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-rw-r--r--src/H5FD.c85
-rw-r--r--src/H5FDmpio.c9
-rw-r--r--src/H5FDpublic.h14
3 files changed, 68 insertions, 40 deletions
diff --git a/src/H5FD.c b/src/H5FD.c
index f77cbda..23563f8 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -2274,52 +2274,63 @@ H5FD_read(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, hsize_t si
} /* end if */
/* Current read doesn't overlap with metadata accumulator, read it into accumulator */
else {
- /* Flush current contents, if dirty */
- if(file->accum_dirty) {
- if ((file->cls->write)(file, H5FD_MEM_DEFAULT, dxpl_id, file->accum_loc, file->accum_size, file->meta_accum)<0)
- HRETURN_ERROR(H5E_VFL, H5E_WRITEERROR, FAIL, "driver write request failed");
-
- /* Reset accumulator dirty flag */
- file->accum_dirty=FALSE;
- } /* end if */
-
- /* Cache the new piece of metadata */
- /* Check if we need to resize the buffer */
- if(size>file->accum_buf_size) {
- /* Grow the metadata accumulator buffer */
- if ((file->meta_accum=H5FL_BLK_REALLOC(meta_accum,file->meta_accum,size))==NULL)
- HRETURN_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate metadata accumulator buffer");
+ /* Only update the metadata accumulator if it is not dirty or if
+ * we are allowed to write the accumulator out during reads (when
+ * it is dirty)
+ */
+ if(file->feature_flags&H5FD_FEAT_ACCUMULATE_METADATA_READ || !file->accum_dirty) {
+ /* Flush current contents, if dirty */
+ if(file->accum_dirty) {
+ if ((file->cls->write)(file, H5FD_MEM_DEFAULT, dxpl_id, file->accum_loc, file->accum_size, file->meta_accum)<0)
+ HRETURN_ERROR(H5E_VFL, H5E_WRITEERROR, FAIL, "driver write request failed");
- /* Note the new buffer size */
- file->accum_buf_size=size;
- } /* end if */
- else {
- /* Check if we should shrink the accumulator buffer */
- if(size<(file->accum_buf_size/H5FD_ACCUM_THROTTLE) &&
- file->accum_buf_size>H5FD_ACCUM_THRESHOLD) {
- hsize_t new_size=(file->accum_buf_size/H5FD_ACCUM_THROTTLE); /* New size of accumulator buffer */
+ /* Reset accumulator dirty flag */
+ file->accum_dirty=FALSE;
+ } /* end if */
- /* Shrink the accumulator buffer */
- if ((file->meta_accum=H5FL_BLK_REALLOC(meta_accum,file->meta_accum,new_size))==NULL)
+ /* Cache the new piece of metadata */
+ /* Check if we need to resize the buffer */
+ if(size>file->accum_buf_size) {
+ /* Grow the metadata accumulator buffer */
+ if ((file->meta_accum=H5FL_BLK_REALLOC(meta_accum,file->meta_accum,size))==NULL)
HRETURN_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate metadata accumulator buffer");
/* Note the new buffer size */
- file->accum_buf_size=new_size;
+ file->accum_buf_size=size;
} /* end if */
- } /* end else */
+ else {
+ /* Check if we should shrink the accumulator buffer */
+ if(size<(file->accum_buf_size/H5FD_ACCUM_THROTTLE) &&
+ file->accum_buf_size>H5FD_ACCUM_THRESHOLD) {
+ hsize_t new_size=(file->accum_buf_size/H5FD_ACCUM_THROTTLE); /* New size of accumulator buffer */
- /* Update accumulator information */
- file->accum_loc=addr;
- file->accum_size=size;
- file->accum_dirty=FALSE;
+ /* Shrink the accumulator buffer */
+ if ((file->meta_accum=H5FL_BLK_REALLOC(meta_accum,file->meta_accum,new_size))==NULL)
+ HRETURN_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate metadata accumulator buffer");
- /* Read into accumulator */
- if ((file->cls->read)(file, H5FD_MEM_DEFAULT, dxpl_id, file->accum_loc, file->accum_size, file->meta_accum)<0)
- HRETURN_ERROR(H5E_VFL, H5E_READERROR, FAIL, "driver read request failed");
+ /* Note the new buffer size */
+ file->accum_buf_size=new_size;
+ } /* end if */
+ } /* end else */
- /* Copy into buffer */
- assert(size==(hsize_t)((size_t)size)); /*check for overflow*/
- HDmemcpy(buf,file->meta_accum,(size_t)size);
+ /* Update accumulator information */
+ file->accum_loc=addr;
+ file->accum_size=size;
+ file->accum_dirty=FALSE;
+
+ /* Read into accumulator */
+ if ((file->cls->read)(file, H5FD_MEM_DEFAULT, dxpl_id, file->accum_loc, file->accum_size, file->meta_accum)<0)
+ HRETURN_ERROR(H5E_VFL, H5E_READERROR, FAIL, "driver read request failed");
+
+ /* Copy into buffer */
+ assert(size==(hsize_t)((size_t)size)); /*check for overflow*/
+ HDmemcpy(buf,file->meta_accum,(size_t)size);
+ } /* end if */
+ else {
+ /* Dispatch to driver */
+ if ((file->cls->read)(file, type, dxpl_id, addr, size, buf)<0)
+ HRETURN_ERROR(H5E_VFL, H5E_READERROR, FAIL, "driver read request failed");
+ } /* end else */
} /* end else */
} /* end if */
else {
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 6b4a20c..7992b12 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -952,6 +952,15 @@ H5FD_mpio_query(const H5FD_t *_file, unsigned long *flags /* out */)
if(flags) {
*flags=0;
*flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
+
+ /* Distinguish between updating the metadata accumulator on writes and
+ * reads. This is particularly (perhaps only, even) important for MPI-I/O
+ * where we guarantee that writes are collective, but reads may not be.
+ * If we were to allow the metadata accumulator to be written during a
+ * read operation, the application would hang.
+ */
+ *flags|=H5FD_FEAT_ACCUMULATE_METADATA_WRITE; /* OK to accumulate metadata for faster writes */
+
*flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
} /* end if */
diff --git a/src/H5FDpublic.h b/src/H5FDpublic.h
index 802b1c9..0a8ea5d 100644
--- a/src/H5FDpublic.h
+++ b/src/H5FDpublic.h
@@ -89,8 +89,16 @@ typedef enum H5FD_mem_t {
* the library will attempt to cache metadata as it is written to the file
* and build up a larger block of metadata to eventually pass to the VFL
* 'write' routine.
+ *
+ * Distinguish between updating the metadata accumulator on writes and
+ * reads. This is particularly (perhaps only, even) important for MPI-I/O
+ * where we guarantee that writes are collective, but reads may not be.
+ * If we were to allow the metadata accumulator to be written during a
+ * read operation, the application would hang.
*/
-#define H5FD_FEAT_ACCUMULATE_METADATA 0x00000002
+#define H5FD_FEAT_ACCUMULATE_METADATA_WRITE 0x00000002
+#define H5FD_FEAT_ACCUMULATE_METADATA_READ 0x00000004
+#define H5FD_FEAT_ACCUMULATE_METADATA (H5FD_FEAT_ACCUMULATE_METADATA_WRITE|H5FD_FEAT_ACCUMULATE_METADATA_READ)
/*
* Defining the H5FD_FEAT_DATA_SIEVE for a VFL driver means that
* the library will attempt to cache raw data as it is read from/written to
@@ -98,13 +106,13 @@ typedef enum H5FD_mem_t {
* http://www.mcs.anl.gov/~thakur/papers/romio-coll.ps.gz
* http://www.mcs.anl.gov/~thakur/papers/mpio-high-perf.ps.gz
*/
-#define H5FD_FEAT_DATA_SIEVE 0x00000004
+#define H5FD_FEAT_DATA_SIEVE 0x00000008
/*
* Defining the H5FD_FEAT_AGGREGATE_SMALLDATA for a VFL driver means that
* the library will attempt to allocate a larger block for "small" raw data
* and then sub-allocate "small" raw data requests from that larger block.
*/
-#define H5FD_FEAT_AGGREGATE_SMALLDATA 0x00000008
+#define H5FD_FEAT_AGGREGATE_SMALLDATA 0x00000010
/* Forward declaration */
generated by cgit v0.12 at 2024-11-02 08:20:53 (GMT)