1. OCR User Hints API Rob, Sanjay, Zoran

2. Motivation for OCR user hints API Create a facility for the OCR application developer to provide application specific information to the runtime as hints A valid OCR program does not depend on the presence of hints OCR hints are always optional The runtime may use OCR user hints to help with the execution of the program E.g: the scheduler may choose to ignore some user hints

3. OCR User Hints API Overview Example usage: ocrHint_t myHint; ocrHintInit(&myHint); ocrSetHintProperty(&myHint, ….); ocrSetHint(destGuid, &myHint); User hints in OCR are variables of type ocrHint_t ( e.g. ocrHint_t myHint; ) u8 ocrHintInit(ocrHint_t *hint); Initializes hint u8 ocrSetHintProperty(ocrHint_t *hint, ocrHintProp_t hintProperty, void *value); sets a specific property to the hint u8 ocrGetHintProperty(ocrHint_t *hint, ocrHintProp_t hintProperty, void *value); reads a specific property from the hint u8 ocrSetHint(ocrGuid_t guid, ocrHint_t *hint); sets the hint for an OCR guid object u8 ocrGetHint(ocrGuid_t guid, ocrHint_t *hint); Gets the hints from an OCR guid object

4. OCR Affinity Groups OCR affinity groups are containers for a group of EDTs / DBs / Events and other affinity groups The user can specify hints for all members belonging to that affinity group API u8 ocrAffinityCreate(ocrGuid_t * affinityGuid, ocrGuid_t parentGuid, u32 property); Create an affinity guid u8 ocrSetAffinity(ocrGuid_t dstDuid, ocrGuid_t affinityGuid); Sets the affinity for another EDT/DB/Event (dstGuid) If dstGuid is another affinity guid, then dstGuid’s parent is set to be affinityGuid u8 ocrGetAffinity(ocrGuid_t dstGuid, ocrGuid_t * affinityGuid); Get the associated affinity guid from dstGuid If dstGuid is of affinity type, then its parent is returned

5. OCR hints for temporal locality and bandwidth/compute bounds Zoran

6. Temporal locality Grouping EDTs that work on the same data “together” to take advantage of warm caches only makes sense if they are close in BOTH space and time Introduce a notion of time: phases ocrGuid_t affinityGuid, edt1, edt2, thisguid; ocrHint_t myHint, thisHint; u64 curPhase; ocrHintInit(&myHint); ocrGetHint(thisguid, &thisHint); ocrGetHintProperty(&thisHint, OCR_HINT_PROP_AFFINITY_PHASE, (void*)&curPhase); // create a phase hint for current phase + 5 u64 newPhase = curPhase + 5; // phase is always relative ocrSetHintProperty(&myHint, OCR_HINT_PROP_AFFINITY_PHASE, (void*)&newPhase); ocrAffinityCreate(&affinityGuid, NULL_GUID, 0); ocrSetHint(affinityGuid, &myHint); ocrEdtCreate(&edt1,…, affinityGuid, …); ocrEdtCreate(&edt2,…, affinityGuid, …);