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view MasterLoop.c @ 130:5475f90c248a
fix outputs (dependency file creation, counter length)
| author | Nina Engelhardt |
|---|---|
| date | Wed, 07 Sep 2011 13:26:30 +0200 |
| parents | ce02441b77cf |
| children | 395f58384a5c |
line source
1 /*
2 * Copyright 2010 OpenSourceStewardshipFoundation
3 *
4 * Licensed under BSD
5 */
9 #include <stdio.h>
10 #include <stddef.h>
12 #include "VMS.h"
13 #include "ProcrContext.h"
16 //===========================================================================
17 void inline
18 stealWorkInto( SchedSlot *currSlot, VMSQueueStruc *readyToAnimateQ,
19 VirtProcr *masterPr );
21 //===========================================================================
25 /*This code is animated by the virtual Master processor.
26 *
27 *Polls each sched slot exactly once, hands any requests made by a newly
28 * done slave to the "request handler" plug-in function
29 *
30 *Any slots that need a virt procr assigned are given to the "schedule"
31 * plug-in function, which tries to assign a virt procr (slave) to it.
32 *
33 *When all slots needing a processor have been given to the schedule plug-in,
34 * a fraction of the procrs successfully scheduled are put into the
35 * work queue, then a continuation of this function is put in, then the rest
36 * of the virt procrs that were successfully scheduled.
37 *
38 *The first thing the continuation does is busy-wait until the previous
39 * animation completes. This is because an (unlikely) continuation may
40 * sneak through queue before previous continuation is done putting second
41 * part of scheduled slaves in, which is the only race condition.
42 *
43 */
45 /*May 29, 2010 -- birth a Master during init so that first core loop to
46 * start running gets it and does all the stuff for a newly born --
47 * from then on, will be doing continuation, but do suspension self
48 * directly at end of master loop
49 *So VMS__init just births the master virtual processor same way it births
50 * all the others -- then does any extra setup needed and puts it into the
51 * work queue.
52 *However means have to make masterEnv a global static volatile the same way
53 * did with readyToAnimateQ in core loop. -- for performance, put the
54 * jump to the core loop directly in here, and have it directly jump back.
55 *
56 *
57 *Aug 18, 2010 -- Going to a separate MasterVP for each core, to see if this
58 * avoids the suspected bug in the system stack that causes bizarre faults
59 * at random places in the system code.
60 *
61 *So, this function is coupled to each of the MasterVPs, -- meaning this
62 * function can't rely on a particular stack and frame -- each MasterVP that
63 * animates this function has a different one.
64 *
65 *At this point, the masterLoop does not write itself into the queue anymore,
66 * instead, the coreLoop acquires the masterLock when it has nothing to
67 * animate, and then animates its own masterLoop. However, still try to put
68 * several AppVPs into the queue to amortize the startup cost of switching
69 * to the MasterVP. Note, don't have to worry about latency of requests much
70 * because most requests generate work for same core -- only latency issue
71 * is case when other cores starved and one core's requests generate work
72 * for them -- so keep max in queue to 3 or 4..
73 */
74 void masterLoop( void *initData, VirtProcr *animatingPr )
75 {
76 int32 slotIdx, numSlotsFilled;
77 VirtProcr *schedVirtPr;
78 SchedSlot *currSlot, **schedSlots;
79 MasterEnv *masterEnv;
80 VMSQueueStruc *readyToAnimateQ;
82 SlaveScheduler slaveScheduler;
83 RequestHandler requestHandler;
84 void *semanticEnv;
86 int32 thisCoresIdx;
87 VirtProcr *masterPr;
88 volatile VirtProcr *volatileMasterPr;
90 volatileMasterPr = animatingPr;
91 masterPr = (VirtProcr*)volatileMasterPr; //used to force re-define after jmp
93 //First animation of each MasterVP will in turn animate this part
94 // of setup code.. (VP creator sets up the stack as if this function
95 // was called normally, but actually get here by jmp)
96 //So, setup values about stack ptr, jmp pt and all that
97 //masterPr->nextInstrPt = &&masterLoopStartPt;
100 //Note, got rid of writing the stack and frame ptr up here, because
101 // only one
102 // core can ever animate a given MasterVP, so don't need to communicate
103 // new frame and stack ptr to the MasterVP storage before a second
104 // version of that MasterVP can get animated on a different core.
105 //Also got rid of the busy-wait.
108 //masterLoopStartPt:
109 while(1){
111 //============================= MEASUREMENT STUFF ========================
112 #ifdef MEAS__TIME_MASTER
113 //Total Master time includes one coreloop time -- just assume the core
114 // loop time is same for Master as for AppVPs, even though it may be
115 // smaller due to higher predictability of the fixed jmp.
116 saveLowTimeStampCountInto( masterPr->startMasterTSCLow );
117 #endif
118 //========================================================================
120 masterEnv = (MasterEnv*)_VMSMasterEnv;
122 //GCC may optimize so doesn't always re-define from frame-storage
123 masterPr = (VirtProcr*)volatileMasterPr; //just to make sure after jmp
124 thisCoresIdx = masterPr->coreAnimatedBy;
125 readyToAnimateQ = masterEnv->readyToAnimateQs[thisCoresIdx];
126 schedSlots = masterEnv->allSchedSlots[thisCoresIdx];
128 requestHandler = masterEnv->requestHandler;
129 slaveScheduler = masterEnv->slaveScheduler;
130 semanticEnv = masterEnv->semanticEnv;
133 //Poll each slot's Done flag
134 numSlotsFilled = 0;
135 for( slotIdx = 0; slotIdx < NUM_SCHED_SLOTS; slotIdx++)
136 {
137 currSlot = schedSlots[ slotIdx ];
139 if( currSlot->workIsDone )
140 {
141 currSlot->workIsDone = FALSE;
142 currSlot->needsProcrAssigned = TRUE;
144 //process requests from slave to master
145 //====================== MEASUREMENT STUFF ===================
146 #ifdef MEAS__TIME_PLUGIN
147 int32 startStamp1, endStamp1;
148 saveLowTimeStampCountInto( startStamp1 );
149 #endif
150 #ifdef MEAS__PERF_COUNTERS
151 int lastRecordIdx = currSlot->procrAssignedToSlot->counter_history_array_info->numInArray -1;
152 CounterRecord* lastRecord = currSlot->procrAssignedToSlot->counter_history[lastRecordIdx];
153 lastRecord->req_core = thisCoresIdx;
154 saveCyclesAndInstrs(thisCoresIdx,lastRecord->req_cycles,lastRecord->req_instrs);
155 //End of task, start of next task
156 //print counters from last run
157 print_record_csv_to_file(lastRecord,_VMSMasterEnv->counteroutput);
159 Dependency* newd = new_dependency(currSlot->procrAssignedToSlot->procrID,lastRecord->task_position,currSlot->procrAssignedToSlot->procrID,lastRecord->task_position + 1);
160 addToDynArray((void*) newd ,masterEnv->dependenciesInfo);
162 //print_record_human_readable(lastRecord);
163 //create new entry in record array
164 CounterRecord* newRecord = VMS__malloc(sizeof(CounterRecord));
165 newRecord->req_core = thisCoresIdx;
166 newRecord->vp_id = currSlot->procrAssignedToSlot->procrID;
167 newRecord->task_position = lastRecord->task_position + 1;
168 getReturnAddressBeforeLibraryCall(currSlot->procrAssignedToSlot, &(newRecord->addr_of_libcall_for_req));
169 addToDynArray( (void*) newRecord, currSlot->procrAssignedToSlot->counter_history_array_info);
170 lastRecord = newRecord;
171 #endif
172 //============================================================
173 (*requestHandler)( currSlot->procrAssignedToSlot, semanticEnv );
174 //====================== MEASUREMENT STUFF ===================
175 #ifdef MEAS__TIME_PLUGIN
176 saveLowTimeStampCountInto( endStamp1 );
177 addIntervalToHist( startStamp1, endStamp1,
178 _VMSMasterEnv->reqHdlrLowTimeHist );
179 addIntervalToHist( startStamp1, endStamp1,
180 _VMSMasterEnv->reqHdlrHighTimeHist );
181 #endif
182 #ifdef MEAS__PERF_COUNTERS
183 //done with constraints check
184 saveCyclesAndInstrs(thisCoresIdx,lastRecord->sc_done_cycles,lastRecord->sc_done_instrs);
185 saveLowTimeStampCountInto(lastRecord->blocked_timestamp);
186 #endif
187 //============================================================
188 }
189 if( currSlot->needsProcrAssigned )
190 { //give slot a new virt procr
191 #ifdef MEAS__PERF_COUNTERS
192 //start assigner
193 uint64 tmp_cycles;
194 uint64 tmp_instrs;
195 saveCyclesAndInstrs(thisCoresIdx,tmp_cycles,tmp_instrs);
196 #endif
197 schedVirtPr =
198 (*slaveScheduler)( semanticEnv, thisCoresIdx );
200 if( schedVirtPr != NULL )
201 { currSlot->procrAssignedToSlot = schedVirtPr;
202 schedVirtPr->schedSlot = currSlot;
203 currSlot->needsProcrAssigned = FALSE;
204 numSlotsFilled += 1;
205 #ifdef MEAS__PERF_COUNTERS
206 //end assigner
207 int lastRecordIdx = currSlot->procrAssignedToSlot->counter_history_array_info->numInArray -1;
208 CounterRecord* lastRecord = currSlot->procrAssignedToSlot->counter_history[lastRecordIdx];
209 lastRecord->assigning_core = thisCoresIdx;
210 lastRecord->start_assign_cycles = tmp_cycles;
211 lastRecord->start_assign_instrs = tmp_instrs;
212 saveCyclesAndInstrs(thisCoresIdx,lastRecord->end_assign_cycles,lastRecord->end_assign_instrs);
213 #endif
214 writeVMSQ( schedVirtPr, readyToAnimateQ );
215 }
216 }
217 }
220 #ifdef USE_WORK_STEALING
221 //If no slots filled, means no more work, look for work to steal.
222 if( numSlotsFilled == 0 )
223 { gateProtected_stealWorkInto( currSlot, readyToAnimateQ, masterPr );
224 }
225 #endif
228 #ifdef MEAS__TIME_MASTER
229 saveLowTimeStampCountInto( masterPr->endMasterTSCLow );
230 #endif
232 masterSwitchToCoreLoop(animatingPr);
233 flushRegisters();
234 }//MasterLoop
237 }
241 /*This has a race condition -- the coreloops are accessing their own queues
242 * at the same time that this work-stealer on a different core is trying to
243 */
244 void inline
245 stealWorkInto( SchedSlot *currSlot, VMSQueueStruc *readyToAnimateQ,
246 VirtProcr *masterPr )
247 {
248 VirtProcr *stolenPr;
249 int32 coreIdx, i;
250 VMSQueueStruc *currQ;
252 stolenPr = NULL;
253 coreIdx = masterPr->coreAnimatedBy;
254 for( i = 0; i < NUM_CORES -1; i++ )
255 {
256 if( coreIdx >= NUM_CORES -1 )
257 { coreIdx = 0;
258 }
259 else
260 { coreIdx++;
261 }
262 currQ = _VMSMasterEnv->readyToAnimateQs[coreIdx];
263 if( numInVMSQ( currQ ) > 0 )
264 { stolenPr = readVMSQ (currQ );
265 break;
266 }
267 }
269 if( stolenPr != NULL )
270 { currSlot->procrAssignedToSlot = stolenPr;
271 stolenPr->schedSlot = currSlot;
272 currSlot->needsProcrAssigned = FALSE;
274 writeVMSQ( stolenPr, readyToAnimateQ );
275 }
276 }
278 /*This algorithm makes the common case fast. Make the coreloop passive,
279 * and show its progress. Make the stealer control a gate that coreloop
280 * has to pass.
281 *To avoid interference, only one stealer at a time. Use a global
282 * stealer-lock.
283 *
284 *The pattern is based on a gate -- stealer shuts the gate, then monitors
285 * to be sure any already past make it all the way out, before starting.
286 *So, have a "progress" measure just before the gate, then have two after it,
287 * one is in a "waiting room" outside the gate, the other is at the exit.
288 *Then, the stealer first shuts the gate, then checks the progress measure
289 * outside it, then looks to see if the progress measure at the exit is the
290 * same. If yes, it knows the protected area is empty 'cause no other way
291 * to get in and the last to get in also exited.
292 *If the progress measure at the exit is not the same, then the stealer goes
293 * into a loop checking both the waiting-area and the exit progress-measures
294 * until one of them shows the same as the measure outside the gate. Might
295 * as well re-read the measure outside the gate each go around, just to be
296 * sure. It is guaranteed that one of the two will eventually match the one
297 * outside the gate.
298 *
299 *Here's an informal proof of correctness:
300 *The gate can be closed at any point, and have only four cases:
301 * 1) coreloop made it past the gate-closing but not yet past the exit
302 * 2) coreloop made it past the pre-gate progress update but not yet past
303 * the gate,
304 * 3) coreloop is right before the pre-gate update
305 * 4) coreloop is past the exit and far from the pre-gate update.
306 *
307 * Covering the cases in reverse order,
308 * 4) is not a problem -- stealer will read pre-gate progress, see that it
309 * matches exit progress, and the gate is closed, so stealer can proceed.
310 * 3) stealer will read pre-gate progress just after coreloop updates it..
311 * so stealer goes into a loop until the coreloop causes wait-progress
312 * to match pre-gate progress, so then stealer can proceed
313 * 2) same as 3..
314 * 1) stealer reads pre-gate progress, sees that it's different than exit,
315 * so goes into loop until exit matches pre-gate, now it knows coreloop
316 * is not in protected and cannot get back in, so can proceed.
317 *
318 *Implementation for the stealer:
319 *
320 *First, acquire the stealer lock -- only cores with no work to do will
321 * compete to steal, so not a big performance penalty having only one --
322 * will rarely have multiple stealers in a system with plenty of work -- and
323 * in a system with little work, it doesn't matter.
324 *
325 *Note, have single-reader, single-writer pattern for all variables used to
326 * communicate between stealer and victims
327 *
328 *So, scan the queues of the core loops, until find non-empty. Each core
329 * has its own list that it scans. The list goes in order from closest to
330 * furthest core, so it steals first from close cores. Later can add
331 * taking info from the app about overlapping footprints, and scan all the
332 * others then choose work with the most footprint overlap with the contents
333 * of this core's cache.
334 *
335 *Now, have a victim want to take work from. So, shut the gate in that
336 * coreloop, by setting the "gate closed" var on its stack to TRUE.
337 *Then, read the core's pre-gate progress and compare to the core's exit
338 * progress.
339 *If same, can proceed to take work from the coreloop's queue. When done,
340 * write FALSE to gate closed var.
341 *If different, then enter a loop that reads the pre-gate progress, then
342 * compares to exit progress then to wait progress. When one of two
343 * matches, proceed. Take work from the coreloop's queue. When done,
344 * write FALSE to the gate closed var.
345 *
346 */
347 void inline
348 gateProtected_stealWorkInto( SchedSlot *currSlot,
349 VMSQueueStruc *myReadyToAnimateQ,
350 VirtProcr *masterPr )
351 {
352 VirtProcr *stolenPr;
353 int32 coreIdx, i, haveAVictim, gotLock;
354 VMSQueueStruc *victimsQ;
356 volatile GateStruc *vicGate;
357 int32 coreMightBeInProtected;
361 //see if any other cores have work available to steal
362 haveAVictim = FALSE;
363 coreIdx = masterPr->coreAnimatedBy;
364 for( i = 0; i < NUM_CORES -1; i++ )
365 {
366 if( coreIdx >= NUM_CORES -1 )
367 { coreIdx = 0;
368 }
369 else
370 { coreIdx++;
371 }
372 victimsQ = _VMSMasterEnv->readyToAnimateQs[coreIdx];
373 if( numInVMSQ( victimsQ ) > 0 )
374 { haveAVictim = TRUE;
375 vicGate = _VMSMasterEnv->workStealingGates[ coreIdx ];
376 break;
377 }
378 }
379 if( !haveAVictim ) return; //no work to steal, exit
381 //have a victim core, now get the stealer-lock
382 gotLock =__sync_bool_compare_and_swap( &(_VMSMasterEnv->workStealingLock),
383 UNLOCKED, LOCKED );
384 if( !gotLock ) return; //go back to core loop, which will re-start master
387 //====== Start Gate-protection =======
388 vicGate->gateClosed = TRUE;
389 coreMightBeInProtected= vicGate->preGateProgress != vicGate->exitProgress;
390 while( coreMightBeInProtected )
391 { //wait until sure
392 if( vicGate->preGateProgress == vicGate->waitProgress )
393 coreMightBeInProtected = FALSE;
394 if( vicGate->preGateProgress == vicGate->exitProgress )
395 coreMightBeInProtected = FALSE;
396 }
398 stolenPr = readVMSQ ( victimsQ );
400 vicGate->gateClosed = FALSE;
401 //======= End Gate-protection =======
404 if( stolenPr != NULL ) //victim could have been in protected and taken
405 { currSlot->procrAssignedToSlot = stolenPr;
406 stolenPr->schedSlot = currSlot;
407 currSlot->needsProcrAssigned = FALSE;
409 writeVMSQ( stolenPr, myReadyToAnimateQ );
410 }
412 //unlock the work stealing lock
413 _VMSMasterEnv->workStealingLock = UNLOCKED;
414 }