KResourceLimit: Difference between revisions

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@@ Line 103: / Line 103: @@
 |-
 | 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
-| CPU time available in ticks
+| Max CPU time in ticks for preemption type 0 (default preemption type)
 |-
-| 0x64
+| 0x4
 | u32
-| Unknown
+| Current timer (in watchdog timer ticks)
 |-
-| 0x68
+| 0x8
 | u32
-| Unknown
+| Last remembered watchdog timer counter value
 |-
-| 0x6C
+| 0xC
 | 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.
-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]].
+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.