From 195d58693a38491e3339cf66c6ff1ae507c9df1e Mon Sep 17 00:00:00 2001
From: Marc Howison <mhowison@lbl.gov>
Date: Thu, 10 Sep 2009 04:45:48 +0000
Subject: [PATCH] added throttling for reading

---
 src/H5MultiBlock.c | 52 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 47 insertions(+), 5 deletions(-)

diff --git a/src/H5MultiBlock.c b/src/H5MultiBlock.c
index 7d57c63..afc0268 100644
--- a/src/H5MultiBlock.c
+++ b/src/H5MultiBlock.c
@@ -890,6 +890,30 @@ _H5MultiBlock_read_data (
 	herr = _H5Block_select_hyperslab_for_reading ( f, dataset_id );
 	if ( herr < 0 ) return herr;
 
+#if H5PART_THROTTLE > 0
+	int ret;
+	int token = 1;
+	if (f->myproc == 0) {
+		_H5Part_print_info ("Using throttled reads with factor = %d",
+			H5PART_THROTTLE);
+	}
+	if (f->myproc % H5PART_THROTTLE > 0) {
+		_H5Part_print_debug_detail (
+			"[%d] Waiting on read token from %d",
+			f->myproc, f->myproc - 1);
+		// wait to receive token before continuing with write
+		ret = MPI_Recv(
+			&token, 1, MPI_INT,
+			f->myproc - 1, // receive from previous proc
+			f->myproc, // use this proc id as message tag
+			f->comm,
+			MPI_STATUS_IGNORE
+			);
+		if ( ret != MPI_SUCCESS ) return HANDLE_MPI_SENDRECV_ERR;
+	}
+	_H5Part_print_debug_detail ("[%d] Executing read", f->myproc);
+#endif
+
 	herr = H5Dread ( 
 		dataset_id,
 		type,
@@ -899,6 +923,24 @@ _H5MultiBlock_read_data (
 		*data );
 	if ( herr < 0 ) return HANDLE_H5D_READ_ERR ( field_name, f->timestep );
 
+#if H5PART_THROTTLE > 0
+	if (f->myproc % H5PART_THROTTLE < H5PART_THROTTLE - 1) {
+		// pass token to next proc 
+		if (f->myproc + 1 < f->nprocs) {
+			_H5Part_print_debug_detail (
+				"[%d] Passing read token to %d",
+				f->myproc, f->myproc + 1);
+			ret = MPI_Send(
+				&token, 1, MPI_INT,
+				f->myproc + 1, // send to next proc
+				f->myproc + 1, // use the id of the target as tag
+				f->comm
+				);
+		}
+		if ( ret != MPI_SUCCESS ) return HANDLE_MPI_SENDRECV_ERR;
+	}
+#endif
+
 	herr = H5Dclose ( dataset_id );
 	if ( herr < 0 ) return HANDLE_H5D_CLOSE_ERR;
 
@@ -998,14 +1040,14 @@ _H5MultiBlock_write_data (
 #endif
 	if ( dataset < 0 ) return HANDLE_H5D_CREATE_ERR ( name, f->timestep );
 
-#if H5PART_THROTTLE_WRITES > 0
+#if H5PART_THROTTLE > 0
 	int ret;
 	int token = 1;
 	if (f->myproc == 0) {
 		_H5Part_print_info ("Using throttled writes with factor = %d",
-			H5PART_THROTTLE_WRITES);
+			H5PART_THROTTLE);
 	}
-	if (f->myproc % H5PART_THROTTLE_WRITES > 0) {
+	if (f->myproc % H5PART_THROTTLE > 0) {
 		_H5Part_print_debug_detail (
 			"[%d] Waiting on write token from %d",
 			f->myproc, f->myproc - 1);
@@ -1031,8 +1073,8 @@ _H5MultiBlock_write_data (
 		data );
 	if ( herr < 0 ) return HANDLE_H5D_WRITE_ERR ( name, f->timestep );
 
-#if H5PART_THROTTLE_WRITES > 0
-	if (f->myproc % H5PART_THROTTLE_WRITES < H5PART_THROTTLE_WRITES - 1) {
+#if H5PART_THROTTLE > 0
+	if (f->myproc % H5PART_THROTTLE < H5PART_THROTTLE - 1) {
 		// pass token to next proc 
 		if (f->myproc + 1 < f->nprocs) {
 			_H5Part_print_debug_detail (