System Calls p_online(2)
NAME
p_online - return or change processor operational status
SYNOPSIS
#include
#include
int p_online(processorid_t processorid, int flag);
DESCRIPTION
The p_online() function changes or returns the operational
status of processors. The state of the processor specified by the processorid argument is changed to the state represented by the flag argument.Legal values for flag are P_STATUS, P_ONLINE, P_OFFLINE,
P_NOINTR, P_FAULTED, P_SPARE, and P_FORCED.
When flag is P_STATUS, no processor status change occurs,
but the current processor status is returned.The P_ONLINE, P_OFFLINE, P_NOINTR, P_FAULTED, and P_SPARE
values for flag refer to valid processor states. TheP_OFFLINE, P_SPARE, and P_FAULTED processor states can be
combined with the P_FORCED flag.
A processor in the P_ONLINE state is allowed to process LWPs
(lightweight processes) and perform system activities. Theprocessor is also interruptible by I/O devices attached to the system.
A processor in the P_OFFLINE state is not allowed to process
LWPs. The processor is as inactive as possible. If the hardware supports such a feature, the processor is notinterruptible by attached I/O devices.
A processor in the P_NOINTR state is allowed to process
LWPs, but it is not interruptible by attached I/O devices. Typically, interrupts, when they occur are routed to other processors in the system. Not all systems support putting a
processor into the P_NOINTR state. It is not permitted to
put all the processors of a system into the P_NOINTR state.
At least one processor must always be available to service system clock interrupts.SunOS 5.11 Last change: 11 Jan 2009 1
System Calls p_online(2)
A processor in the P_SPARE state is not allowed to process
LWPs. In many respects the P_SPARE state is similiar to the
P_OFFLINE state, but describes a processor that is available
for reactivation by management tools without administrator intervention.A processor in the P_FAULTED state is not allowed to process
LWPs. In many respects the P_FAULTED state is similiar to
the P_OFFLINE state, but describes a processor that has been
diagnosed as faulty. The privileged caller can change thestate of the processor from P_FAULTED to any of the other
states, but since the processor might generate additional errors, electing to reactivate such a processor should be carefully considered. Forced processor state transition can be requested if a newprocessor state is specified with the bitwise-inclusive OR
of the special P_FORCED flag. Forcing transition of a pro-
cessor to the P_OFFLINE, P_SPARE, or P_FAULTED state revokes
processor bindings for all threads that were previouslybound to that processor with processor_bind(2). There is no
guarantee that a forced processor state transition always succeeds. Processor numbers are integers, greater than or equal to 0, and are defined by the hardware platform. Processor numbersare not necessarily contiguous, but "not too sparse." Pro-
cessor numbers should always be printed in decimal. The maximum possible processorid value can be determined bycalling sysconf(_SC_CPUID_MAX). The list of valid processor
numbers can be determined by calling p_online() with proces-
sorid values from 0 to the maximum returned bysysconf(_SC_CPUID_MAX). The EINVAL error is returned for
invalid processor numbers. See EXAMPLES below.
RETURN VALUES
On successful completion, the value returned is the previousstate of the processor, P_ONLINE, P_OFFLINE, P_NOINTR,
P_FAULTED, P_SPARE, or P_POWEROFF. Otherwise, -1 is
returned, the CPU state remains unchanged, and errno is set to indicate the error.ERRORS
The p_online() function will fail if:
EBUSY The flag was P_OFFLINE or P_SPARE and the speci-
fied processor is the only on-line processor,
SunOS 5.11 Last change: 11 Jan 2009 2
System Calls p_online(2)
there are currently LWPs bound to the processor, or the processor performs some essential function that cannot be performed by another processor.The flag was P_NOINTR and the specified processor
is the only interruptible processor in the sys-
tem, or it handles interrupts that cannot be han-
dled by another processor. The specified processor is powered off and cannotbe powered on because some platform- specific
resource is not available.EINVAL A non-existent processor ID was specified or
flag was invalid.The caller is in a non-global zone, the pools
facility is active, and the processor is not a member of the zone's pool's processor set. ENOTSUP The specified processor is powered off, and the platform does not support power on of individual processors.EPERM The flag was not P_STATUS and the
{PRIV_SYS_RES_CONFIG} privilege is not asserted
in the effective set of the calling process.EXAMPLES
Example 1 List the legal processor numbers. The following code sample will list the legal processor numbers:#include
#include
#include
#include
#include
#include
int main() {processorid_t i, cpuid_max;
cpuid_max = sysconf(_SC_CPUID_MAX);
SunOS 5.11 Last change: 11 Jan 2009 3
System Calls p_online(2)
for (i = 0; i <= cpuid_max; i++) {
if (p_online(i, P_STATUS) != -1)
printf("processor %d present\n", i);
} return (0); }ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT-Level | MT-Safe |
|_____________________________|_____________________________|
SEE ALSO
pooladm(1M), psradm(1M), psrinfo(1M), zoneadm(1M),processor_bind(2), processor_info(2), pset_create(2),
sysconf(3C), attributes(5), privileges(5)SunOS 5.11 Last change: 11 Jan 2009 4