first stab at an asynchronous memory-mapped dumping mechanism. the dump...

first stab at an asynchronous memory-mapped dumping mechanism. the dump compiles, but cannot test yet as the test relies on a threadpool.

src/Makefile.am

@@ -36,14 +36,15 @@ endif
 include_HEADERS = space.h runner.h queue.h task.h lock.h cell.h part.h const.h \
     engine.h swift.h serial_io.h timers.h debug.h scheduler.h proxy.h parallel_io.h \
     common_io.h single_io.h multipole.h map.h tools.h partition.h clocks.h parser.h \
-    physical_constants.h physical_constants_cgs.h potentials.h version.h hydro_properties.h
+    physical_constants.h physical_constants_cgs.h potentials.h version.h hydro_properties.h \
+    dump.h
 
 # Common source files
 AM_SOURCES = space.c runner.c queue.c task.c cell.c engine.c \
     serial_io.c timers.c debug.c scheduler.c proxy.c parallel_io.c \
     units.c common_io.c single_io.c multipole.c version.c map.c \
     kernel_hydro.c kernel_gravity.c tools.c part.c partition.c clocks.c parser.c \
-    physical_constants.c potentials.c hydro_properties.c
+    physical_constants.c potentials.c hydro_properties.c dump.c
 
 # Include files for distribution, not installation.
 nobase_noinst_HEADERS = approx_math.h atomic.h cycle.h error.h inline.h kernel_hydro.h kernel_gravity.h \

src/dump.c

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2016 Pedro Gonnet (pedro.gonnet@durham.ac.uk)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+
+/* Config parameters. */
+#include "../config.h"
+
+/* Some standard headers. */
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/* This object's header. */
+#include "dump.h"
+
+/* Local headers. */
+#include "atomic.h"
+#include "error.h"
+
+/**
+ * @brief Obtain a chunk of memory from a dump.
+ *
+ * @param d The #dump.
+ * @param count The number of bytes requested.
+ * @param offset The offset of the returned memory address within the dump file.
+ * @return A pointer to the memory-mapped chunk of data.
+ */
+
+void *dump_get(struct dump *d, size_t count, size_t *offset) {
+  size_t local_offset = atomic_add(&d->count, count);
+  *offset = local_offset + d->file_offset;
+  return d->data + local_offset;
+}
+
+/**
+ * @brief Ensure that at least size bytes are available in the #dump.
+ */
+
+void dump_ensure(struct dump *d, size_t size) {
+
+  /* If we have enough space already, just bail. */
+  if (d->size - d->count > size) return;
+
+  /* Unmap the current data. */
+  if (munmap(d->data, d->count) != 0) error("Failed to unmap dump data.");
+
+  /* Re-map starting at the end of the file. */
+  d->file_offset += d->count;
+  d->size = size * dump_grow_ensure_factor;
+  if ((d->data = mmap(NULL, d->size, PROT_WRITE, MAP_PRIVATE, d->fd,
+                      d->file_offset)) == MAP_FAILED) {
+    error("Failed to allocate map of size %zi bytes.", size);
+  }
+
+  /* Re-set the counter. */
+  d->count = 0;
+}
+
+/**
+ * @brief Flush the #dump to disk.
+ */
+
+void dump_sync(struct dump *d) {
+  if (msync(d->data, d->count, MS_SYNC) != 0)
+    error("Failed to sync memory-mapped data.");
+}
+
+/**
+ * @brief Finalize the #dump.
+ */
+
+void dump_close(struct dump *d) {
+  /* Unmap the data in memory. */
+  if (munmap(d->data, d->count) != 0) error("Failed to unmap dump data.");
+
+  /* Close the memory-mapped file. */
+  if (close(d->fd) != 0) error("Failed to close memory-mapped file.");
+}
+
+/**
+ * @brief Initialize a file dump.
+ *
+ * @param d The #dump to initialize.
+ * @param filename The fully qualified name of the file in which to dump,
+ *                 note that it will be overwritten.
+ * @param size The initial buffer size for this #dump.
+ */
+
+void dump_init(struct dump *d, const char *filename, size_t size) {
+
+  /* Create the output file. */
+  if ((d->fd = open(filename, O_WRONLY)) == -1) {
+    error("Failed to create dump file '%s' (%s).", filename, strerror(errno));
+  }
+
+  /* Map memory to the created file. */
+  if ((d->data = mmap(NULL, size, PROT_WRITE, MAP_PRIVATE, d->fd, 0)) ==
+      MAP_FAILED) {
+    error("Failed to allocate map of size %zi bytes.", size);
+  }
+
+  /* Init some counters. */
+  d->size = size;
+  d->count = 0;
+  d->file_offset = 0;
+}

src/dump.h

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2016 Pedro Gonnet (pedro.gonnet@durham.ac.uk)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#ifndef SWIFT_DUMP_H
+#define SWIFT_DUMP_H
+
+/* Includes. */
+#include "cell.h"
+#include "lock.h"
+#include "task.h"
+
+/* Some constants. */
+#define dump_grow_ensure_factor 10
+
+/** The dump struct. */
+struct dump {
+
+  /* The memory-mapped data of this dump. */
+  void *data;
+  
+  /* The size of the memory-mapped data, in bytes. */
+  size_t size;
+  
+  /* The number of bytes that have been dumped. */
+  size_t count;
+  
+  /* The offset of the data within the current file. */
+  size_t file_offset;
+  
+  /* The file with which this memory is associated. */
+  int fd;
+  
+};
+
+/* Function prototypes. */
+void dump_init(struct dump *d, const char *filename, size_t size);
+void dump_ensure(struct dump *d, size_t size);
+void dump_sync(struct dump *d);
+void dump_close(struct dump *d);
+void *dump_get(struct dump *d, size_t count, size_t *offset);
+
+#endif /* SWIFT_DUMP_H */

tests/Makefile.am

@@ -22,11 +22,11 @@ AM_LDFLAGS = ../src/.libs/libswiftsim.a $(HDF5_LDFLAGS) $(HDF5_LIBS)
 
 # List of programs and scripts to run in the test suite
 TESTS = testGreetings testReading.sh testSingle testPair.sh testPairPerturbed.sh \
-	test27cells.sh test27cellsPerturbed.sh testParser.sh testKernel
+	test27cells.sh test27cellsPerturbed.sh testParser.sh testKernel dump_test
 
 # List of test programs to compile
 check_PROGRAMS = testGreetings testReading testSingle testTimeIntegration \
-		 testSPHStep testPair test27cells testParser testKernel
+		 testSPHStep testPair test27cells testParser testKernel dump_test
 
 # Sources for the individual programs
 testGreetings_SOURCES = testGreetings.c
@@ -47,6 +47,8 @@ testParser_SOURCES = testParser.c
 
 testKernel_SOURCES = testKernel.c
 
+dump_test_SOURCES = dump_test.c
+
 # Files necessary for distribution
 EXTRA_DIST = testReading.sh makeInput.py testPair.sh testPairPerturbed.sh \
 	     test27cells.sh test27cellsPerturbed.sh tolerance.dat testParser.sh \

tests/dump_test.c

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2016 Pedro Gonnet (pedro.gonnet@durham.ac.uk)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+
+/* Config parameters. */
+#include "../config.h"
+
+/* Some standard headers. */
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/* This object's header. */
+#include "dump.h"
+
+/* Local headers. */
+#include "threadpool.h"
+
+void dump_mapper(void *map_data, int num_elements, void *extra_data) {
+  struct dump *d = (struct dump *)extra_data;
+  int offset;
+  char *out_string = dump_get(d, 7, &offset);
+  snprintf(7, "%06i\n", offset);
+}
+
+int main(int argc, char *argv[]) {
+
+  /* Some constants. */
+  const int num_threads = 4;
+  const char *filename = "/tmp/dump_test.out";
+  const int num_runs = 20;
+  const int chunk_size = 1000;
+
+  /* Prepare a threadpool to write to the dump. */
+  struct threadpool t;
+  threadpool_init(&t, num_threads);
+
+  /* Prepare a dump. */
+  struct dump d;
+  dump_init(&d, filename, 1024);
+
+  /* Dump numbers in chunks. */
+  for (int run = 0; runs < num_runs; runs++) {
+
+    /* Ensure capacity. */
+    dump_ensure(&d, 7 * chunk_size);
+
+    /* Dump a few numbers. */
+    threadpool_map(&t, dump_mapper, NULL, chunk_size, 0, 1, &d);
+  }
+
+  /* Finalize the dump. */
+  dump_close(&d);
+}