Merge pull request #45 from vchoi-hdfgroup/feature/vfd_swmr

Feature/vfd swmr

5 files changed, 174 insertions, 105 deletions

diff --git a/test/testvfdswmr.sh.in b/test/testvfdswmr.sh.in
index 4dc1e82..535aafa 100644
--- a/test/testvfdswmr.sh.in
+++ b/test/testvfdswmr.sh.in
@@ -1047,31 +1047,31 @@ fi
 #
 BIGSET_n=25                         # -n option: # of iterations
 BIGSET_few_s=10                     # -s option: # of datasets (for few_big test)
-BIGSET_many_s=100                   # -s option: # of datasets (for many_small test)
+BIGSET_many_s=50                    # -s option: # of datasets (for many_small test)
 #
 #
 # Setting for exhaustive and quick runs
 #
 if [[ "$HDF5TestExpress" -eq 0 ]] ; then         # exhaustive run
-    BIGSET_n=200
-    BIGSET_few_s=100
-    BIGSET_many_s=1000
+    BIGSET_n=100
+    BIGSET_few_s=25
+    BIGSET_many_s=100
 elif [[ "$HDF5TestExpress" -gt 1 ]]; then        # quick run
     BIGSET_n=10
     BIGSET_few_s=3
-    BIGSET_many_s=50
+    BIGSET_many_s=25
 fi
 #
 #
-for options in "-d 1" "-d 1 -F" "-d 2" "-d 2 -F" "-d 1 -t" "-d 1 -t -F" "-d 1 -t -R" "-d 1 -V" "-d 1 -M" "-d 1 -V -F" "-d 1 -M -F"; do
+for options in "-d 1" "-d 1 -F" "-d 2 -l 16" "-d 2 -F -l 16" "-d 1 -t" "-d 1 -t -F" "-d 1 -t -R" "-d 1 -V" "-d 1 -M" "-d 1 -V -F" "-d 1 -M -F"; do
 	if [ ${do_many_small:-no} = no ]; then
 		continue
 	fi
 	#
-	# Test many small datasets of one and two dimensions.
+	# Test many small datasets of two or three dimensions.
 	#
 	# Perform 25 iterations on 100 extensible datasets configured with
-	# 2D 16x16 chunks or 3D 8x16x16 chunks of 32-bit unsigned integer elements,
+	# 2D 16x16 chunks or 3D 1x16x16 chunks of 32-bit unsigned integer elements,
 	# expanding each dataset by a chunk in one dimension (up to 25x1
 	# 16x16 chunks) on each iteration.
 	#
@@ -1079,16 +1079,16 @@ for options in "-d 1" "-d 1 -F" "-d 2" "-d 2 -F" "-d 1 -t" "-d 1 -t -F" "-d 1 -t
 	# in *two* dimensions (up to 25x25 16x16 chunks).
 	#
         # If testing 3D datasets (-t option), extending each dataset along the
-        # first dimension (up to 25 8x16x16)
+        # first dimension (up to 25 1x16x16)
         #
 
 	echo launch vfd_swmr_bigset_writer many small, options $options
 	catch_out_err_and_rc vfd_swmr_bigset_writer \
-	    ../vfd_swmr_bigset_writer -n $BIGSET_n $options -s $BIGSET_many_s -e 8 -r 16 -c 16 -q -l 3 &
+	    ../vfd_swmr_bigset_writer -n $BIGSET_n $options -s $BIGSET_many_s -e 1 -r 16 -c 16 -q &
 	pid_writer=$!
 
 	catch_out_err_and_rc vfd_swmr_bigset_reader \
-	    ../vfd_swmr_bigset_reader -n $BIGSET_n $options -s $BIGSET_many_s -e 8 -r 16 -c 16 -q -l 3 &
+	    ../vfd_swmr_bigset_reader -n $BIGSET_n $options -s $BIGSET_many_s -e 1 -r 16 -c 16 -q &
 	pid_reader=$!
 
 	# Wait for the reader to finish before signalling the
@@ -1116,12 +1116,12 @@ for options in "-d 1" "-d 1 -F" "-d 2" "-d 2 -F" "-d 1 -t" "-d 1 -t -F" "-d 1 -t
 done
 
 # bigset test for bigger chunks
-for options in "-d 1" "-d 1 -F" "-d 2" "-d 2 -F" "-d 1 -t" "-d 1 -t -F" "-d 1 -t -R" "-d 1 -V" "-d 1 -M" "-d 1 -V -F" "-d 1 -M -F"; do
+for options in "-d 1" "-d 1 -F" "-d 2 -l 10" "-d 2 -F -l 10" "-d 1 -t -l 10" "-d 1 -t -F -l 10" "-d 1 -t -R" "-d 1 -V" "-d 1 -M" "-d 1 -V -F" "-d 1 -M -F"; do
 	#
-	# Test a few big datasets of one and two dimensions.
+	# Test a few big datasets of two or three dimensions.
 	#
 	# Perform 25 iterations on 10 extensible datasets configured with
-	# 2D 256x256 chunks or 3D 64x256x256 of 32-bit unsigned integer elements,
+	# 2D 256x256 chunks or 3D 8x256x256 of 32-bit unsigned integer elements,
 	# expanding each dataset by a chunk in one dimension (up to 25x1
 	# 256x256 chunks) on each iteration.
 	#
@@ -1129,7 +1129,7 @@ for options in "-d 1" "-d 1 -F" "-d 2" "-d 2 -F" "-d 1 -t" "-d 1 -t -F" "-d 1 -t
 	# in *two* dimensions (up to 25x25 256x256 chunks).
 	#
         # If testing 3D datasets (-t option), extending each dataset along the
-        # first dimension (up to 25 64x256x256)
+        # first dimension (up to 25 8x256x256)
         #
 
 	if [ ${do_few_big:-no} = no ]; then
@@ -1137,11 +1137,11 @@ for options in "-d 1" "-d 1 -F" "-d 2" "-d 2 -F" "-d 1 -t" "-d 1 -t -F" "-d 1 -t
 	fi
 	echo launch vfd_swmr_bigset_writer few big, options $options ......may take some time......
 	catch_out_err_and_rc vfd_swmr_bigset_writer \
-	    ../vfd_swmr_bigset_writer -n $BIGSET_n $options -s $BIGSET_few_s -e 64 -r 256 -c 256 -q -l 3 &
+	    ../vfd_swmr_bigset_writer -n $BIGSET_n $options -s $BIGSET_few_s -e 8 -r 256 -c 256 -q &
 	pid_writer=$!
 
 	catch_out_err_and_rc vfd_swmr_bigset_reader \
-	    ../vfd_swmr_bigset_reader -n $BIGSET_n $options -s $BIGSET_few_s -e 64 -r 256 -c 256 -q -l 3 &
+	    ../vfd_swmr_bigset_reader -n $BIGSET_n $options -s $BIGSET_few_s -e 8 -r 256 -c 256 -q &
 	pid_reader=$!
 
 	# Wait for the reader to finish before signalling the
diff --git a/test/vfd_swmr_bigset_writer.c b/test/vfd_swmr_bigset_writer.c
index 956973a..77c7b26 100644
--- a/test/vfd_swmr_bigset_writer.c
+++ b/test/vfd_swmr_bigset_writer.c
@@ -149,6 +149,7 @@ typedef struct {
     bool         test_3d;
     enum { vds_off, vds_single, vds_multi } vds;
     bool            use_vfd_swmr;
+    bool            use_legacy_swmr;
     bool            use_named_pipe;
     bool            do_perf;
     bool            cross_chunk_read;
@@ -214,6 +215,7 @@ state_initializer(void)
                      .test_3d          = false,
                      .vds              = vds_off,
                      .use_vfd_swmr     = true,
+                     .use_legacy_swmr  = false,
                      .use_named_pipe   = true,
                      .do_perf          = false,
                      .cross_chunk_read = false,
@@ -256,6 +258,7 @@ usage(const char *progname)
         "-P:                   do the performance measurement\n"
         "-R:                   flush raw data\n"
         "-S:	               do not use VFD SWMR\n"
+        "-T:                   use legacy SWMR (-S and -N must also be specified)\n"
         "-V:	               use virtual datasets and a single\n"
         "                      source file\n"
         "-a steps:	       `steps` between adding attributes\n"
@@ -339,7 +342,7 @@ state_init(state_t *s, int argc, char **argv)
     if (tfile)
         HDfree(tfile);
 
-    while ((ch = getopt(argc, argv, "CFMNPRSVa:bc:d:e:f:g:j:k:l:m:n:o:p:qr:s:tu:v:w:")) != -1) {
+    while ((ch = getopt(argc, argv, "CFMNPRSTVa:bc:d:e:f:g:j:k:l:m:n:o:p:qr:s:tu:v:w:")) != -1) {
         switch (ch) {
             case 'C':
                 /* This flag indicates cross-over chunk read during data validation */
@@ -362,6 +365,9 @@ state_init(state_t *s, int argc, char **argv)
             case 'S':
                 s->use_vfd_swmr = false;
                 break;
+            case 'T':
+                s->use_legacy_swmr = true;
+                break;
             case 'V':
                 s->vds = vds_single;
                 break;
@@ -745,6 +751,18 @@ state_init(state_t *s, int argc, char **argv)
         TEST_ERROR;
     }
 
+    if (s->use_legacy_swmr) {
+        if (s->use_vfd_swmr) {
+            HDfprintf(stderr, "Can't use both VFD SWMR and Legacy SWMR\n");
+            TEST_ERROR;
+        }
+
+        if (s->use_named_pipe) {
+            HDfprintf(stderr, "Can't use named pipe for the Legacy SWMR\n");
+            TEST_ERROR;
+        }
+    }
+
     return true;
 
 error:
@@ -826,14 +844,14 @@ state_destroy(state_t *s)
 
         if (s->vds != vds_multi) {
             if (H5Fvfd_swmr_end_tick(s->file[0]) < 0) {
-                HDfprintf(stderr, "H5Fclose failed\n");
+                HDfprintf(stderr, "H5Fvfd_swmr_end_tick failed\n");
                 TEST_ERROR;
             }
         }
         else {
             for (j = 0; j < NELMTS(s->file); j++)
                 if (H5Fvfd_swmr_end_tick(s->file[j]) < 0) {
-                    HDfprintf(stderr, "H5Fclose failed\n");
+                    HDfprintf(stderr, "H5Fvfd_swmr_end_tick failed\n");
                     TEST_ERROR;
                 }
         }
@@ -2081,7 +2099,7 @@ verify_dsets(state_t s, np_state_t *np, mat_t *mat)
          * the validation of the chunks */
         if (s.use_named_pipe && below_speed_limit(&(last.time), &(s.ival))) {
             AT();
-            HDfprintf(stderr, "verify_extensible_dset took too long to finish\n");
+            HDfprintf(stderr, "Warning: verify_extensible_dset took too long to finish\n");
         }
 
         /* For checking the time lapse between the writer's finishing writing a batch of chunks
@@ -2544,6 +2562,12 @@ main(int argc, char **argv)
             TEST_ERROR;
         }
 
+        /* Enable the Legacy SWMR writing mode if specified */
+        if (s.use_legacy_swmr && H5Fstart_swmr_write(s.file[0]) < 0) {
+            HDfprintf(stderr, "failed to start the Legacy SWMR writing mode\n");
+            TEST_ERROR;
+        }
+
         /* Start to write chunks.  The writer writes as many chunks as possible within a tick, then
          * notify the reader.  But it doesn't receive back the reader's notice. */
         if (!write_dsets(s, &np, mat)) {
diff --git a/test/vfd_swmr_common.c b/test/vfd_swmr_common.c
index f57f39a..cfe93aa 100644
--- a/test/vfd_swmr_common.c
+++ b/test/vfd_swmr_common.c
@@ -369,6 +369,19 @@ init_vfd_swmr_config(H5F_vfd_swmr_config_t *config, uint32_t tick_len, uint32_t
 
 } /* init_vfd_swmr_config() */
 
+/* Initialize the log file path in config, this function should be called after init_vfd_swmr_config.  */
+void
+init_vfd_swmr_log(H5F_vfd_swmr_config_t *config, const char *log_file_fmtstr, ...)
+
+{
+    va_list ap;
+
+    HDva_start(ap, log_file_fmtstr);
+    evsnprintf(config->log_file_path, sizeof(config->log_file_path), log_file_fmtstr, ap);
+    HDva_end(ap);
+
+} /* init_vfd_swmr_log() */
+
 /* Perform common VFD SWMR configuration on the file-access property list:
  * configure page buffering, set reasonable VFD SWMR defaults.
  */
diff --git a/test/vfd_swmr_common.h b/test/vfd_swmr_common.h
index b2fbbbd..f5981a5 100644
--- a/test/vfd_swmr_common.h
+++ b/test/vfd_swmr_common.h
@@ -77,6 +77,9 @@ H5TEST_DLL void init_vfd_swmr_config(H5F_vfd_swmr_config_t *config, uint32_t tic
                                      hbool_t writer, hbool_t flush_raw_data, uint32_t md_pages_reserved,
                                      const char *md_file_fmtstr, ...) H5_ATTR_FORMAT(printf, 7, 8);
 
+H5TEST_DLL void init_vfd_swmr_log(H5F_vfd_swmr_config_t *config, const char *log_file_fmtstr, ...)
+    H5_ATTR_FORMAT(printf, 2, 3);
+
 H5TEST_DLL hid_t vfd_swmr_create_fcpl(H5F_fspace_strategy_t fs_strategy, hsize_t fs_page_size);
 
 H5TEST_DLL void dbgf(int, const char *, ...) H5_ATTR_FORMAT(printf, 2, 3);
diff --git a/test/vfd_swmr_gperf_writer.c b/test/vfd_swmr_gperf_writer.c
index e21f931..3342b40 100644
--- a/test/vfd_swmr_gperf_writer.c
+++ b/test/vfd_swmr_gperf_writer.c
@@ -12,6 +12,12 @@
 
 /* Description of this program:
  * This program checks the performance of group creations for VFD SWMR.
+ * It also has an option to turn on the VFD SWMR logging feature and generates
+ * a log message for group creations. The performance test illustration is in
+ * section I. The log feature illustration is in section II.
+ *
+ * I. Performance tests with options
+ *
  * Currently the group creation time, H5Fopen and H5Fclose time are measured.
  * After compiling the program,
  *     ./vfd_swmr_gperf_writer -n 1000 -P -N 5 -q
@@ -29,6 +35,18 @@
  *      The program is run with max_lag = 8, tick_len = 4;
  *      The page buffer size is 16384 bytes. The page size is 8192 bytes.
  *
+ * II. How to generate log message
+ *
+ *     ./vfd_swmr_gperf_writer -n 100000 -P -L -q
+ * will generate 100000 groups, each group has one attribute.  It also writes the log message
+ *      to file "log-test" under the same directory.
+ *      To turn on the log feature, one just needs to provide the log file path as
+ *      indicated by the line init_vfd_swmr_log(&config, "./log-test") in the main
+ *      function. The init_vfd_swmr_log is defined inside the vfd_swmr_common.c.
+ *      The "log-test" should include something like:
+ *      'EOT_PROCESSING_TIME       : 0.040 s: Writer time is 1 milliseconds'
+ *      The standard output of performance measurement can help check the correctness in the "log-test".
+ *
  */
 #define H5F_FRIEND /*suppress error about including H5Fpkg   */
 
@@ -63,6 +81,7 @@ typedef struct {
     uint32_t     max_lag;
     uint32_t     tick_len;
     bool         gperf;
+    bool         glog;
     double       min_gc_time;
     double       max_gc_time;
     double       mean_gc_time;
@@ -84,7 +103,7 @@ typedef struct {
         .file = H5I_INVALID_HID, .one_by_one_sid = H5I_INVALID_HID, .filename = "",                          \
         .filetype = H5T_NATIVE_UINT32, .asteps = 1, .nsteps = 100, .use_vfd_swmr = true,                     \
         .old_style_grp = false, .grp_op_pattern = ' ', .grp_op_test = false, .at_pattern = ' ',              \
-        .attr_test = false, .tick_len = 4, .max_lag = 7, .gperf = false, .min_gc_time = 100.,                \
+        .attr_test = false, .tick_len = 4, .max_lag = 7, .gperf = false, .glog = false, .min_gc_time = 100., \
         .max_gc_time = 0., .mean_gc_time = 0., .total_gc_time = 0., .total_time = 0., .mean_time = 0.,       \
         .fo_total_time = 0., .fc_total_time = 0., .num_attrs = 1, .vlstr_test = false, .ps = 4096,           \
         .pbs = 4096, .nglevels = 0                                                                           \
@@ -93,88 +112,91 @@ typedef struct {
 static void
 usage(const char *progname)
 {
-    fprintf(stderr,
-            "usage: ./%s -P -n 1000 -N 5 -q (create 1000 groups, each group has 5 attributes)\n"
-            "Options: \n"
-            " [-P] [-S] [-G] [-t tick_len] [-m max_lag][-B pbs] [-s ps]\n"
-            " [-n ngroups] [-l ng_levels] [-O grp_op_pattern]\n"
-            " [-N num_attrs] [-V] [-b] [-A at_pattern] [-a steps] [-q]\n"
-            "\n"
-            "-P:             carry out the performance test\n"
-            "-S:             do not use VFD SWMR\n"
-            "-G:             old-style type of group\n"
-            "-t tick_len:    length of a tick in tenths of a second.\n"
-            "-m max_lag:     maximum expected lag(in ticks) between writer and readers\n"
-            "-B pbs:         page Buffer Size in bytes:\n"
-            "                The default value is 4K(4096).\n"
-            "-s ps:          page size used by page aggregation, page buffer and \n"
-            "                the metadata file. \n"
-            "-n ngroups:     the number of groups\n"
-            "-l ng_levels:   the number of level of nested groups.  \n"
-            "                If all the groups are under the root group,  \n"
-            "                this number should be 0.\n"
-            "-N num_attrs:   the number of attributes \n"
-            "-V              use variable length string attributes for performance test\n"
-            "-b:             write data in big-endian byte order\n"
-            "                (For the performance test, -V overwrites -b)\n"
-            "-A at_pattern:  `at_pattern' for different attribute tests\n"
-            "              The value of `at_pattern` is one of the following:\n"
-            "              `compact`              - Attributes added in compact storage\n"
-            "              `dense`                - An attribute added in dense storage\n"
-            "              `compact-del`          - Attributes added and then one\n"
-            "                                       attribute deleted, in compact \n"
-            "              `dense-del`            - Attributes added until the storage\n"
-            "                                       is dense then an attribute deleted\n"
-            "                                       the storge still in dense\n"
-            "              `compact-add-to-dense` - Attributes added first in compact\n"
-            "                                       then in dense storage\n"
-            "              `dense-del-to-compact` - Attributes added until the storage\n"
-            "                                       is dense, then several attributes \n"
-            "                                       deleted, the storage changed to\n"
-            "                                       compact\n"
-            "              `modify`               - An attribute added then modified\n"
-            "              `add-vstr`             - A VL string attribute added\n"
-            "              `remove-vstr`          - A VL string attribute added then\n"
-            "                                       deleted\n"
-            "              `modify-vstr`          - A VL string attribute added then \n"
-            "                                       modified \n"
-            "              `add-ohr-block`        - An attribute is added and this forces\n"
-            "                                       the creation of object header\n"
-            "                                       continuation block \n"
-            "              `del-ohr-block`        - An attribute is added and this forces\n"
-            "                                       the creation of object header\n"
-            "                                       continuation block and then this \n"
-            "                                       attribute is deleted so the \n"
-            "                                       object header continuation block is \n"
-            "                                       removed. \n"
-            "-O grp_op_pattern:  `grp_op_pattern' for different group operation tests\n"
-            "              The value of `grp_op_pattern` is one of the following:\n"
-            "              `grp-creation`         - A group is created.\n"
-            "              `grp-deletion`         - An existing group is deleted.\n"
-            "              `grp-move`             - A group is moved to become \n"
-            "                                       another group. \n"
-            "              `grp-ins-links`        - Links are inserted, including\n"
-            "                                       both hard and soft links. \n"
-            "              `grp-del-links`        - Links are deleted, including\n"
-            "                                       both hard ans soft links. \n"
-            "              `grp-compact-t-dense`  - Links are inserted to the group.\n"
-            "                                       The link storage of this group \n"
-            "                                       changed from compact to dense. \n"
-            "                                       The links include both hard and\n"
-            "                                       soft links.                    \n"
-            "              `grp-dense-t-compact`  - Links are inserted to the group\n"
-            "                                       The link storage of this group \n"
-            "                                       changed from compact to dense. \n"
-            "                                       Then several links are deleted.\n"
-            "                                       The link storage changed from  \n"
-            "                                       dense to compact again.        \n"
-            "                                       The links include both hard and\n"
-            "                                       soft links.                    \n"
-            "-a steps:      `steps` between adding attributes\n"
-            "              (Don't recommend to use this option for performance test.)\n"
-            "-q:             silence printouts, few messages\n"
-            "\n",
-            progname);
+    fprintf(
+        stderr,
+        "usage: ./%s -P -n 1000 -N 5 -q (create 1000 groups, each group has 5 attributes)\n"
+        "usage: ./%s -P -L -n 100000 -q (create 100000 groups and generate log message to file 'log-test')\n"
+        "Options: \n"
+        " [-P] [-S] [-G] [-L] [-t tick_len] [-m max_lag][-B pbs] [-s ps]\n"
+        " [-n ngroups] [-l ng_levels] [-O grp_op_pattern]\n"
+        " [-N num_attrs] [-V] [-b] [-A at_pattern] [-a steps] [-q]\n"
+        "\n"
+        "-P:             carry out the performance test\n"
+        "-S:             do not use VFD SWMR\n"
+        "-G:             old-style type of group\n"
+        "-L:             Turn on the logging feature.\n"
+        "-t tick_len:    length of a tick in tenths of a second.\n"
+        "-m max_lag:     maximum expected lag(in ticks) between writer and readers\n"
+        "-B pbs:         page Buffer Size in bytes:\n"
+        "                The default value is 4K(4096).\n"
+        "-s ps:          page size used by page aggregation, page buffer and \n"
+        "                the metadata file. \n"
+        "-n ngroups:     the number of groups\n"
+        "-l ng_levels:   the number of level of nested groups.  \n"
+        "                If all the groups are under the root group,  \n"
+        "                this number should be 0.\n"
+        "-N num_attrs:   the number of attributes \n"
+        "-V              use variable length string attributes for performance test\n"
+        "-b:             write data in big-endian byte order\n"
+        "                (For the performance test, -V overwrites -b)\n"
+        "-A at_pattern:  `at_pattern' for different attribute tests\n"
+        "              The value of `at_pattern` is one of the following:\n"
+        "              `compact`              - Attributes added in compact storage\n"
+        "              `dense`                - An attribute added in dense storage\n"
+        "              `compact-del`          - Attributes added and then one\n"
+        "                                       attribute deleted, in compact \n"
+        "              `dense-del`            - Attributes added until the storage\n"
+        "                                       is dense then an attribute deleted\n"
+        "                                       the storge still in dense\n"
+        "              `compact-add-to-dense` - Attributes added first in compact\n"
+        "                                       then in dense storage\n"
+        "              `dense-del-to-compact` - Attributes added until the storage\n"
+        "                                       is dense, then several attributes \n"
+        "                                       deleted, the storage changed to\n"
+        "                                       compact\n"
+        "              `modify`               - An attribute added then modified\n"
+        "              `add-vstr`             - A VL string attribute added\n"
+        "              `remove-vstr`          - A VL string attribute added then\n"
+        "                                       deleted\n"
+        "              `modify-vstr`          - A VL string attribute added then \n"
+        "                                       modified \n"
+        "              `add-ohr-block`        - An attribute is added and this forces\n"
+        "                                       the creation of object header\n"
+        "                                       continuation block \n"
+        "              `del-ohr-block`        - An attribute is added and this forces\n"
+        "                                       the creation of object header\n"
+        "                                       continuation block and then this \n"
+        "                                       attribute is deleted so the \n"
+        "                                       object header continuation block is \n"
+        "                                       removed. \n"
+        "-O grp_op_pattern:  `grp_op_pattern' for different group operation tests\n"
+        "              The value of `grp_op_pattern` is one of the following:\n"
+        "              `grp-creation`         - A group is created.\n"
+        "              `grp-deletion`         - An existing group is deleted.\n"
+        "              `grp-move`             - A group is moved to become \n"
+        "                                       another group. \n"
+        "              `grp-ins-links`        - Links are inserted, including\n"
+        "                                       both hard and soft links. \n"
+        "              `grp-del-links`        - Links are deleted, including\n"
+        "                                       both hard ans soft links. \n"
+        "              `grp-compact-t-dense`  - Links are inserted to the group.\n"
+        "                                       The link storage of this group \n"
+        "                                       changed from compact to dense. \n"
+        "                                       The links include both hard and\n"
+        "                                       soft links.                    \n"
+        "              `grp-dense-t-compact`  - Links are inserted to the group\n"
+        "                                       The link storage of this group \n"
+        "                                       changed from compact to dense. \n"
+        "                                       Then several links are deleted.\n"
+        "                                       The link storage changed from  \n"
+        "                                       dense to compact again.        \n"
+        "                                       The links include both hard and\n"
+        "                                       soft links.                    \n"
+        "-a steps:      `steps` between adding attributes\n"
+        "              (Don't recommend to use this option for performance test.)\n"
+        "-q:             silence printouts, few messages\n"
+        "\n",
+        progname, progname);
     exit(EXIT_FAILURE);
 }
 
@@ -203,7 +225,7 @@ state_init(state_t *s, int argc, char **argv)
 
     if (argc == 1)
         usage(s->progname);
-    while ((ch = getopt(argc, argv, "PSGa:bVt:m:B:s:n:qA:N:l:O:")) != -1) {
+    while ((ch = getopt(argc, argv, "PSGLa:bVt:m:B:s:n:qA:N:l:O:")) != -1) {
         switch (ch) {
             case 'P':
                 s->gperf = true;
@@ -214,6 +236,9 @@ state_init(state_t *s, int argc, char **argv)
             case 'G':
                 s->old_style_grp = true;
                 break;
+            case 'L':
+                s->glog = true;
+                break;
             case 'a':
             case 'n':
             case 'N':
@@ -2764,6 +2789,10 @@ main(int argc, char **argv)
     /* config, tick_len, max_lag, writer, flush_raw_data, md_pages_reserved, md_file_path */
     init_vfd_swmr_config(&config, s.tick_len, s.max_lag, writer, FALSE, 128, "./group-shadow");
 
+    /* If the log flag is on, create the log file log-test under the current directory. */
+    if (s.glog == true)
+        init_vfd_swmr_log(&config, "./log-test");
+
     /* If old-style option is chosen, use the earliest file format(H5F_LIBVER_EARLIEST)
      * as the second parameter of H5Pset_libver_bound() that is called by
      * vfd_swmr_create_fapl. Otherwise, the latest file format(H5F_LIBVER_LATEST)