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* Protect SCHED_LITMUS tasks from reschedules triggered by SCHED_FIFO enqueues.2012.3Jonathan Herman2012-12-21
| | | | (BB: edited to include <litmus/litmus.h> to resolve compile error.)
* Config: PREEMPT_STATE_TRACE depends on DEBUG_KERNEL.Christopher Kenna2012-12-11
| | | | | | | | | | This patch makes CONFIG_PREEMPT_STATE_TRACE depend on CONFIG_DEBUG_KERNEL. Prior to this patch, selecting PREEMPT_STATE_TRACE resulted in linker errors (see below), because sched_state_name is not built unless DEBUG_KERNEL is selected. kernel/built-in.o: In function `schedule': (.sched.text+0x3d2): undefined reference to `sched_state_name'
* Send reboot notifications to LitmusGlenn Elliott2012-12-07
| | | | | | | | This patch causes reboot notifications to be send to Litmus. With this patch, Litmus attempts to switch back to the Linux-plugin before the reboot proceeds. Any failures to switch back are reported via printk() (the reboot is not halted).
* litmus: get rid of unused RT_F_EXIT_SEM flagManohar Vanga2012-11-27
| | | | | | | | | | | | | This patch removes the RT_F_EXIT_SEM flag. All code paths depending on it being true are assumed to be unreachable and removed. The 'flags' field in struct rt_params is left as-is for use by specific schedulers. For example, sched_pfair defines a custom flag RT_F_REQUEUE within the 'flags' field. Signed-off-by: Manohar Vanga <mvanga@mpi-sws.org>
* litmus: use is_present() instead of using rt_param->presentManohar Vanga2012-11-27
| | | | Signed-off-by: Manohar Vanga <mvanga@mpi-sws.org>
* litmus: get rid of RT_F_SLEEP and RT_F_RUNNINGManohar Vanga2012-11-27
| | | | | | | | This patch removes the flags RT_F_SLEEP and RT_F_RUNNING as their name is misleading. This patch replaces them with a 'completed' field in struct rt_param. Signed-off-by: Manohar Vanga <mvanga@mpi-sws.org>
* litmus: fix warning about unused label in sched_pfp.cManohar Vanga2012-11-27
| | | | | | | This patch fixes a warning about an unused label in sched_pfp.c when CONFIG_LITMUS_LOCKING is not set. Signed-off-by: Manohar Vanga <mvanga@mpi-sws.org>
* litmus: fix compiler warning in sched_plugin.hManohar Vanga2012-11-27
| | | | | | | | This patch fixes the compiler warning about struct litmus_locking being defined in the parameter list when CONFIG_LITMUS_LOCKING is not set. Signed-off-by: Manohar Vanga <mvanga@mpi-sws.org>
* P-FP: be less permissive about non-running tasks in queueBjoern Brandenburg2012-10-18
| | | | No suspended task should ever be queued in this plugin.
* P-FP: be paranoid in the preemption caseBjoern Brandenburg2012-10-18
| | | | | Crash and burn if an expected preemption didn't happen. This is useful to flag any bugs in the queue management code...
* P-FP: use proper CONFIG_ symbolBjoern Brandenburg2012-10-18
| | | | It's CONFIG_LITMUS_LOCKING, not just CONFIG_LOCKING...
* P-FP: prevent misuse of priority queueBjoern Brandenburg2012-10-18
| | | | Stop hard-to-detect out-of-bounds errors early.
* P-FP: simplify priority comparisonBjoern Brandenburg2012-10-18
| | | | | | Make the priority comparison easier to read. Also, remove the "equal PID" clause and insert a corresponding BUG_ON() instead; this should really never happen.
* P-FP: simplify boost_priority()Bjoern Brandenburg2012-10-18
| | | | | | boost_priority() is only applied to already-scheduled tasks. Remove the (untested and unneeded) case handling unscheduled tasks, which was likely not correct anyway.
* P-FP: record job release records for tardy tasksBjoern Brandenburg2012-10-18
| | | | | When a job was tardy, the plugin failed to invoke sched_trace. This caused ugly "holes" in the visualized schedule.
* Move SEND_RESCHED tracing to preempt.cBjoern Brandenburg2012-10-18
| | | | | | | The SEND_RESCHED is really only interesting if the IPI was generated by LITMUS^RT. Therefore, we don't need to trace in Linux's architecture-specific code. Instead, we hook into the preemption state machine, which is informed about incoming IPIs anyway.
* Move SCHED2 trace points to post_schedule()Bjoern Brandenburg2012-10-18
| | | | | | | | | | Linux's post_schedule() scheduling class hook more closely matches what SCHED2 is supposed to trace, namely any scheduling overhead after the context switch. The prior trace points caught timers being armed from finish_switch(), which is already included in the context switch cost CXS. (This patch essentially reverts 8fe2fb8bb1c1cd0194608bc783d0ce7029e8d869).
* Feather-Trace: hide irq in SEND_RESCHED_ENDBjoern Brandenburg2012-10-18
| | | | | | | SEND_RESCHED_END is necessarily preceded by an interrupt. We don't want to filter events based on this expected interrupts, but we still want to detect samples disturbed by other interrupts. Hence, subtract one off the interrupt count.
* Trace IPI-related IRQs with ft_irq_fired()Bjoern Brandenburg2012-10-18
| | | | | | | | | IPIs have some special cases where irq_enter() is not called. This caused ft_irq_fired() to "miss" some rescheduling-related interrupts, which in turn may cause outliers. This patch makes sure ft_irq_fired() is called on scheduling-related IPIs.
* Mark feather-trace buffers as "disturbed" on soft IRQsBjoern Brandenburg2012-10-18
| | | | | We don't want outliers due to soft IRQs, so let them mark ongoing traces as "dirty" as well.
* Make Feather-Trace timestamp collection non-preemptiveBjoern Brandenburg2012-10-18
| | | | | | | | | | | If the tracing code is interrupted / preempted inbetween the time that a sequence number is drawn and the time that the trace recorded is allocated, then the trace file will contain "out of order" events. These are difficult to detect during post-processing and can create artificial "outliers". This patch briefly disables local interrutps to avoid this. While at it, de-duplicate the timestamp recording code.
* Use user-provided irq count for TS_SYSCALL_IN_ENDBjoern Brandenburg2012-10-18
| | | | | | To detect interrupts that interfered after the initial time stamp was recorded, this patch changes sched_trace to also record the IRQ count as observed by userspace.
* Export IRQ count to control pageBjoern Brandenburg2012-10-18
| | | | Also add some compile-time checks to detect unexpected offsets.
* Feather-Trace: add support for locking-related syscall overheadsBjoern Brandenburg2012-10-18
| | | | | Support recording timestamps that allow tracing the entry and exit costs of locking-related system calls.
* Feather-Trace: update locking timestampsBjoern Brandenburg2012-10-18
| | | | | Reassing locking timestamps and prepare support for tracing system call overheads.
* Feather-Trace: keep track of PID in trace recordBjoern Brandenburg2012-10-18
| | | | | | | | To properly trace locking overheads, it is required to tell apart samples from different tasks, which requires keeping track of their PIDs. The timestamp is shortened to 48 bits to make room for the PID.
* ftdev: don't hold lock while sleepingBjoern B. Brandenburg2012-10-18
| | | | Holding the lock prevents other tasks from opening the device.
* FDSO: make sure fdso_close() is called during task teardownBjoern Brandenburg2012-10-18
| | | | | | | When a task exists and its FDSO table is released, the locking protocol's 'close()' callback should be invoked to do proper protocol-specific cleanup (such as unlocking the resource, if required).
* Remove complete_n() APIBjoern Brandenburg2012-10-18
| | | | | | The LITMUS^RT-specific completion API complete_n() is no longer required by the synchronous release code. Let's remove it; one less modification of a core Linux file to maintain during rebasing.
* Re-implement synchronous task set release supportBjoern Brandenburg2012-10-18
| | | | | | | | | The old implementation had the problem that the first job release of all tasks was handled on the *same* CPU (that triggered the synchronous task set release). This could result in significant latency spikes. The new implementation uses a completion per task. Futher, each task programs its own release, which ensures that it will be on the proper processor.
* Fix compilation error on ARM platforms.Christopher Kenna2012-09-29
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* Fix 64-bit division in fpmath.hChristopher Kenna2012-09-29
| | | | | | Commit e6f51fb826ce98d436f445aae4eb9e9dba1f30e8 added some floating point support for LITMUS^RT, but it used 64-bit division that ARM does not support. Therefore, use the division functions from math64.h.
* EDF priority tie-breaks.Glenn Elliott2012-09-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of tie-breaking by PID (which is a static priority tie-break), we can tie-break by other job-level-unique parameters. This is desirable because tasks are equaly affected by tardiness since static priority tie-breaks cause tasks with greater PID values to experience the most tardiness. There are four tie-break methods: 1) Lateness. If two jobs, J_{1,i} and J_{2,j} of tasks T_1 and T_2, respectively, have equal deadlines, we favor the job of the task that had the worst lateness for jobs J_{1,i-1} and J_{2,j-1}. Note: Unlike tardiness, lateness may be less than zero. This occurs when a job finishes before its deadline. 2) Normalized Lateness. The same as #1, except lateness is first normalized by each task's relative deadline. This prevents tasks with short relative deadlines and small execution requirements from always losing tie-breaks. 3) Hash. The job tuple (PID, Job#) is used to generate a hash. Hash values are then compared. A job has ~50% chance of winning a tie-break with respect to another job. Note: Emperical testing shows that some jobs can have +/- ~1.5% advantage in tie-breaks. Linux's built-in hash function is not totally a uniform hash. 4) PIDs. PID-based tie-break used in prior versions of Litmus.
* Improve readability of EDF comparisons.Glenn Elliott2012-09-21
| | | | | | Restructured the EDF task comparison code to improve readability. Recoded chained logical expression embedded in return statement into a series of if/else blocks.
* Do processor state transitions in schedule_tail().Glenn Elliott2012-09-21
| | | | | | | | | Fixes a bug in Litmus where processor scheduling states could become corrupted. Corruption can occur when a just-forked thread is externally forced to be scheduled by SCHED_LITMUS before this just-forked thread can complete post-fork processing. Specifically, before schedule_tail() has completed.
* Include a missing header file.Christopher Kenna2012-09-20
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* Fix changed task_struct field name.Christopher Kenna2012-09-20
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* Fix wake_up() preemptions under P-FP and PSN-EDFBjoern Brandenburg2012-08-14
| | | | | | | Due to some mistake in the past, PSN-EDF was missing a check for preemptions when a task resumes. P-FP adopted it by virtue of copy&paste. This patch makes sure that a preemption is triggered when a higher-priority task is added to the ready queue.
* New Feature: Arbitrary deadlines.2012.2Glenn Elliott2012-08-01
| | | | | | | | | | | | Added support for arbitrary deadlines. Constraint: Relative deadline must be >= exec cost. Use: Set relative deadline in rt_task::rdeadline. Set value to 0 to default to implicit deadlines. Limitations: PFAIR not supported by this patch. PFAIR updated to reject tasks that do not have implicit deadlines.
* control page: avoid "minor" page faultsBjoern Brandenburg2012-07-23
| | | | | | | | | By default, even private writable pages are mapped with the RW bit disabled in the PTE. This causes a "minor" page fault when the page is first written to. To avoid this, make sure that vm_inert_page() uses the proper page protection bits and mark the VMA as VM_IO to keep the rest of the VM code out.
* control page: warn on page faultBjoern Brandenburg2012-07-23
| | | | | Page faults should not happen here. Scream if they do anyway. This is useful when extending the control page.
* control page: use vm_insert_page() instead of remap_pfn_range()Bjoern Brandenburg2012-07-23
| | | | | | vm_insert_page() is the simpler and preferred interface for remapping individual pages and includes additional error checks. It suffices for our purposes, so let's use it instead.
* P-FP: reject tasks with invalid prioritiesBjoern Brandenburg2012-07-23
| | | | | | The existing admission test failed to test for too-low priorities. Use the common macro to accept only valid priorities.
* P-FP: Clarify meaning of prioritiesBjoern Brandenburg2012-07-23
| | | | | | Add a comment to explain how priorities are interpreted, and provide some useful macros for userspace.
* P-FP: fix build bug if !CONFIG_RELEASE_MASTERBjoern Brandenburg2012-07-23
| | | | | Move declaration of 'cpu' out of #ifdef block, it's also needed for CONFIG_LITMUS_LOCKING.
* P-FP: make PCP available to userspaceSven Dziadek2012-07-23
| | | | Prior to that it was only used internally for DPCP
* P-FP: port P-FP plugin used in B. Brandenburg'sSven Dziadek2012-07-23
| | | | | | | | | | dissertation (branch bbb-diss) to current version of litmus This is needed for ongoing projects I took the unchanged code but removed some leftovers of OMLP which is not implemented
* Update to improved x86 Feather-Trace triggersBjoern Brandenburg2012-06-26
| | | | | | | | | | This patch imports recent upstream changes in Feather-Trace that reduce register pressure around Feather-Trace triggers. References: Commits 00713b8 and 225d734 in Feather-Trace. https://github.com/brandenburg/feather-trace/commit/00713b878636867ce07291c588509b38fa5bf152 https://github.com/brandenburg/feather-trace/commit/225d7348a08682cd87f72b127142bdfd6c0c7890
* C-EDF: do not requeue jobs without budgetBjoern Brandenburg2012-05-31
| | | | | | This patch replicates the fix in commit f141d730e91283a9bb5cfcb134fcead55d5da0c6 (which applies to GSN-EDF).
* GSN-EDF: do not requeue jobs without budgetBjoern Brandenburg2012-05-31
| | | | | | | | | | This patch changes how preemptions of jobs without budget work. Instead of requeuing them, they are now only added if they are not subject to budget enforcement or if they have non-zero budget. This allows us to process job completions that race with preemptions. This appears to fix a BUG in budget.c:65 reported by Giovani Gracioli.