- Sep 19, 2007
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Andre Detsch authored
Affinity reference point location (gang->aff_ref_spu) is reset when the whole gang is descheduled. However, the last member of a gang can be descheduled while we are trying to schedule another member of the gang. This was leading to a race condition, and the code was using gang->aff_ref_spu in an unsafe manner. By holding the gang->aff_mutex a little bit longer, and increment gang->aff_sched_count (which controls when gang->aff_ref_spu should be reset) a little bit earlier, the problem is fixed. Signed-off-by:
Andre Detsch <adetsch@br.ibm.com> Signed-off-by:
Jeremy Kerr <jk@ozlabs.org> Signed-off-by:
Paul Mackerras <paulus@samba.org>
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- Aug 03, 2007
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Andre Detsch authored
This patch fixes affinity reference point placement, which was not being done in some situations, after the introduction of node_allowed() calls. The previously used parameter, 'ctx', is just the iterator of the previous list_for_each_entry_reverse loop, and its value might be invalid at the end of the loop. Also, the right context to seek for information when defining the reference ctx location _is_ the reference ctx. Signed-off-by:
Arnd Bergmann <arnd.bergmann@de.ibm.com> Signed-off-by:
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- Jul 26, 2007
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Masato Noguchi authored
We currently initialize cbe_spu_info[].spus in both init_spu_base and spu_sched_init. The initialise in spu_sched_init clears the SPU list, so we end up with no physical SPUs. Because of this, the spu_run syscall will block forever. This change removes the unnecessary initialization in spu_sched_init. Signed-off-by:
Masato Noguchi <Masato.Noguchi@jp.sony.com> Signed-off-by:
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- Jul 20, 2007
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Christoph Hellwig authored
This sorts out the various lists and related locks in the spu code. In detail: - the per-node free_spus and active_list are gone. Instead struct spu gained an alloc_state member telling whether the spu is free or not - the per-node spus array is now locked by a per-node mutex, which takes over from the global spu_lock and the per-node active_mutex - the spu_alloc* and spu_free function are gone as the state change is now done inline in the spufs code. This allows some more sharing of code for the affinity vs normal case and more efficient locking - some little refactoring in the affinity code for this locking scheme Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Bob Nelson authored
From: Maynard Johnson <mpjohn@us.ibm.com> This patch updates the existing arch/powerpc/oprofile/op_model_cell.c to add in the SPU profiling capabilities. In addition, a 'cell' subdirectory was added to arch/powerpc/oprofile to hold Cell-specific SPU profiling code. Exports spu_set_profile_private_kref and spu_get_profile_private_kref which are used by OProfile to store private profile information in spufs data structures. Also incorporated several fixes from other patches (rrn). Check pointer returned from kzalloc. Eliminated unnecessary cast. Better error handling and cleanup in the related area. 64-bit unsigned long parameter was being demoted to 32-bit unsigned int and eventually promoted back to unsigned long. Signed-off-by:
Carl Love <carll@us.ibm.com> Signed-off-by:
Maynard Johnson <mpjohn@us.ibm.com> Signed-off-by:
Bob Nelson <rrnelson@us.ibm.com> Signed-off-by:
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Bob Nelson authored
From: Maynard Johnson <mpjohn@us.ibm.com> This patch adds to the capability of spu_switch_event_register so that the caller is also notified of currently active SPU tasks. Exports spu_switch_event_register and spu_switch_event_unregister so that OProfile can get access to the notifications provided. Signed-off-by:
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Arnd Bergmann authored
This patch makes the scheduller honor affinity information for each context being scheduled. If the context has no affinity information, behaviour is unchanged. If there are affinity information, context is schedulled to be run on the exact spu recommended by the affinity placement algorithm. Signed-off-by:
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Arnd Bergmann authored
This patch provides the spu affinity placement logic for the spufs scheduler. Each time a gang is going to be scheduled, the placement of a reference context is defined. The placement of all other contexts with affinity from the gang is defined based on this reference context location and on a precomputed displacement offset. Signed-off-by:
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Arnd Bergmann authored
Addition of a spufs-global "cbe_info" array. Each entry contains information about one Cell/B.E. node, namelly: * list of spus (both free and busy spus are in this list); * list of free spus (replacing the static spu_list from spu_base.c) * number of spus; * number of reserved (non scheduleable) spus. SPE affinity implementation actually requires only access to one spu per BE node (since it implements its own pointer to walk through the other spus of the ring) and the number of scheduleable spus (n_spus - non_sched_spus) However having this more general structure can be useful for other functionalities, concentrating per-cbe statistics / data. Signed-off-by:
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Masato Noguchi authored
spu_sched->bitmap has MAX_PRIO(=140) width in bits.However, since ff80a77f, sched_find_first_bit() only supports 100-bit bitmaps. Thus, spu_sched->bitmap should be treated by generic find_first_bit(). Signed-off-by:
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Andre Detsch authored
This patch exports per-context statistics in spufs as long as spu statistics in sysfs. It was formed by merging: "spufs: add spu stats in sysfs" From: Christoph Hellwig "spufs: add stat file to spufs" From: Christoph Hellwig "spufs: fix libassist accounting" From: Jeremy Kerr "spusched: fix spu utilization statistics" From: Luke Browning And some adjustments by myself, after suggestions on cbe-oss-dev. Having separate patches was making the review process harder than it should, as we end up integrating spus and ctx statistics accounting much more than it was on the first implementation. Signed-off-by:
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Jeremy Kerr authored
In 6cbf93960e64f313f6e247cbca7afaa50e3ee2c we added a WARN_ON for calling spu_deactivate on contexts created with the SPU_CREATE_NOSCHED flag. However, all NOSCHED contexts will need to be deactivated when the context is destroyed, so this gives a spurious warning when any NOSCHED context is closed. This change removes the WARN_ON. Signed-off-by:
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Sebastian Siewior authored
WARNING: arch/powerpc/platforms/cell/spufs/spufs.o(.init.text+0x158): Section mismatch: reference to .exit.text:.spu_sched_exit (between '.init_module' and '.spu_sched_init') was introduced by c99c1994 This patch removes the warning. Cc: Christoph Hellwig <hch@lst.de> Signed-off-by:
Sebastian Siewior <sebastian@breakpoint.cc> Signed-off-by:
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- Jul 03, 2007
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Christoph Hellwig authored
Export spu statistics in sysfs. Signed-off-by:
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Christoph Hellwig authored
spu_activate can be called from multiple threads at the same time on behalf of the same spu context. We need to make sure to only add it once to avoid runqueue corruption. Signed-off-by:
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Christoph Hellwig authored
Only enable the scheduler tick if we have any context waiting to be scheduled. Signed-off-by:
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Christoph Hellwig authored
Export per-context statistics in spufs. Signed-off-by:
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Christoph Hellwig authored
Provide load average information for spu context. The format is identical to /proc/loadavg, which is also where a lot of code and concepts is borrowed from. Signed-off-by:
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Christoph Hellwig authored
The new tid file contains the ID of the thread currently running the context, if any. This is used so that the new spu-top and spu-ps tools can find the thread in /proc. Signed-off-by:
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Jeremy Kerr authored
Remove redundant whitespace in arch/powerpc/platforms/cell/spufs/ Signed-off-by:
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Christoph Hellwig authored
And last but not least we need to make sure the scheduler tick never preempts a nosched context. Signed-off-by:
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Christoph Hellwig authored
spu_deactivate should never be called for nosched contets. Put in a check so we can print a stacktrace and exit early in case it happes erroneously. Signed-off-by:
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Christoph Hellwig authored
Add a cpus_allowed allowed filed to struct spu_context so that we always use the cpu mask of the owning thread instead of the one happening to call into the scheduler. Also use this information in grab_runnable_context to avoid spurious wakeups. Signed-off-by:
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Christoph Hellwig authored
Update scheduling information on every spu_run to allow for setting threads to realtime priority just before running them. This requires some slightly ugly code in spufs_run_spu because we can just update the information unlocked if the spu is not runnable, but we need to acquire the active_mutex when it is runnable to protect against find_victim. This locking scheme requires opencoding spu_acquire_runnable in spufs_run_spu which actually is a nice cleanup all by itself. Signed-off-by:
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Jeremy Kerr authored
Print out a few scheduler tuning parameters when we've compiled with DEBUG defined. Signed-off-by:
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Jeremy Kerr authored
The current timeslice code mixes 'jiffies' up with 'spesched ticks'. This change correctly defines the number of time slices each SPE contexts is given, and clarifies the comment. This brings the default timeslice for SPE contexts into a reasonable range. Signed-off-by:
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Christoph Hellwig authored
Enable preemptive scheduling for non-RT contexts. We use the same algorithms as the CPU scheduler to calculate the time slice length, and for now we also use the same timeslice length as the CPU scheduler. This might be not enough for good performance and can be changed after some benchmarking. Note that currently we do not boost the priority for contexts waiting on the runqueue for a long time, so contexts with a higher nice value could starve ones with less priority. This could easily be fixed once the rework of the spu lists that Luke and I discussed is done. Signed-off-by:
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Christoph Hellwig authored
Get rid of the scheduler workqueues that complicated things a lot to a dedicated spu scheduler thread that gets woken by a traditional scheduler tick. By default this scheduler tick runs a HZ * 10, aka one spu scheduler tick for every 10 cpu ticks. Currently the tick is not disabled when we have less context than available spus, but I will implement this later. Signed-off-by:
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- Jun 07, 2007
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Christoph Hellwig authored
Nosched context sould never be scheduled out, thus we must not deactivate them in spu_yield ever. Signed-off-by:
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Christoph Hellwig authored
Fix the race between checking for contexts on the runqueue and actually waking them in spu_deactive and spu_yield. The guts of spu_reschedule are split into a new helper called grab_runnable_context which shows if there is a runnable thread below a specified priority and if yes removes if from the runqueue and uses it. This function is used by the new __spu_deactivate hepler shared by preemption and spu_yield to grab a new context before deactivating a specified priority and if yes removes if from the runqueue and uses it. This function is used by the new __spu_deactivate hepler shared by preemption and spu_yield to grab a new context before deactivating the old one. Signed-off-by:
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- May 08, 2007
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Randy Dunlap authored
Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- Apr 23, 2007
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Luke Browning authored
Addition to stop_wq needs to happen before adding to the runqeueue and under the same lock so that we don't have a race window for a lost wake up in the spu scheduler. Signed-off-by:
Luke Browning <lukebrowning@us.ibm.com> Signed-off-by:
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Christoph Hellwig authored
A single context should only be woken once, and we should not have more wakeups for a given priority than the number of contexts on that runqueue position. Also add some asserts to trap future problems in this area more easily. Signed-off-by:
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Arnd Bergmann authored
set_bit does not guarantee ordering on powerpc, so using it for communication between threads requires explicit mb() calls. Signed-off-by: -
Christoph Hellwig authored
To not lose a spu thread we need to make sure it always gets put back on the runqueue. In find_victim aswell as in the scheduler tick as done in the previous patch. Signed-off-by:
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Christoph Hellwig authored
To not lose a spu thread we need to make sure it always gets put back on the runqueue. Signed-off-by:
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Christoph Hellwig authored
The scheduler workqueue may rearm itself and deadlock when we try to stop it. Put a flag in place to avoid skip the work if we're tearing down the context. Signed-off-by:
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- Apr 12, 2007
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Christoph Hellwig authored
There is no reason to yield the CPU in spu_yield - if the backing thread reenters spu_run it gets added to the end of the runqueue for it's priority. So the yield is just a slowdown for the case where we have higher priority contexts waiting. Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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- Mar 09, 2007
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Benjamin Herrenschmidt authored
The SPU code doesn't properly invalidate SPUs SLBs when necessary, for example when changing a segment size from the hugetlbfs code. In addition, it saves and restores the SLB content on context switches which makes it harder to properly handle those invalidations. This patch removes the saving & restoring for now, something more efficient might be found later on. It also adds a spu_flush_all_slbs(mm) that can be used by the core mm code to flush the SLBs of all SPEs that are running a given mm at the time of the flush. In order to do that, it adds a spinlock to the list of all SPEs and move some bits & pieces from spufs to spu_base.c Signed-off-by:Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Christoph Hellwig authored
This optimization was added recently but is still buggy, so back it out for now. Signed-off-by:
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