Xenomai
3.0-rc7
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Cobalt/POSIX scheduling management services. More...
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Functions | |
int | pthread_setschedparam (pthread_t thread, int policy, const struct sched_param *param) |
Set the scheduling policy and parameters of the specified thread. More... | |
int | pthread_setschedparam_ex (pthread_t thread, int policy, const struct sched_param_ex *param_ex) |
Set extended scheduling policy of thread. More... | |
int | pthread_getschedparam (pthread_t thread, int *__restrict__ policy, struct sched_param *__restrict__ param) |
Get the scheduling policy and parameters of the specified thread. More... | |
int | pthread_getschedparam_ex (pthread_t thread, int *__restrict__ policy_r, struct sched_param_ex *__restrict__ param_ex) |
Get extended scheduling policy of thread. More... | |
int | sched_yield (void) |
Yield the processor. More... | |
int | sched_get_priority_min (int policy) |
Get minimum priority of the specified scheduling policy. More... | |
int | sched_get_priority_min_ex (int policy) |
Get extended minimum priority of the specified scheduling policy. More... | |
int | sched_get_priority_max (int policy) |
Get maximum priority of the specified scheduling policy. More... | |
int | sched_get_priority_max_ex (int policy) |
Get extended maximum priority of the specified scheduling policy. More... | |
int | pthread_yield (void) |
Yield the processor. More... | |
int | sched_setconfig_np (int cpu, int policy, const union sched_config *config, size_t len) |
Set CPU-specific scheduler settings for a policy. More... | |
ssize_t | sched_getconfig_np (int cpu, int policy, union sched_config *config, size_t *len_r) |
Retrieve CPU-specific scheduler settings for a policy. More... | |
Cobalt/POSIX scheduling management services.
int pthread_getschedparam | ( | pthread_t | thread, |
int *__restrict__ | policy, | ||
struct sched_param *__restrict__ | param | ||
) |
Get the scheduling policy and parameters of the specified thread.
This service returns, at the addresses pol and par, the current scheduling policy and scheduling parameters (i.e. priority) of the Xenomai POSIX skin thread tid. If this service is called from user-space and tid is not the identifier of a Xenomai POSIX skin thread, this service fallback to Linux regular pthread_getschedparam service.
thread | target thread; |
policy | address where the scheduling policy of tid is stored on success; |
param | address where the scheduling parameters of tid is stored on success. |
References pthread_getschedparam_ex().
Referenced by pthread_getschedparam_ex().
int pthread_getschedparam_ex | ( | pthread_t | thread, |
int *__restrict__ | policy_r, | ||
struct sched_param_ex *__restrict__ | param_ex | ||
) |
Get extended scheduling policy of thread.
This service is an extended version of the regular pthread_getschedparam() service, which also supports Xenomai-specific or additional POSIX scheduling policies, not available with the host Linux environment.
thread | target thread; |
policy_r | address where the scheduling policy of thread is stored on success; |
param_ex | address where the scheduling parameters of thread are stored on success. |
References pthread_getschedparam().
Referenced by pthread_getschedparam().
int pthread_setschedparam | ( | pthread_t | thread, |
int | policy, | ||
const struct sched_param * | param | ||
) |
Set the scheduling policy and parameters of the specified thread.
This service set the scheduling policy of the Xenomai POSIX skin thread tid to the value pol, and its scheduling parameters (i.e. its priority) to the value pointed to by par.
When used in user-space, passing the current thread ID as tid argument, this service turns the current thread into a Xenomai POSIX skin thread. If tid is neither the identifier of the current thread nor the identifier of a Xenomai POSIX skin thread this service falls back to the regular pthread_setschedparam() service, hereby causing the current thread to switch to secondary mode if it is Xenomai thread.
thread | target thread; |
policy | scheduling policy, one of SCHED_FIFO, SCHED_RR, SCHED_SPORADIC, SCHED_TP or SCHED_OTHER; |
param | scheduling parameters address. |
When creating or shadowing a Xenomai thread for the first time in user-space, Xenomai installs a handler for the SIGSHADOW signal. If you had installed a handler before that, it will be automatically called by Xenomai for SIGSHADOW signals that it has not sent.
If, however, you install a signal handler for SIGSHADOW after creating or shadowing the first Xenomai thread, you have to explicitly call the function xeno_sigwinch_handler at the beginning of your signal handler, using its return to know if the signal was in fact an internal signal of Xenomai (in which case it returns 1), or if you should handle the signal (in which case it returns 0). xeno_sigwinch_handler prototype is:
int xeno_sigwinch_handler(int sig, siginfo_t *si, void *ctxt);
Which means that you should register your handler with sigaction, using the SA_SIGINFO flag, and pass all the arguments you received to xeno_sigwinch_handler.
References pthread_setschedparam_ex().
int pthread_setschedparam_ex | ( | pthread_t | thread, |
int | policy, | ||
const struct sched_param_ex * | param_ex | ||
) |
Set extended scheduling policy of thread.
This service is an extended version of the regular pthread_setschedparam() service, which supports Xenomai-specific or additional scheduling policies, not available with the host Linux environment.
This service set the scheduling policy of the Xenomai thread thread to the value policy, and its scheduling parameters (e.g. its priority) to the value pointed to by param_ex.
If thread does not match the identifier of a Xenomai thread, this action falls back to the regular pthread_setschedparam() service.
thread | target Cobalt thread; |
policy | scheduling policy, one of SCHED_WEAK, SCHED_FIFO, SCHED_COBALT, SCHED_RR, SCHED_SPORADIC, SCHED_TP, SCHED_QUOTA or SCHED_NORMAL; |
param_ex | scheduling parameters address. As a special exception, a negative sched_priority value is interpreted as if SCHED_WEAK was given in policy, using the absolute value of this parameter as the weak priority level. |
When CONFIG_XENO_OPT_SCHED_WEAK is enabled, SCHED_WEAK exhibits priority levels in the [0..99] range (inclusive). Otherwise, sched_priority must be zero for the SCHED_WEAK policy.
When creating or shadowing a Xenomai thread for the first time in user-space, Xenomai installs a handler for the SIGSHADOW signal. If you had installed a handler before that, it will be automatically called by Xenomai for SIGSHADOW signals that it has not sent.
If, however, you install a signal handler for SIGSHADOW after creating or shadowing the first Xenomai thread, you have to explicitly call the function cobalt_sigshadow_handler at the beginning of your signal handler, using its return to know if the signal was in fact an internal signal of Xenomai (in which case it returns 1), or if you should handle the signal (in which case it returns 0). cobalt_sigshadow_handler prototype is:
int cobalt_sigshadow_handler(int sig, struct siginfo *si, void *ctxt);
Which means that you should register your handler with sigaction, using the SA_SIGINFO flag, and pass all the arguments you received to cobalt_sigshadow_handler.
pthread_setschedparam_ex() may switch the caller to secondary mode.
Referenced by pthread_setschedparam().
int pthread_yield | ( | void | ) |
Yield the processor.
This function move the current thread at the end of its priority group.
0 |
References sched_yield().
int sched_get_priority_max | ( | int | policy | ) |
Get maximum priority of the specified scheduling policy.
This service returns the maximum priority of the scheduling policy policy.
policy | scheduling policy. |
0 | on success; |
-1 | with errno set if:
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Referenced by sched_get_priority_max_ex().
int sched_get_priority_max_ex | ( | int | policy | ) |
Get extended maximum priority of the specified scheduling policy.
This service returns the maximum priority of the scheduling policy policy, reflecting any Cobalt extension to standard classes.
policy | scheduling policy. |
0 | on success; |
-1 | with errno set if:
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References sched_get_priority_max().
int sched_get_priority_min | ( | int | policy | ) |
Get minimum priority of the specified scheduling policy.
This service returns the minimum priority of the scheduling policy policy.
policy | scheduling policy. |
0 | on success; |
-1 | with errno set if:
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Referenced by sched_get_priority_min_ex().
int sched_get_priority_min_ex | ( | int | policy | ) |
Get extended minimum priority of the specified scheduling policy.
This service returns the minimum priority of the scheduling policy policy, reflecting any Cobalt extension to the standard classes.
policy | scheduling policy. |
0 | on success; |
-1 | with errno set if:
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References sched_get_priority_min().
ssize_t sched_getconfig_np | ( | int | cpu, |
int | policy, | ||
union sched_config * | config, | ||
size_t * | len_r | ||
) |
Retrieve CPU-specific scheduler settings for a policy.
A configuration is strictly local to the target cpu, and may differ from other processors.
cpu | processor to retrieve the configuration of. |
policy | scheduling policy to which the configuration data applies. Currently, only SCHED_TP and SCHED_QUOTA are valid input. |
config | a pointer to a memory area which receives the configuration settings upon success of this call. |
On successful return, config->quota.tp contains the TP schedule active on cpu.
On entry, config->quota.get.tgid must contain the thread group identifier to inquire about.
On successful exit, config->quota.info contains the information related to the thread group referenced to by config->quota.get.tgid.
[in,out] | len_r | a pointer to a variable for collecting the overall length of the configuration data returned (in bytes). This variable must contain the amount of space available in config when the request is issued. |
int sched_setconfig_np | ( | int | cpu, |
int | policy, | ||
const union sched_config * | config, | ||
size_t | len | ||
) |
Set CPU-specific scheduler settings for a policy.
A configuration is strictly local to the target cpu, and may differ from other processors.
cpu | processor to load the configuration of. |
policy | scheduling policy to which the configuration data applies. Currently, SCHED_TP and SCHED_QUOTA are valid. |
config | a pointer to the configuration data to load on cpu, applicable to policy. |
This call controls the temporal partitions for cpu, depending on the operation requested.
Time slots must be strictly contiguous, i.e. windows[n].offset + windows[n].duration shall equal windows[n + 1].offset. If windows[].ptid is in the range [0..CONFIG_XENO_OPT_SCHED_TP_NRPART-1], SCHED_TP threads which belong to the partition being referred to may be given CPU time on cpu, from time windows[].offset to windows[].offset + windows[].duration, provided those threads are in a runnable state.
Time holes between valid time slots may be defined using windows activating the pseudo partition -1. When such window is active in the global time frame, no CPU time is available to SCHED_TP threads on cpu.
This call manages thread groups running on cpu, defining per-group quota for limiting their CPU consumption.
All three operations fill in the config.info structure with the information reflecting the state of the scheduler on cpu with respect to policy, after the requested changes have been applied.
len | overall length of the configuration data (in bytes). |
int sched_yield | ( | void | ) |
Yield the processor.
This function move the current thread at the end of its priority group.
0 |
References XNRELAX, and XNWEAK.
Referenced by pthread_yield().