[ltt-dev] [PATCH] Fixing bugs in cluster synchronisation for accuracy algorithm

Masoume Jabbarifar masoume.jabbarifar at polymtl.ca
Mon Sep 13 17:22:59 EDT 2010


Quoting Mathieu Desnoyers <compudj at krystal.dyndns.org>:

> * masoume.jabbarifar at polymtl.ca (masoume.jabbarifar at polymtl.ca) wrote:
> > From: Masoume Jabbarifar <masoume.jabbarifar at polymtl.ca>
> >
>
> Can you document the change in the patch header ?

Once we had indirect path to reference node (more than 2 hops to root node in
the tree) the recursive function did not work so this patch fixed it. Also a
field has been added to save each accuracy for each node based on reference
node.

>
> Also, please CC Benjamin on these changes. I'd like him to have a look
> at them if he has time.
>
> > ---
> >  lttv/lttv/sync/data_structures.h           |    2 +-
> >  lttv/lttv/sync/factor_reduction_accuracy.c |   15 ++++++++++++---
> >  lttv/lttv/sync/sync_chain_lttv.c           |   18 ++++++++++++------
> >  lttv/lttv/sync/sync_chain_unittest.c       |    9 ++++++---
> >  4 files changed, 31 insertions(+), 13 deletions(-)
> >
> > diff --git a/lttv/lttv/sync/data_structures.h
> b/lttv/lttv/sync/data_structures.h
> > index 627286c..2206455 100644
> > --- a/lttv/lttv/sync/data_structures.h
> > +++ b/lttv/lttv/sync/data_structures.h
> > @@ -131,7 +131,7 @@ typedef struct
> >   * synchronization */
> >  typedef struct
> >  {
> > -	double drift, offset;
> > +	double drift, offset, accuracyToRefNode;
>
> Hrm, I see that the sync code use a different coding style than the rest
> of lttv. *sight* OK then.
>
> For your information, the rest of lttv uses lower cases for variable
> identifiers, and UpperCase for type identifiers. It also uses
> lower_case_with_underscore() for function names.
>
> >  } Factors;
> >
> >  // Correction factors between trace pairs, to be used for reduction
> > diff --git a/lttv/lttv/sync/factor_reduction_accuracy.c
> b/lttv/lttv/sync/factor_reduction_accuracy.c
> > index a63dae7..bf0546b 100644
> > --- a/lttv/lttv/sync/factor_reduction_accuracy.c
> > +++ b/lttv/lttv/sync/factor_reduction_accuracy.c
> > @@ -415,12 +415,19 @@ static void getFactors(AllFactors* const allFactors,
> unsigned int** const
> >  	unsigned int reference;
> >  	PairFactors** const pairFactors= allFactors->pairFactors;
> >
> > -	reference= references[traceNum];
> > -
> > +	if (traceNum == references[traceNum])
> > +	{
> > +		reference=traceNum;
> > +	}
> > +	else
> > +	{
> > +		reference = predecessors[references[traceNum]][traceNum];
> > +	}
> >  	if (reference == traceNum)
> >  	{
> >  		factors->offset= 0.;
> >  		factors->drift= 1.;
> > +		factors->accuracyToRefNode= 0.;
> >  	}
> >  	else
> >  	{
> > @@ -428,6 +435,8 @@ static void getFactors(AllFactors* const allFactors,
> unsigned int** const
> >
> >  		getFactors(allFactors, predecessors, references,
> >  			predecessors[reference][traceNum], &previousVertexFactors);
> > +		factors->accuracyToRefNode =
> > +			pairFactors[reference][traceNum].accuracy+
> pairFactors[traceNum][reference].accuracy +
> previousVertexFactors.accuracyToRefNode;
> >
> >  		/* Convert the time from traceNum to reference;
> >  		 * pairFactors[row][col] converts the time from col to row, invert the
> > @@ -452,7 +461,7 @@ static void getFactors(AllFactors* const allFactors,
> unsigned int** const
> >  		}
> >  		else
> >  		{
> > -			g_assert_not_reached();
> > +			//g_assert_not_reached();
>
> Why commenting this ? This assertion was probably there for a reason.
> Shutting up assertions without proper comments is usually a bad
> practice, as assertions are our safety nets.

Ops, you are right, it should not be commented.
>
> >  		}
> >  	}
> >  }
> > diff --git a/lttv/lttv/sync/sync_chain_lttv.c
> b/lttv/lttv/sync/sync_chain_lttv.c
> > index 95bef44..20ed111 100644
> > --- a/lttv/lttv/sync/sync_chain_lttv.c
> > +++ b/lttv/lttv/sync/sync_chain_lttv.c
> > @@ -218,6 +218,7 @@ bool syncTraceset(LttvTracesetContext* const
> traceSetContext)
> >  	double minOffset, minDrift;
> >  	unsigned int refFreqTrace;
> >  	int retval;
> > +	double sumAccuracy;
> >
> >  	if (!optionSync.present)
> >  	{
> > @@ -370,8 +371,6 @@ bool syncTraceset(LttvTracesetContext* const
> traceSetContext)
> >  					t->drift * t->start_tsc + t->offset));
> >  	}
> >
> > -	g_array_free(factors, TRUE);
> > -
> >  	lttv_traceset_context_compute_time_span(traceSetContext,
> >  		&traceSetContext->time_span);
> >
> > @@ -395,21 +394,28 @@ bool syncTraceset(LttvTracesetContext* const
> traceSetContext)
> >  	if (!optionSyncNull.present && optionSyncStats.present)
> >  	{
> >  		printStats(syncState);
> > -
> > +		sumAccuracy = 0;
>
>   = 0.;
>
> >  		printf("Resulting synchronization factors:\n");
> >  		for (i= 0; i < syncState->traceNb; i++)
> >  		{
> >  			LttTrace* t;
> > +			Factors* traceFactors;
> >
> >  			t= traceSetContext->traces[i]->t;
> > -
> > -			printf("\ttrace %u drift= %g offset= %g (%f) start time= %ld.%09ld\n",
> > +			traceFactors= &g_array_index(factors, Factors, i);
> > +
> > +			printf("\ttrace %u drift= %g offset= %g (%f) start time= %ld.%09ld
> accuracyToRefNode= %g\n",
> >  				i, t->drift, t->offset, (double) tsc_to_uint64(t->freq_scale,
> >  					t->start_freq, t->offset) / NANOSECONDS_PER_SECOND,
> >  				t->start_time_from_tsc.tv_sec,
> > -				t->start_time_from_tsc.tv_nsec);
> > +				t->start_time_from_tsc.tv_nsec,traceFactors->accuracyToRefNode);
> > +			sumAccuracy += traceFactors->accuracyToRefNode;
> > +
> >  		}
> >  	}
> > +	printf("Total accuracy (0.0 is the best): %g\n",sumAccuracy);
> > +
> > +	g_array_free(factors, TRUE);
> >
> >  	syncState->processingModule->destroyProcessing(syncState);
> >  	if (syncState->matchingModule != NULL)
> > diff --git a/lttv/lttv/sync/sync_chain_unittest.c
> b/lttv/lttv/sync/sync_chain_unittest.c
> > index 40302a0..d59eb09 100644
> > --- a/lttv/lttv/sync/sync_chain_unittest.c
> > +++ b/lttv/lttv/sync/sync_chain_unittest.c
> > @@ -114,6 +114,7 @@ int main(const int argc, char* const argv[])
> >  	GString* analysisModulesNames;
> >  	GString* reductionModulesNames;
> >  	unsigned int id;
> > +	double sumAccuracy;
> >  	AllFactors* allFactors;
> >
> >  	/*
> > @@ -266,15 +267,17 @@ int main(const int argc, char* const argv[])
> >  		unsigned int i;
> >
> >  		printStats(syncState);
> > -
> > +		sumAccuracy = 0;
>
>  = 0.;
>
> Thanks,
>
> Mathieu
>
> >  		printf("Resulting synchronization factors:\n");
> >  		for (i= 0; i < factors->len; i++)
> >  		{
> >  			Factors* traceFactors= &g_array_index(factors, Factors, i);
> > -			printf("\ttrace %u drift= %g offset= %g\n", i,
> > -				traceFactors->drift, traceFactors->offset);
> > +			printf("\ttrace %u drift= %g offset= %g accuracyToRefNode= %g\n", i,
> > +				traceFactors->drift, traceFactors->offset,
> traceFactors->accuracyToRefNode);
> > +			sumAccuracy += traceFactors->accuracyToRefNode;
> >  		}
> >  	}
> > +	printf("Total accuracy (0.0 is the best): %g\n",sumAccuracy);
> >
> >  	// Destroy modules and clean up
> >  	syncState->processingModule->destroyProcessing(syncState);
> > --
> > 1.6.0.4
> >
> >
> > _______________________________________________
> > ltt-dev mailing list
> > ltt-dev at lists.casi.polymtl.ca
> > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> >
>
> --
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
>







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