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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Copyright by The HDF Group. *
* Copyright by the Board of Trustees of the University of Illinois. *
* All rights reserved. *
* *
* This file is part of HDF5. The full HDF5 copyright notice, including *
* terms governing use, modification, and redistribution, is contained in *
* the files COPYING and Copyright.html. COPYING can be found at the root *
* of the source code distribution tree; Copyright.html can be found at the *
* root level of an installed copy of the electronic HDF5 document set and *
* is linked from the top-level documents page. It can also be found at *
* http://hdfgroup.org/HDF5/doc/Copyright.html. If you do not have *
* access to either file, you may request a copy from help@hdfgroup.org. *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
* Programmer: John Mainzer -- 4/19/06
*
* Purpose: This file contains declarations which are normally visible
* only within the H5AC package (just H5AC.c at present).
*
* Source files outside the H5AC package should include
* H5ACprivate.h instead.
*
* The one exception to this rule is testpar/t_cache.c. The
* test code is easier to write if it can look at H5AC_aux_t.
* Indeed, this is the main reason why this file was created.
*
*/
#ifndef H5AC_PACKAGE
#error "Do not include this file outside the H5AC package!"
#endif
#ifndef _H5ACpkg_H
#define _H5ACpkg_H
/* Get package's private header */
#include "H5ACprivate.h" /* Metadata cache */
/* Get needed headers */
#include "H5Cprivate.h" /* Cache */
#include "H5SLprivate.h" /* Skip lists */
#define H5AC_DEBUG_DIRTY_BYTES_CREATION 0
#ifdef H5_HAVE_PARALLEL
/* the following #defined are used to specify the operation required
* at a sync point.
*/
#define H5AC_SYNC_POINT_OP__FLUSH_TO_MIN_CLEAN 0
#define H5AC_SYNC_POINT_OP__FLUSH_CACHE 1
#endif /* H5_HAVE_PARALLEL */
/*-------------------------------------------------------------------------
* It is a bit difficult to set ranges of allowable values on the
* dirty_bytes_threshold field of H5AC_aux_t. The following are
* probably broader than they should be.
*-------------------------------------------------------------------------
*/
#define H5AC__MIN_DIRTY_BYTES_THRESHOLD (size_t) \
(H5C__MIN_MAX_CACHE_SIZE / 2)
#define H5AC__DEFAULT_DIRTY_BYTES_THRESHOLD (256 * 1024)
#define H5AC__MAX_DIRTY_BYTES_THRESHOLD (size_t) \
(H5C__MAX_MAX_CACHE_SIZE / 4)
/****************************************************************************
*
* structure H5AC_aux_t
*
* While H5AC has become a wrapper for the cache implemented in H5C.c, there
* are some features of the metadata cache that are specific to it, and which
* therefore do not belong in the more generic H5C cache code.
*
* In particular, there is the matter of synchronizing writes from the
* metadata cache to disk in the PHDF5 case.
*
* Prior to this update, the presumption was that all metadata caches would
* write the same data at the same time since all operations modifying
* metadata must be performed collectively. Given this assumption, it was
* safe to allow only the writes from process 0 to actually make it to disk,
* while metadata writes from all other processes were discarded.
*
* Unfortunately, this presumption is in error as operations that read
* metadata need not be collective, but can change the location of dirty
* entries in the metadata cache LRU lists. This can result in the same
* metadata write operation triggering writes from the metadata caches on
* some processes, but not all (causing a hang), or in different sets of
* entries being written from different caches (potentially resulting in
* metadata corruption in the file).
*
* To deal with this issue, I decided to apply a paradigm shift to the way
* metadata is written to disk.
*
* With this set of changes, only the metadata cache on process 0 is able
* to write metadata to disk, although metadata caches on all other
* processes can read metadata from disk as before.
*
* To keep all the other caches from getting plugged up with dirty metadata,
* process 0 periodically broadcasts a list of entries that it has flushed
* since that last notice, and which are currently clean. The other caches
* mark these entries as clean as well, which allows them to evict the
* entries as needed.
*
* One obvious problem in this approach is synchronizing the broadcasts
* and receptions, as different caches may see different amounts of
* activity.
*
* The current solution is for the caches to track the number of bytes
* of newly generated dirty metadata, and to broadcast and receive
* whenever this value exceeds some user specified threshold.
*
* Maintaining this count is easy for all processes not on process 0 --
* all that is necessary is to add the size of the entry to the total
* whenever there is an insertion, a move of a previously clean entry,
* or whever a previously clean entry is marked dirty in an unprotect.
*
* On process 0, we have to be careful not to count dirty bytes twice.
* If an entry is marked dirty, flushed, and marked dirty again, all
* within a single reporting period, it only th first marking should
* be added to the dirty bytes generated tally, as that is all that
* the other processes will see.
*
* At present, this structure exists to maintain the fields needed to
* implement the above scheme, and thus is only used in the parallel
* case. However, other uses may arise in the future.
*
* Instance of this structure are associated with metadata caches via
* the aux_ptr field of H5C_t (see H5Cpkg.h). The H5AC code is
* responsible for allocating, maintaining, and discarding instances
* of H5AC_aux_t.
*
* The remainder of this header comments documents the individual fields
* of the structure.
*
* JRM - 6/27/05
*
* Update: When the above was written, I planned to allow the process
* 0 metadata cache to write dirty metadata between sync points.
* However, testing indicated that this allowed occasional
* messages from the future to reach the caches on other processes.
*
* To resolve this, the code was altered to require that all metadata
* writes take place during sync points -- which solved the problem.
* Initially all writes were performed by the process 0 cache. This
* approach was later replaced with a distributed write approach
* in which each process writes a subset of the metadata to be
* written.
*
* After thinking on the matter for a while, I arrived at the
* conclusion that the process 0 cache could be allowed to write
* dirty metadata between sync points if it restricted itself to
* entries that had been dirty at the time of the previous sync point.
*
* To date, there has been no attempt to implement this optimization.
* However, should it be attempted, much of the supporting code
* should still be around.
*
* JRM -- 1/6/15
*
* magic: Unsigned 32 bit integer always set to
* H5AC__H5AC_AUX_T_MAGIC. This field is used to validate
* pointers to instances of H5AC_aux_t.
*
* mpi_comm: MPI communicator associated with the file for which the
* cache has been created.
*
* mpi_rank: MPI rank of this process within mpi_comm.
*
* mpi_size: Number of processes in mpi_comm.
*
* write_permitted: Boolean flag used to control whether the cache
* is permitted to write to file.
*
* dirty_bytes_threshold: Integer field containing the dirty bytes
* generation threashold. Whenever dirty byte creation
* exceeds this value, the metadata cache on process 0
* broadcasts a list of the entries it has flushed since
* the last broadcast (or since the beginning of execution)
* and which are currently clean (if they are still in the
* cache)
*
* Similarly, metadata caches on processes other than process
* 0 will attempt to receive a list of clean entries whenever
* the threshold is exceeded.
*
* dirty_bytes: Integer field containing the number of bytes of dirty
* metadata generated since the beginning of the computation,
* or (more typically) since the last clean entries list
* broadcast. This field is reset to zero after each such
* broadcast.
*
* metadata_write_strategy: Integer code indicating how we will be
* writing the metadata. In the first incarnation of
* this code, all writes were done from process 0. This
* field exists to facilitate experiments with other
* strategies.
*
* At present, this field must be set to either
* H5AC_METADATA_WRITE_STRATEGY__PROCESS_0_ONLY or
* H5AC_METADATA_WRITE_STRATEGY__DISTRIBUTED.
*
* dirty_bytes_propagations: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of times the cleaned list
* has been propagated from process 0 to the other
* processes.
*
* unprotect_dirty_bytes: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of dirty bytes created
* via unprotect operations since the last time the cleaned
* list was propagated.
*
* unprotect_dirty_bytes_updates: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of times dirty bytes have
* been created via unprotect operations since the last time
* the cleaned list was propagated.
*
* insert_dirty_bytes: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of dirty bytes created
* via insert operations since the last time the cleaned
* list was propagated.
*
* insert_dirty_bytes_updates: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of times dirty bytes have
* been created via insert operations since the last time
* the cleaned list was propagated.
*
* move_dirty_bytes: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of dirty bytes created
* via move operations since the last time the cleaned
* list was propagated.
*
* move_dirty_bytes_updates: This field only exists when the
* H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
*
* It is used to track the number of times dirty bytes have
* been created via move operations since the last time
* the cleaned list was propagated.
*
* Things have changed a bit since the following four fields were defined.
* If metadata_write_strategy is H5AC_METADATA_WRITE_STRATEGY__PROCESS_0_ONLY,
* all comments hold as before -- with the caviate that pending further
* coding, the process 0 metadata cache is forbidden to flush entries outside
* of a sync point.
*
* However, for different metadata write strategies, these fields are used
* only to maintain the correct dirty byte count on process zero -- and in
* most if not all cases, this is redundant, as process zero will be barred
* from flushing entries outside of a sync point.
*
* JRM -- 3/16/10
*
* d_slist_ptr: Pointer to an instance of H5SL_t used to maintain a list
* of entries that have been dirtied since the last time they
* were listed in a clean entries broadcast. This list is
* only maintained by the metadata cache on process 0 -- it
* it used to maintain a view of the dirty entries as seen
* by the other caches, so as to keep the dirty bytes count
* in synchronization with them.
*
* Thus on process 0, the dirty_bytes count is incremented
* only if either
*
* 1) an entry is inserted in the metadata cache, or
*
* 2) a previously clean entry is moved, and it does not
* already appear in the dirty entry list, or
*
* 3) a previously clean entry is unprotected with the
* dirtied flag set and the entry does not already appear
* in the dirty entry list.
*
* Entries are added to the dirty entry list whever they cause
* the dirty bytes count to be increased. They are removed
* when they appear in a clean entries broadcast. Note that
* moves must be reflected in the dirty entry list.
*
* To reitterate, this field is only used on process 0 -- it
* should be NULL on all other processes.
*
* c_slist_ptr: Pointer to an instance of H5SL_t used to maintain a list
* of entries that were dirty, have been flushed
* to disk since the last clean entries broadcast, and are
* still clean. Since only process 0 can write to disk, this
* list only exists on process 0.
*
* In essence, this slist is used to assemble the contents of
* the next clean entries broadcast. The list emptied after
* each broadcast.
*
* The following two fields are used only when metadata_write_strategy
* is H5AC_METADATA_WRITE_STRATEGY__DISTRIBUTED.
*
* candidate_slist_ptr: Pointer to an instance of H5SL_t used by process 0
* to construct a list of entries to be flushed at this sync
* point. This list is then broadcast to the other processes,
* which then either flush or mark clean all entries on it.
*
* write_done: In the parallel test bed, it is necessary to ensure that
* all writes to the server process from cache 0 complete
* before it enters the barrier call with the other caches.
*
* The write_done callback allows t_cache to do this without
* requiring an ACK on each write. Since these ACKs greatly
* increase the run time on some platforms, this is a
* significant optimization.
*
* This field must be set to NULL when the callback is not
* needed.
*
* Note: This field has been extended for use by all processes
* with the addition of support for the distributed
* metadata write strategy.
* JRM -- 5/9/10
*
* sync_point_done: In the parallel test bed, it is necessary to verify
* that the expected writes, and only the expected writes,
* have taken place at the end of each sync point.
*
* The sync_point_done callback allows t_cache to perform
* this verification. The field is set to NULL when the
* callback is not needed.
*
****************************************************************************/
#ifdef H5_HAVE_PARALLEL
#define H5AC__H5AC_AUX_T_MAGIC (unsigned)0x00D0A01
typedef struct H5AC_aux_t
{
uint32_t magic;
MPI_Comm mpi_comm;
int mpi_rank;
int mpi_size;
hbool_t write_permitted;
size_t dirty_bytes_threshold;
size_t dirty_bytes;
int32_t metadata_write_strategy;
#if H5AC_DEBUG_DIRTY_BYTES_CREATION
unsigned dirty_bytes_propagations;
size_t unprotect_dirty_bytes;
unsigned unprotect_dirty_bytes_updates;
size_t insert_dirty_bytes;
unsigned insert_dirty_bytes_updates;
size_t move_dirty_bytes;
unsigned move_dirty_bytes_updates;
#endif /* H5AC_DEBUG_DIRTY_BYTES_CREATION */
H5SL_t * d_slist_ptr;
H5SL_t * c_slist_ptr;
H5SL_t * candidate_slist_ptr;
void (* write_done)(void);
void (* sync_point_done)(int num_writes,
haddr_t * written_entries_tbl);
} H5AC_aux_t; /* struct H5AC_aux_t */
/* Package scoped functions */
H5_DLL herr_t H5AC_set_sync_point_done_callback(H5C_t *cache_ptr,
void (*sync_point_done)(int num_writes, haddr_t *written_entries_tbl));
H5_DLL herr_t H5AC_set_write_done_callback(H5C_t * cache_ptr,
void (* write_done)(void));
#endif /* H5_HAVE_PARALLEL */
/******************************/
/* Pacakge Private Prototypes */
/******************************/
/* Cache logging routines */
H5_DLL herr_t H5AC__write_create_cache_log_msg(H5AC_t *cache);
H5_DLL herr_t H5AC__write_destroy_cache_log_msg(H5AC_t *cache);
H5_DLL herr_t H5AC__write_evict_cache_log_msg(const H5AC_t *cache,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_expunge_entry_log_msg(const H5AC_t *cache,
haddr_t address,
int type_id,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_flush_cache_log_msg(const H5AC_t *cache,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_insert_entry_log_msg(const H5AC_t *cache,
haddr_t address,
int type_id,
unsigned flags,
size_t size,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_mark_dirty_entry_log_msg(const H5AC_t *cache,
const H5AC_info_t *entry,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_move_entry_log_msg(const H5AC_t *cache,
haddr_t old_addr,
haddr_t new_addr,
int type_id,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_pin_entry_log_msg(const H5AC_t *cache,
const H5AC_info_t *entry,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_create_fd_log_msg(const H5AC_t *cache,
const H5AC_info_t *parent,
const H5AC_info_t *child,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_protect_entry_log_msg(const H5AC_t *cache,
const H5AC_info_t *entry,
unsigned flags,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_resize_entry_log_msg(const H5AC_t *cache,
const H5AC_info_t *entry,
size_t new_size,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_unpin_entry_log_msg(const H5AC_t *cache,
const H5AC_info_t *entry,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_destroy_fd_log_msg(const H5AC_t *cache,
const H5AC_info_t *parent,
const H5AC_info_t *child,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_unprotect_entry_log_msg(const H5AC_t *cache,
const H5AC_info_t *entry,
int type_id,
unsigned flags,
herr_t fxn_ret_value);
H5_DLL herr_t H5AC__write_set_cache_config_log_msg(const H5AC_t *cache,
const H5AC_cache_config_t *config,
herr_t fxn_ret_value);
#endif /* _H5ACpkg_H */
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