) so
* PCBE can catch counters before they wrap to hopefully give us an
* accurate (64-bit) virtualized counter
*/
if ((kcpc_pcbe_capabilities() & CPC_CAP_OVERFLOW_INTERRUPT) == 0)
flags &= ~CPC_OVF_NOTIFY_EMT;
/*
* Add CPC request to list
*/
if (retval != 0)
return (-5);
n++;
*nevents = n;
return (0);
}
static void
cu_cpu_info_detach_xcall(void)
{
}
/*
* Enable or disable collection of capacity/utilization data for a current CPU.
* Counters are enabled if 'on' argument is True and disabled if it is False.
* This function should be always executed at high PIL
*/
static void
{
int error;
if (!(cu_flags & CU_FLAG_ON)) {
return;
}
if (cu_cpu_info == NULL) {
return;
}
if (on) {
/*
* Decrement the cu_disabled counter.
* Once it drops to zero, call cu_cpc_program.
*/
if (cu_cpu_info->cu_disabled > 0)
if (cu_cpu_info->cu_disabled == 0)
} else if (cu_cpu_info->cu_disabled++ == 0) {
/*
* This is the first attempt to disable CU, so turn it off
*/
}
}
/*
* Callback for changes in CPU states
* Used to enable or disable hardware performance counters on CPUs that are
* turned on or off
*
* NOTE: cpc should be programmed/unprogrammed while running on the target CPU.
* We have to use thread_affinity_set to hop to the right CPU because these
* routines expect cpu_lock held, so we can't cross-call other CPUs while
* holding CPU lock.
*/
static int
/* LINTED E_FUNC_ARG_UNUSED */
{
int retval = 0;
if (!(cu_flags & CU_FLAG_ON))
return (-1);
return (-2);
switch (what) {
case CPU_ON:
/*
* Setup counters on CPU being turned on
*/
/*
* Reset list of counter event requests so its space can be
* reused for a different set of requests for next CPU
*/
(void) kcpc_reqs_reset(cu_cpc_reqs);
break;
case CPU_INTR_ON:
/*
* Setup counters on CPU being turned on.
*/
break;
case CPU_OFF:
/*
* Disable counters on CPU being turned off. Counters will not
* be re-enabled on this CPU until it comes back online.
*/
break;
default:
break;
}
return (retval);
}
/*
* Disable or enable Capacity Utilization counters on a given CPU. This function
* can be called from any CPU to disable counters on the given CPU.
*/
static void
{
}
static void
{
}
/*
* Setup capacity and utilization support for given CPU
*
* NOTE: Use KM_NOSLEEP for kmem_{,z}alloc() since cpu_lock is held and free
* everything that has been successfully allocated including cpu_cu_info
* if any memory allocation fails
*/
static int
{
int n;
/*
* cpu_lock should be held and protect against CPU going away and races
* with cu_{init,fini,cpu_fini}()
*/
/*
* Return if not ready to setup counters yet
*/
if (!(cu_flags & CU_FLAG_READY))
return (-1);
return (-2);
}
/*
* Get capacity and utilization CPC context for CPU and check to see
* whether it has been setup already
*/
cpu_ctx->ctx_ptr_array_sz > 0) {
return (1);
}
/*
* Should have no contexts since it hasn't been setup already
*/
cpu_ctx->ctx_ptr_array_sz == 0);
/*
* Determine how many CPC events needed to measure capacity and
* utilization for this CPU, allocate space for counter statistics for
* each event, and fill in list of CPC event requests with corresponding
* counter stats for each request to make attributing counter data
* easier later....
*/
if (n <= 0) {
(void) cu_cpu_fini(cp);
return (-3);
}
(void) cu_cpu_fini(cp);
return (-4);
}
cu_cpu_info->cu_ncntr_stats = n;
if (n <= 0) {
(void) cu_cpu_fini(cp);
return (-5);
}
/*
* Create CPC context with given requests
*/
ctx_ptr_array_sz = 0;
if (n <= 0) {
(void) cu_cpu_fini(cp);
return (-6);
}
/*
* Should have contexts
*/
(void) cu_cpu_fini(cp);
return (-7);
}
/*
* Fill in CPC context info for CPU needed for capacity and utilization
*/
return (0);
}
/*
* Tear down capacity and utilization support for given CPU
*/
static int
{
int i;
/*
* cpu_lock should be held and protect against CPU going away and races
* with cu_{init,fini,cpu_init}()
*/
/*
* Have to at least be ready to setup counters to have allocated
* anything that needs to be deallocated now
*/
if (!(cu_flags & CU_FLAG_READY))
return (-1);
/*
* Nothing to do if CPU's capacity and utilization info doesn't exist
*/
if (cu_cpu_info == NULL)
return (1);
/*
* Tear down any existing kstats and counter info for each hardware
* sharing relationship
*/
pg_hw_type++) {
continue;
}
}
/*
* Free counter statistics for CPU
*/
cu_cpu_info->cu_ncntr_stats > 0);
cu_cpu_info->cu_ncntr_stats > 0) {
cu_cpu_info->cu_ncntr_stats = 0;
}
/*
* Get capacity and utilization CPC contexts for given CPU and check to
* see whether they have been freed already
*/
cpu_ctx->ctx_ptr_array_sz > 0) {
/*
* Free CPC contexts for given CPU
*/
continue;
}
/*
* Free CPC context pointer array
*/
/*
* Zero CPC info for CPU
*/
}
/*
* Set cp->cpu_cu_info pointer to NULL. Go through cross-call to ensure
* that no one is going to access the cpu_cu_info whicch we are going to
* free.
*/
if (cpu_is_online(cp))
else
/*
* Free CPU's capacity and utilization info
*/
return (0);
}
/*
* Create capacity & utilization kstats for given PG CPU hardware sharing
* relationship
*/
static void
{
/*
* Just return when no counter info or CPU
*/
return;
/*
* Get the class name from the leaf PG that this CPU belongs to.
* If there are no PGs, just use the default class "cpu".
*/
sizeof (cu_cpu_kstat) / sizeof (kstat_named_t),
return;
}
/*
* Propagate values from CPU capacity & utilization stats to kstats
*/
static int
{
if (rw == KSTAT_WRITE)
return (EACCES);
/*
* Update capacity and utilization statistics needed for CPU's PG (CPU)
* kstats
*/
else
/*
* Counters are stopped now, so the cs_time_stopped was last
* updated at cs_time_start time. Add the time passed since then
* to the stopped time.
*/
return (0);
}
/*
* Run specified function with specified argument on a given CPU and return
* whatever the function returns
*/
static int
{
int error = 0;
/*
* cpu_call() will call func on the CPU specified with given argument
* and return func's return value in last argument
*/
return (error);
}
/*
* Update counter statistics on a given CPU.
*
* If move_to argument is True, execute the function on the CPU specified
* Otherwise, assume that it is already runninng on the right CPU
*
* If move_to is specified, the caller should hold cpu_lock or have preemption
* disabled. Otherwise it is up to the caller to guarantee that things do not
* change in the process.
*/
int
{
int retval;
/*
* Nothing to do if counters are not programmed
*/
if (!(cu_flags & CU_FLAG_ON) ||
(cu_cpu_info == NULL) ||
return (0);
/*
* Don't update CPU statistics if it was updated recently
* and provide old results instead
*/
return (0);
}
/*
* CPC counter should be read on the CPU that is running the counter. We
* either have to move ourselves to the target CPU or insure that we
* already run there.
*
* We use cross-call to the target CPU to execute kcpc_read() and
* cu_cpu_update_stats() there.
*/
retval = 0;
if (move_to)
else {
/*
* Offset negative return value by -10 so we can distinguish it
* from error return values of this routine vs kcpc_read()
*/
if (retval < 0)
retval -= 10;
}
return (retval);
}
/*
* Update CPU counter statistics for current CPU.
* This function may be called from a cross-call
*/
static int
{
return (-1);
/*
* Nothing to do if counters are not programmed. This should not happen,
* but we check just in case.
*/
if (!(cu_flags & CU_FLAG_ON) ||
(cu_cpu_info == NULL))
return (-2);
if (!(flags & CU_CPU_CNTRS_ON))
return (-2);
/*
* Take snapshot of high resolution timer
*/
/*
* CU counters have just been programmed. We cannot assume that the new
* cntr_value continues from where we left off, so use the cntr_value as
* the new initial value.
*/
if (flags & CU_CPU_CNTRS_OFF_ON)
/*
* Calculate delta in counter values between start of sampling period
* and now
*/
/*
* Calculate time between start of sampling period and now
*/
0;
if (time_delta > 0) { /* wrap shouldn't happen */
/*
* Update either running or stopped time based on the transition
* state
*/
if (flags & CU_CPU_CNTRS_OFF_ON)
else
}
/*
* Update rest of counter statistics if counter value didn't wrap
*/
if (delta > 0) {
/*
* Update utilization rate if the interval between samples is
* sufficient.
*/
if (time_delta > cu_sample_interval_min)
}
return (0);
}
/*
* Update CMT PG utilization data.
*
* This routine computes the running total utilization and times for the
* specified PG by adding up the total utilization and counter running and
* stopped times of all CPUs in the PG and calculates the utilization rate and
* maximum rate for all CPUs in the PG.
*/
void
{
/*
* Initialize running total utilization and times for PG to 0
*/
hw_util->pghw_time_running = 0;
hw_util->pghw_time_stopped = 0;
/*
* Iterate over all CPUs in the PG and aggregate utilization, running
* time and stopped time.
*/
if (cu_cpu_info == NULL)
continue;
/*
* Update utilization data for the CPU and then
* aggregate per CPU running totals for PG
*/
continue;
/*
* If counters are stopped now, the pg_time_stopped was last
* updated at cs_time_start time. Add the time passed since then
* to the stopped time.
*/
}
/*
* Compute per PG instruction rate and maximum rate
*/
if (old_utilization == 0)
return;
/*
* Calculate change in utilization over sampling period and set this to
* 0 if the delta would be 0 or negative which may happen if any CPUs go
* offline during the sampling period
*/
else
utilization_delta = 0;
/*
* Update utilization rate if the interval between samples is
* sufficient.
*/
if (time_delta > CU_SAMPLE_INTERVAL_MIN)
/*
* Update the maximum observed rate
*/
}