Provide mechanism to discard data - #695
devreal wants to merge 9 commits into
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| item = (parsec_list_item_t*)item->list_next; /* conversion needed for volatile */ | ||
| if( 0 == gpu_copy->readers ) { | ||
| if (cpu_copy->flags & PARSEC_DATA_FLAG_DISCARDED) { | ||
| parsec_list_item_ring_chop((parsec_list_item_t*)gpu_copy); |
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And here.
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Same as above. The flag isn't changed and the device copy maintains a reference on the data_t so if we miss the update of the flags here we will evict into the host copy and then release everything.
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Add a function `parsec_data_discard` that releases the data such that the host copy remains intact but does not prevent destruction of the data once all device copies have been released. This keeps the host copy available for device copies to inspect and avoids potential race conditions in the release process. During an eviction, copies of data with a discarded host copy are not transfered but put directly into the lru. Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Otherwise we cannot destroy empty or discarded data. Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Also OR the flag instead of assigning it. Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Discarded data may never be pushed back so don't warn about it still being owned by the device. Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Discarded data sit toward the end of the lru while the data to be evicted is at the front. We walk both forward and backward to collect the discarded data from the back, until we either meet the pivot or we found enough data to evict. If we discarded data we don't evict. Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
therault
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Discussed during the call, issues raised are addressed and this is performance / feature - critical for MRA, so we should merge.
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will review that it doesn't break dplasma and merge |
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I modified this PR so that parsec_data_discard notifies the device(s) about discarded data. If the device finds that it has discarded data, it will try to release that data. Otherwise we don't the pay the cost of iterating through the LRU. This simplified the w2r task creation back to something sane(r) I had earlier. |
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We only try to find discarded data if we know that there is discarded data. If no one discarded data (e.g., DPLASMA) we don't go look for it. This is also needed to properly clean up discarded data before releasing the zone allocator. Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
| #endif | ||
| }; | ||
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| static inline void release_discarded_data(parsec_device_gpu_module_t *gpu_device, parsec_gpu_data_copy_t* gpu_copy) |
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compiler says this function is not used.
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This may not be needed anymore if we get parsec_data_release_self_contained_data from #671: https://github.com/ICLDisco/parsec/pull/671/files#diff-b76b62ea20f19d97740a2221cabf57210f9f97991c0ef635ca0cafcc4c3c40d1R596 |
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Add a function parsec_data_discard that releases the data such that the host copy remains intact but does not prevent destruction of the data once all device copies have been released. This keeps the host copy available for device copies to inspect and avoids potential race conditions in the release process. During an eviction, copies of data with a discarded host copy are not transfered but put directly into the lru.
Replaces some duplicated code with a call to parsec_device_release_gpu_copy.