Collect JIT instrumentation from workers.

Previously, when using parallel query, EXPLAIN (ANALYZE)'s JIT
compilation timings did not include the overhead from doing so on the
workers.  Fix that.

We do so by simply aggregating the cost of doing JIT compilation on
workers and the leader together. Arguably that's not quite accurate,
because the total time spend doing so is spent in parallel - but it's
hard to do much better.  For additional detail, when VERBOSE is
specified, the stats for workers are displayed separately.

Author: Amit Khandekar and Andres Freund
Discussion: https://postgr.es/m/CAJ3gD9eLrz51RK_gTkod+71iDcjpB_N8eC6vU2AW-VicsAERpQ@mail.gmail.com
Backpatch: 11-

6 files changed, 176 insertions, 36 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 01520154e48..ed6afe79a9f 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -563,9 +563,9 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 	 * depending on build options.  Might want to separate that out from COSTS
 	 * at a later stage.
 	 */
-	if (queryDesc->estate->es_jit && es->costs &&
-		queryDesc->estate->es_jit->created_functions > 0)
-		ExplainPrintJIT(es, queryDesc);
+	if (es->costs)
+		ExplainPrintJIT(es, queryDesc->estate->es_jit_flags,
+						queryDesc->estate->es_jit_combined_instr, -1);
 
 	/*
 	 * Close down the query and free resources.  Include time for this in the
@@ -691,19 +691,27 @@ ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc)
 /*
  * ExplainPrintJIT -
  *	  Append information about JITing to es->str.
+ *
+ * Can be used to print the JIT instrumentation of the backend (worker_num =
+ * -1) or that of a specific worker (worker_num = ...).
  */
 void
-ExplainPrintJIT(ExplainState *es, QueryDesc *queryDesc)
+ExplainPrintJIT(ExplainState *es, int jit_flags,
+				JitInstrumentation *ji, int worker_num)
 {
-	JitContext *jc = queryDesc->estate->es_jit;
 	instr_time	total_time;
+	bool		for_workers = (worker_num >= 0);
+
+	/* don't print information if no JITing happened */
+	if (!ji || ji->created_functions == 0)
+		return;
 
 	/* calculate total time */
 	INSTR_TIME_SET_ZERO(total_time);
-	INSTR_TIME_ADD(total_time, jc->generation_counter);
-	INSTR_TIME_ADD(total_time, jc->inlining_counter);
-	INSTR_TIME_ADD(total_time, jc->optimization_counter);
-	INSTR_TIME_ADD(total_time, jc->emission_counter);
+	INSTR_TIME_ADD(total_time, ji->generation_counter);
+	INSTR_TIME_ADD(total_time, ji->inlining_counter);
+	INSTR_TIME_ADD(total_time, ji->optimization_counter);
+	INSTR_TIME_ADD(total_time, ji->emission_counter);
 
 	ExplainOpenGroup("JIT", "JIT", true, es);
 
@@ -711,27 +719,30 @@ ExplainPrintJIT(ExplainState *es, QueryDesc *queryDesc)
 	if (es->format == EXPLAIN_FORMAT_TEXT)
 	{
 		appendStringInfoSpaces(es->str, es->indent * 2);
-		appendStringInfo(es->str, "JIT:\n");
+		if (for_workers)
+			appendStringInfo(es->str, "JIT for worker %u:\n", worker_num);
+		else
+			appendStringInfo(es->str, "JIT:\n");
 		es->indent += 1;
 
-		ExplainPropertyInteger("Functions", NULL, jc->created_functions, es);
+		ExplainPropertyInteger("Functions", NULL, ji->created_functions, es);
 
 		appendStringInfoSpaces(es->str, es->indent * 2);
 		appendStringInfo(es->str, "Options: %s %s, %s %s, %s %s, %s %s\n",
-						 "Inlining", jc->flags & PGJIT_INLINE ? "true" : "false",
-						 "Optimization", jc->flags & PGJIT_OPT3 ? "true" : "false",
-						 "Expressions", jc->flags & PGJIT_EXPR ? "true" : "false",
-						 "Deforming", jc->flags & PGJIT_DEFORM ? "true" : "false");
+						 "Inlining", jit_flags & PGJIT_INLINE ? "true" : "false",
+						 "Optimization", jit_flags & PGJIT_OPT3 ? "true" : "false",
+						 "Expressions", jit_flags & PGJIT_EXPR ? "true" : "false",
+						 "Deforming", jit_flags & PGJIT_DEFORM ? "true" : "false");
 
 		if (es->analyze && es->timing)
 		{
 			appendStringInfoSpaces(es->str, es->indent * 2);
 			appendStringInfo(es->str,
 							 "Timing: %s %.3f ms, %s %.3f ms, %s %.3f ms, %s %.3f ms, %s %.3f ms\n",
-							 "Generation", 1000.0 * INSTR_TIME_GET_DOUBLE(jc->generation_counter),
-							 "Inlining", 1000.0 * INSTR_TIME_GET_DOUBLE(jc->inlining_counter),
-							 "Optimization", 1000.0 * INSTR_TIME_GET_DOUBLE(jc->optimization_counter),
-							 "Emission", 1000.0 * INSTR_TIME_GET_DOUBLE(jc->emission_counter),
+							 "Generation", 1000.0 * INSTR_TIME_GET_DOUBLE(ji->generation_counter),
+							 "Inlining", 1000.0 * INSTR_TIME_GET_DOUBLE(ji->inlining_counter),
+							 "Optimization", 1000.0 * INSTR_TIME_GET_DOUBLE(ji->optimization_counter),
+							 "Emission", 1000.0 * INSTR_TIME_GET_DOUBLE(ji->emission_counter),
 							 "Total", 1000.0 * INSTR_TIME_GET_DOUBLE(total_time));
 		}
 
@@ -739,13 +750,14 @@ ExplainPrintJIT(ExplainState *es, QueryDesc *queryDesc)
 	}
 	else
 	{
-		ExplainPropertyInteger("Functions", NULL, jc->created_functions, es);
+		ExplainPropertyInteger("Worker Number", NULL, worker_num, es);
+		ExplainPropertyInteger("Functions", NULL, ji->created_functions, es);
 
 		ExplainOpenGroup("Options", "Options", true, es);
-		ExplainPropertyBool("Inlining", jc->flags & PGJIT_INLINE, es);
-		ExplainPropertyBool("Optimization", jc->flags & PGJIT_OPT3, es);
-		ExplainPropertyBool("Expressions", jc->flags & PGJIT_EXPR, es);
-		ExplainPropertyBool("Deforming", jc->flags & PGJIT_DEFORM, es);
+		ExplainPropertyBool("Inlining", jit_flags & PGJIT_INLINE, es);
+		ExplainPropertyBool("Optimization", jit_flags & PGJIT_OPT3, es);
+		ExplainPropertyBool("Expressions", jit_flags & PGJIT_EXPR, es);
+		ExplainPropertyBool("Deforming", jit_flags & PGJIT_DEFORM, es);
 		ExplainCloseGroup("Options", "Options", true, es);
 
 		if (es->analyze && es->timing)
@@ -753,16 +765,16 @@ ExplainPrintJIT(ExplainState *es, QueryDesc *queryDesc)
 			ExplainOpenGroup("Timing", "Timing", true, es);
 
 			ExplainPropertyFloat("Generation", "ms",
-								 1000.0 * INSTR_TIME_GET_DOUBLE(jc->generation_counter),
+								 1000.0 * INSTR_TIME_GET_DOUBLE(ji->generation_counter),
 								 3, es);
 			ExplainPropertyFloat("Inlining", "ms",
-								 1000.0 * INSTR_TIME_GET_DOUBLE(jc->inlining_counter),
+								 1000.0 * INSTR_TIME_GET_DOUBLE(ji->inlining_counter),
 								 3, es);
 			ExplainPropertyFloat("Optimization", "ms",
-								 1000.0 * INSTR_TIME_GET_DOUBLE(jc->optimization_counter),
+								 1000.0 * INSTR_TIME_GET_DOUBLE(ji->optimization_counter),
 								 3, es);
 			ExplainPropertyFloat("Emission", "ms",
-								 1000.0 * INSTR_TIME_GET_DOUBLE(jc->emission_counter),
+								 1000.0 * INSTR_TIME_GET_DOUBLE(ji->emission_counter),
 								 3, es);
 			ExplainPropertyFloat("Total", "ms",
 								 1000.0 * INSTR_TIME_GET_DOUBLE(total_time),
@@ -1554,6 +1566,25 @@ ExplainNode(PlanState *planstate, List *ancestors,
 					ExplainPropertyInteger("Workers Launched", NULL,
 										   nworkers, es);
 				}
+
+				/*
+				 * Print per-worker Jit instrumentation. Use same conditions
+				 * as for the leader's JIT instrumentation, see comment there.
+				 */
+				if (es->costs && es->verbose &&
+					outerPlanState(planstate)->worker_jit_instrument)
+				{
+					PlanState *child = outerPlanState(planstate);
+					int			n;
+					SharedJitInstrumentation *w = child->worker_jit_instrument;
+
+					for (n = 0; n < w->num_workers; ++n)
+					{
+						ExplainPrintJIT(es, child->state->es_jit_flags,
+										&w->jit_instr[n], n);
+					}
+				}
+
 				if (gather->single_copy || es->format != EXPLAIN_FORMAT_TEXT)
 					ExplainPropertyBool("Single Copy", gather->single_copy, es);
 			}
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 85d980356b7..04f14c91787 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -48,6 +48,7 @@
 #include "executor/execdebug.h"
 #include "executor/nodeSubplan.h"
 #include "foreign/fdwapi.h"
+#include "jit/jit.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "optimizer/clauses.h"
@@ -494,6 +495,21 @@ standard_ExecutorEnd(QueryDesc *queryDesc)
 
 	ExecEndPlan(queryDesc->planstate, estate);
 
+	/*
+	 * If this process has done JIT, either merge stats into worker stats, or
+	 * use this process' stats as the global stats if no parallelism was used
+	 * / no workers did JIT.
+	 */
+	if (estate->es_instrument && queryDesc->estate->es_jit)
+	{
+		if (queryDesc->estate->es_jit_combined_instr)
+			InstrJitAgg(queryDesc->estate->es_jit_combined_instr,
+						&queryDesc->estate->es_jit->instr);
+		else
+			queryDesc->estate->es_jit_combined_instr =
+				&queryDesc->estate->es_jit->instr;
+	}
+
 	/* do away with our snapshots */
 	UnregisterSnapshot(estate->es_snapshot);
 	UnregisterSnapshot(estate->es_crosscheck_snapshot);
diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c
index c93084e4d2a..838ec842991 100644
--- a/src/backend/executor/execParallel.c
+++ b/src/backend/executor/execParallel.c
@@ -37,6 +37,7 @@
 #include "executor/nodeSort.h"
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
+#include "jit/jit.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/planmain.h"
 #include "optimizer/planner.h"
@@ -62,6 +63,7 @@
 #define PARALLEL_KEY_INSTRUMENTATION	UINT64CONST(0xE000000000000006)
 #define PARALLEL_KEY_DSA				UINT64CONST(0xE000000000000007)
 #define PARALLEL_KEY_QUERY_TEXT		UINT64CONST(0xE000000000000008)
+#define PARALLEL_KEY_JIT_INSTRUMENTATION UINT64CONST(0xE000000000000009)
 
 #define PARALLEL_TUPLE_QUEUE_SIZE		65536
 
@@ -573,9 +575,11 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate,
 	char	   *paramlistinfo_space;
 	BufferUsage *bufusage_space;
 	SharedExecutorInstrumentation *instrumentation = NULL;
+	SharedJitInstrumentation *jit_instrumentation = NULL;
 	int			pstmt_len;
 	int			paramlistinfo_len;
 	int			instrumentation_len = 0;
+	int			jit_instrumentation_len = 0;
 	int			instrument_offset = 0;
 	Size		dsa_minsize = dsa_minimum_size();
 	char	   *query_string;
@@ -669,6 +673,16 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate,
 					 mul_size(e.nnodes, nworkers));
 		shm_toc_estimate_chunk(&pcxt->estimator, instrumentation_len);
 		shm_toc_estimate_keys(&pcxt->estimator, 1);
+
+		/* Estimate space for JIT instrumentation, if required. */
+		if (estate->es_jit_flags != PGJIT_NONE)
+		{
+			jit_instrumentation_len =
+				offsetof(SharedJitInstrumentation, jit_instr) +
+				sizeof(JitInstrumentation) * nworkers;
+			shm_toc_estimate_chunk(&pcxt->estimator, jit_instrumentation_len);
+			shm_toc_estimate_keys(&pcxt->estimator, 1);
+		}
 	}
 
 	/* Estimate space for DSA area. */
@@ -742,6 +756,18 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate,
 		shm_toc_insert(pcxt->toc, PARALLEL_KEY_INSTRUMENTATION,
 					   instrumentation);
 		pei->instrumentation = instrumentation;
+
+		if (estate->es_jit_flags != PGJIT_NONE)
+		{
+			jit_instrumentation = shm_toc_allocate(pcxt->toc,
+												   jit_instrumentation_len);
+			jit_instrumentation->num_workers = nworkers;
+			memset(jit_instrumentation->jit_instr, 0,
+				   sizeof(JitInstrumentation) * nworkers);
+			shm_toc_insert(pcxt->toc, PARALLEL_KEY_JIT_INSTRUMENTATION,
+						   jit_instrumentation);
+			pei->jit_instrumentation = jit_instrumentation;
+		}
 	}
 
 	/*
@@ -1004,6 +1030,46 @@ ExecParallelRetrieveInstrumentation(PlanState *planstate,
 }
 
 /*
+ * Add up the workers' JIT instrumentation from dynamic shared memory.
+ */
+static void
+ExecParallelRetrieveJitInstrumentation(PlanState *planstate,
+									   SharedJitInstrumentation *shared_jit)
+{
+	JitInstrumentation *combined;
+	int			ibytes;
+
+	int			n;
+
+	/*
+	 * Accumulate worker JIT instrumentation into the combined JIT
+	 * instrumentation, allocating it if required. Note this is kept separate
+	 * from the leader's own instrumentation.
+	 */
+	if (!planstate->state->es_jit_combined_instr)
+		planstate->state->es_jit_combined_instr =
+			MemoryContextAllocZero(planstate->state->es_query_cxt, sizeof(JitInstrumentation));
+	combined = planstate->state->es_jit_combined_instr;
+
+	/* Accummulate all the workers' instrumentations. */
+	for (n = 0; n < shared_jit->num_workers; ++n)
+		InstrJitAgg(combined, &shared_jit->jit_instr[n]);
+
+	/*
+	 * Store the per-worker detail.
+	 *
+	 * Similar to ExecParallelRetrieveInstrumentation(), allocate the
+	 * instrumentation in per-query context.
+	 */
+	ibytes = offsetof(SharedJitInstrumentation, jit_instr)
+			 + mul_size(shared_jit->num_workers, sizeof(JitInstrumentation));
+	planstate->worker_jit_instrument =
+		MemoryContextAlloc(planstate->state->es_query_cxt, ibytes);
+
+	memcpy(planstate->worker_jit_instrument, shared_jit, ibytes);
+}
+
+/*
  * Finish parallel execution.  We wait for parallel workers to finish, and
  * accumulate their buffer usage.
  */
@@ -1068,6 +1134,11 @@ ExecParallelCleanup(ParallelExecutorInfo *pei)
 		ExecParallelRetrieveInstrumentation(pei->planstate,
 											pei->instrumentation);
 
+	/* Accumulate JIT instrumentation, if any. */
+	if (pei->jit_instrumentation)
+		ExecParallelRetrieveJitInstrumentation(pei->planstate,
+											pei->jit_instrumentation);
+
 	/* Free any serialized parameters. */
 	if (DsaPointerIsValid(pei->param_exec))
 	{
@@ -1274,6 +1345,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 	DestReceiver *receiver;
 	QueryDesc  *queryDesc;
 	SharedExecutorInstrumentation *instrumentation;
+	SharedJitInstrumentation *jit_instrumentation;
 	int			instrument_options = 0;
 	void	   *area_space;
 	dsa_area   *area;
@@ -1287,6 +1359,8 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 	instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_INSTRUMENTATION, true);
 	if (instrumentation != NULL)
 		instrument_options = instrumentation->instrument_options;
+	jit_instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_JIT_INSTRUMENTATION,
+										 true);
 	queryDesc = ExecParallelGetQueryDesc(toc, receiver, instrument_options);
 
 	/* Setting debug_query_string for individual workers */
@@ -1350,6 +1424,14 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 		ExecParallelReportInstrumentation(queryDesc->planstate,
 										  instrumentation);
 
+	/* Report JIT instrumentation data if any */
+	if (queryDesc->estate->es_jit && jit_instrumentation != NULL)
+	{
+		Assert(ParallelWorkerNumber < jit_instrumentation->num_workers);
+		jit_instrumentation->jit_instr[ParallelWorkerNumber] =
+			queryDesc->estate->es_jit->instr;
+	}
+
 	/* Must do this after capturing instrumentation. */
 	ExecutorEnd(queryDesc);
 
diff --git a/src/backend/jit/jit.c b/src/backend/jit/jit.c
index 7d3883d3bf4..5d1f2e57be1 100644
--- a/src/backend/jit/jit.c
+++ b/src/backend/jit/jit.c
@@ -182,6 +182,17 @@ jit_compile_expr(struct ExprState *state)
 	return false;
 }
 
+/* Aggregate JIT instrumentation information */
+void
+InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add)
+{
+	dst->created_functions += add->created_functions;
+	INSTR_TIME_ADD(dst->generation_counter, add->generation_counter);
+	INSTR_TIME_ADD(dst->inlining_counter, add->inlining_counter);
+	INSTR_TIME_ADD(dst->optimization_counter, add->optimization_counter);
+	INSTR_TIME_ADD(dst->emission_counter, add->emission_counter);
+}
+
 static bool
 file_exists(const char *name)
 {
diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c
index 640c27fc408..7510698f863 100644
--- a/src/backend/jit/llvm/llvmjit.c
+++ b/src/backend/jit/llvm/llvmjit.c
@@ -224,7 +224,7 @@ llvm_expand_funcname(struct LLVMJitContext *context, const char *basename)
 {
 	Assert(context->module != NULL);
 
-	context->base.created_functions++;
+	context->base.instr.created_functions++;
 
 	/*
 	 * Previously we used dots to separate, but turns out some tools, e.g.
@@ -504,7 +504,7 @@ llvm_compile_module(LLVMJitContext *context)
 		INSTR_TIME_SET_CURRENT(starttime);
 		llvm_inline(context->module);
 		INSTR_TIME_SET_CURRENT(endtime);
-		INSTR_TIME_ACCUM_DIFF(context->base.inlining_counter,
+		INSTR_TIME_ACCUM_DIFF(context->base.instr.inlining_counter,
 							  endtime, starttime);
 	}
 
@@ -524,7 +524,7 @@ llvm_compile_module(LLVMJitContext *context)
 	INSTR_TIME_SET_CURRENT(starttime);
 	llvm_optimize_module(context, context->module);
 	INSTR_TIME_SET_CURRENT(endtime);
-	INSTR_TIME_ACCUM_DIFF(context->base.optimization_counter,
+	INSTR_TIME_ACCUM_DIFF(context->base.instr.optimization_counter,
 						  endtime, starttime);
 
 	if (jit_dump_bitcode)
@@ -575,7 +575,7 @@ llvm_compile_module(LLVMJitContext *context)
 	}
 #endif
 	INSTR_TIME_SET_CURRENT(endtime);
-	INSTR_TIME_ACCUM_DIFF(context->base.emission_counter,
+	INSTR_TIME_ACCUM_DIFF(context->base.instr.emission_counter,
 						  endtime, starttime);
 
 	context->module = NULL;
@@ -596,9 +596,9 @@ llvm_compile_module(LLVMJitContext *context)
 
 	ereport(DEBUG1,
 			(errmsg("time to inline: %.3fs, opt: %.3fs, emit: %.3fs",
-					INSTR_TIME_GET_DOUBLE(context->base.inlining_counter),
-					INSTR_TIME_GET_DOUBLE(context->base.optimization_counter),
-					INSTR_TIME_GET_DOUBLE(context->base.emission_counter)),
+					INSTR_TIME_GET_DOUBLE(context->base.instr.inlining_counter),
+					INSTR_TIME_GET_DOUBLE(context->base.instr.optimization_counter),
+					INSTR_TIME_GET_DOUBLE(context->base.instr.emission_counter)),
 			 errhidestmt(true),
 			 errhidecontext(true)));
 }
diff --git a/src/backend/jit/llvm/llvmjit_expr.c b/src/backend/jit/llvm/llvmjit_expr.c
index 0f3109334e8..7454d05acaf 100644
--- a/src/backend/jit/llvm/llvmjit_expr.c
+++ b/src/backend/jit/llvm/llvmjit_expr.c
@@ -2557,7 +2557,7 @@ llvm_compile_expr(ExprState *state)
 	llvm_leave_fatal_on_oom();
 
 	INSTR_TIME_SET_CURRENT(endtime);
-	INSTR_TIME_ACCUM_DIFF(context->base.generation_counter,
+	INSTR_TIME_ACCUM_DIFF(context->base.instr.generation_counter,
 						  endtime, starttime);
 
 	return true;