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Line 103:
Line 103: + + + + + + + + + + + + + + + − + − + − + − + − + − + − + − + + − There are 4 KResourceLimit objects created on the kernel heap. Each is used for a different category specified by the exheader's resource limit category specifier in the exheader [[NCCH/Extended_Header#ARM11_Local_System_Capabilities|ARM11 Local System Capabilities]].+ + + + +
no edit summary
|-
|-
| 0x60
| 0x60
| KPreemptionTimer
| Preemption timer for the current core, see below
|}
There are 4 KResourceLimit objects created on the kernel heap. Each is used for a different category specified by the exheader's resource limit category specifier in the exheader [[NCCH/Extended_Header#ARM11_Local_System_Capabilities|ARM11 Local System Capabilities]].
'''KPreemptionTimer''':
{| class="wikitable" border="1"
|-
! Offset
! Type
! Description
|-
| 0x0
| u32
| u32
| Unknown
| Max CPU time in ticks for preemption type 0 (default preemption type)
|-
|-
| 0x64
| 0x4
| u32
| u32
| Unknown
| Current timer (in watchdog timer ticks)
|-
|-
| 0x68
| 0x8
| u32
| u32
| Unknown
| Last remembered watchdog timer counter value
|-
|-
| 0x6C
| 0xC
| u32
| u32
| Unknown
| Max CPU time in ticks for preemption type 1
|}
|}
A call to svcSetResourceLimitValues with a limit value of 1000 for CPU time must be done first to set up some global variables and the associated [[KTimeableInterruptEvent]] instances, and another call needs to be made to actually enable preemption.
Preemption type 0: this is the default, preempts threads on core1 and allow them to run only 2ms * (timeLimit / 100).
Preemption type 1: ''seems'' to be borked, it was apparently intended to preempt threads on all cores but seems to only preempt the kernel thread running the preemptor itself and threads on core1... (time slice: 12.5ms * (timeLimit / 100))
"Firm" dev consoles can switch between these two types using svcKernelSetState type 6.