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comparison MasterLoop.c @ 218:82f7defac851

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Added backoff to core loop, cleaned up core loop code, cleaned comments
author Some Random Person <seanhalle@yahoo.com>
date Sat, 10 Mar 2012 21:48:53 -0800
parents a18539c0bc37
children
comparison
equal deleted inserted replaced
60:548ac2b6791d 62:adb18b284638
39 * sneak through queue before previous continuation is done putting second 39 * sneak through queue before previous continuation is done putting second
40 * part of scheduled slaves in, which is the only race condition. 40 * part of scheduled slaves in, which is the only race condition.
41 * 41 *
42 */ 42 */
43 43
44 /*May 29, 2010 -- birth a Master during init so that first core loop to 44 /*May 29, 2010 -- birth a Master during init so that first core controller to
45 * start running gets it and does all the stuff for a newly born -- 45 * start running gets it and does all the stuff for a newly born --
46 * from then on, will be doing continuation, but do suspension self 46 * from then on, will be doing continuation, but do suspension self
47 * directly at end of master loop 47 * directly at end of master loop
48 *So VMS_WL__init just births the master virtual processor same way it births 48 *So VMS_WL__init just births the master virtual processor same way it births
49 * all the others -- then does any extra setup needed and puts it into the 49 * all the others -- then does any extra setup needed and puts it into the
50 * work queue. 50 * work queue.
51 *However means have to make masterEnv a global static volatile the same way 51 *However means have to make masterEnv a global static volatile the same way
52 * did with readyToAnimateQ in core loop. -- for performance, put the 52 * did with readyToAnimateQ in core controller. -- for performance, put the
53 * jump to the core loop directly in here, and have it directly jump back. 53 * jump to the core controller directly in here, and have it directly jump back.
54 * 54 *
55 * 55 *
56 *Aug 18, 2010 -- Going to a separate MasterVP for each core, to see if this 56 *Aug 18, 2010 -- Going to a separate MasterVP for each core, to see if this
57 * avoids the suspected bug in the system stack that causes bizarre faults 57 * avoids the suspected bug in the system stack that causes bizarre faults
58 * at random places in the system code. 58 * at random places in the system code.
60 *So, this function is coupled to each of the MasterVPs, -- meaning this 60 *So, this function is coupled to each of the MasterVPs, -- meaning this
61 * function can't rely on a particular stack and frame -- each MasterVP that 61 * function can't rely on a particular stack and frame -- each MasterVP that
62 * animates this function has a different one. 62 * animates this function has a different one.
63 * 63 *
64 *At this point, the masterLoop does not write itself into the queue anymore, 64 *At this point, the masterLoop does not write itself into the queue anymore,
65 * instead, the coreLoop acquires the masterLock when it has nothing to 65 * instead, the coreCtlr acquires the masterLock when it has nothing to
66 * animate, and then animates its own masterLoop. However, still try to put 66 * animate, and then animates its own masterLoop. However, still try to put
67 * several AppSlvs into the queue to amortize the startup cost of switching 67 * several AppSlvs into the queue to amortize the startup cost of switching
68 * to the MasterVP. Note, don't have to worry about latency of requests much 68 * to the MasterVP. Note, don't have to worry about latency of requests much
69 * because most requests generate work for same core -- only latency issue 69 * because most requests generate work for same core -- only latency issue
70 * is case when other cores starved and one core's requests generate work 70 * is case when other cores starved and one core's requests generate work
162 } 162 }
163 #endif 163 #endif
164 164
165 MEAS__Capture_Post_Master_Point; 165 MEAS__Capture_Post_Master_Point;
166 166
167 masterSwitchToCoreLoop(animatingSlv); 167 masterSwitchToCoreCtlr(animatingSlv);
168 flushRegisters(); 168 flushRegisters();
169 }//MasterLoop 169 }//MasterLoop
170 170
171 171
172 } 172 }
258 * in a system with little work, it doesn't matter. 258 * in a system with little work, it doesn't matter.
259 * 259 *
260 *Note, have single-reader, single-writer pattern for all variables used to 260 *Note, have single-reader, single-writer pattern for all variables used to
261 * communicate between stealer and victims 261 * communicate between stealer and victims
262 * 262 *
263 *So, scan the queues of the core loops, until find non-empty. Each core 263 *So, scan the queues of the core controllers, until find non-empty. Each core
264 * has its own list that it scans. The list goes in order from closest to 264 * has its own list that it scans. The list goes in order from closest to
265 * furthest core, so it steals first from close cores. Later can add 265 * furthest core, so it steals first from close cores. Later can add
266 * taking info from the app about overlapping footprints, and scan all the 266 * taking info from the app about overlapping footprints, and scan all the
267 * others then choose work with the most footprint overlap with the contents 267 * others then choose work with the most footprint overlap with the contents
268 * of this core's cache. 268 * of this core's cache.
314 if( !haveAVictim ) return; //no work to steal, exit 314 if( !haveAVictim ) return; //no work to steal, exit
315 315
316 //have a victim core, now get the stealer-lock 316 //have a victim core, now get the stealer-lock
317 gotLock =__sync_bool_compare_and_swap( &(_VMSMasterEnv->workStealingLock), 317 gotLock =__sync_bool_compare_and_swap( &(_VMSMasterEnv->workStealingLock),
318 UNLOCKED, LOCKED ); 318 UNLOCKED, LOCKED );
319 if( !gotLock ) return; //go back to core loop, which will re-start master 319 if( !gotLock ) return; //go back to core controller, which will re-start master
320 320
321 321
322 //====== Start Gate-protection ======= 322 //====== Start Gate-protection =======
323 vicGate->gateClosed = TRUE; 323 vicGate->gateClosed = TRUE;
324 coreMightBeInProtected= vicGate->preGateProgress != vicGate->exitProgress; 324 coreMightBeInProtected= vicGate->preGateProgress != vicGate->exitProgress;