* be misrepresented as being the original software.
* o This notice may not be removed or altered from any source
* distribution.
- * Authors: Walter Bright, Sean Kelly
+ * Authors: Walter Bright, Sean Kelly, Leandro Lucarella
*/
module rt.gc.cdgc.stats;
+import gc = rt.gc.cdgc.gc;
+import rt.gc.cdgc.bits: GCBits;
+import rt.gc.cdgc.opts: options;
+
+import cstdio = tango.stdc.stdio;
+import ctime = tango.stdc.posix.sys.time;
+
+
+private:
+
+
+/**
+ * Time information for a collection.
+ *
+ * This struct groups all the timing information for a particular collection.
+ * It stores how much time it took the different parts of a collection, splat
+ * in: allocation time (the time the mutator spent in the malloc() call that
+ * triggered the collection), time the world was stopped because of the
+ * collection and the time spent in the collection itself. The time the world
+ * was stopped includes the time spent in the collection (in this
+ * implementation, which is not concurrent) and the time spent in the
+ * allocation includes the time the world was stopped (this is probably true
+ * for any implementation).
+ */
+struct TimeInfo
+{
+ /// Collection time (in seconds).
+ double collection = -1.0;
+ /// Stop-the-world time (in seconds).
+ double stop_the_world = -1.0;
+ /// Time spent in the malloc that triggered the collection (in seconds).
+ double malloc = -1.0;
+}
+
+
+/**
+ * Memory (space) information for a collection.
+ *
+ * This struct groups all the space information for a particular collection.
+ * The space is partitioned in four: used, free, wasted and overhead. "used" is
+ * the net space needed by the mutator; "free" is the space the GC has ready to
+ * be given to the mutator when needed; "wasted" is memory that can't be used
+ * by neither the collector nor the mutator (usually because of fragmentation)
+ * and "overhead" is the space needed by the GC itself.
+ */
+struct MemoryInfo
+{
+ /// Heap memory used by the program (in bytes).
+ size_t used = 0;
+ /// Free heap memory (in bytes).
+ size_t free = 0;
+ /// Memory that can't be used at all (in bytes).
+ size_t wasted = 0;
+ /// Memory used by the GC for bookkeeping (in bytes).
+ size_t overhead = 0;
+}
+
+
+/**
+ * Information about a particular collection.
+ *
+ * This struct groups all information related to a particular collection. The
+ * timings for the collection as stored and the space requirements are both,
+ * before and after that collection, logged to easily measure how effective
+ * the collection was in terms of space. The time when this collection was
+ * triggered is logged too (relative to the program start, in seconds).
+ *
+ * See_Also: TimeInfo and MemoryInfo structs.
+ */
+struct CollectionInfo
+{
+ /// When this information were taken (seconds since the program started).
+ double timestamp = -1.0;
+ /// Time statistics for this collection.
+ TimeInfo time;
+ /// Memory statistics before the collection.
+ MemoryInfo before;
+ /// Memory statistics after the collection.
+ MemoryInfo after;
+}
+
+
+/**
+ * Information about a particular allocation.
+ *
+ * This struct groups all the information about a particular allocation. The
+ * size requested in that allocation is logged, as well as the attributes
+ * assigned to that cell, the time malloc() took to complete and if
+ * a collection was triggered. The time when this allocation was requested is
+ * logged too (relative to the program start, in seconds).
+ */
+struct MallocInfo
+{
+ /// When this information were taken (seconds since the program started).
+ double timestamp = -1.0;
+ /// Time spent in the malloc() call (in seconds).
+ double time = -1.0;
+ /// Memory requested by the malloc() call (in bytes).
+ size_t size = 0;
+ /// Memory attributes as BlkAttr flags.
+ uint attr = 0;
+ /// True if this malloc() triggered a collection.
+ bool collected = false;
+}
+
+
+package:
+
+/**
+ * Control and store the GC statistics.
+ *
+ * This is the interface to this module, it has methods for the GC to inform
+ * when a relevant event has happened. The events are the start and finish of
+ * an allocation, when the world is stopped and restarted and when
+ * a collection is triggered and done.
+ *
+ * All the data is logged in memory and printed to the standard output when
+ * requested (usually at the end of the program).
+ *
+ * See_Also: CollectionInfo and MallocInfo structs.
+ */
+struct Stats
+{
+
+private:
+
+ /// The GC instance we are collecting stats from.
+ .gc.GC gc = null;
+
+ /// True if statistics should be collected.
+ bool active = false;
+
+ /// Current collection information (printed when the malloc finishes).
+ MallocInfo malloc_info;
+
+ /// File where to write the malloc information to.
+ cstdio.FILE* mallocs_file;
+
+ /// Current collection information (printed when the collection finishes).
+ CollectionInfo collection_info;
+
+ /// File where to write the collections information to.
+ cstdio.FILE* collections_file;
+
+ /// Time when the program started.
+ double program_start = -1.0;
+
+ /// Return the current time as seconds since the epoch.
+ static double now()
+ {
+ ctime.timeval tv;
+ ctime.gettimeofday(&tv, null);
+ return cast(double) tv.tv_sec + cast(double) tv.tv_usec / 1_000_000.0;
+ }
+
+ /// Fill a MemoryInfo struct with the current state of the GC heap.
+ void fill_memory_info(MemoryInfo* mem_info)
+ {
+ mem_info.overhead += .gc.GC.classinfo.init.length + .gc.Gcx.sizeof
+ + .gc.pools.size_of + .gc.roots.size_of + .gc.ranges.size_of;
+
+ // pools
+ for (size_t i = 0; i < .gc.pools.length; i++)
+ {
+ auto pool = .gc.pools[i];
+ mem_info.overhead += pool.npages * ubyte.sizeof;
+ // the 5 bitmaps (mark, scan, free, final, noscan)
+ mem_info.overhead += 5 * (GCBits.sizeof
+ + (pool.mark.nwords + 2) * uint.sizeof);
+
+ for (size_t pn = 0; pn < pool.npages; pn++)
+ {
+ auto bin = cast(.gc.Bins) pool.pagetable[pn];
+ if (bin < .gc.B_PAGE)
+ {
+ size_t size = .gc.binsize[bin];
+ size_t bitstride = size / 16;
+ size_t bitbase = pn * (.gc.PAGESIZE / 16);
+ size_t bittop = bitbase + (.gc.PAGESIZE / 16);
+ for (auto biti = bitbase; biti < bittop; biti += bitstride)
+ {
+ if (pool.freebits.test(biti))
+ mem_info.free += size;
+ else
+ mem_info.used += size; // TODO: wasted
+ }
+ }
+ else if (bin == .gc.B_FREE)
+ mem_info.free += .gc.PAGESIZE;
+ else // B_PAGE / B_PAGEPLUS
+ mem_info.used += .gc.PAGESIZE; // TODO: wasted
+ }
+ }
+ }
+
+ cstdio.FILE* start_file(char* filename, char* header)
+ {
+ cstdio.FILE* file = cstdio.fopen(filename, "w");
+ assert (file !is null);
+ cstdio.fputs(header, file);
+ return file;
+ }
+
+ void print_malloc()
+ {
+ if (this.mallocs_file is null)
+ return;
+ cstdio.fprintf(this.mallocs_file,
+ "%f,%f,%zu,%zu,%zu,%zu,%zu\n",
+ //0 1 2 3 4 5 6
+ this.malloc_info.timestamp, // 0
+ this.malloc_info.time, // 1
+ this.malloc_info.size, // 2
+ this.malloc_info.collected ? 1u : 0u, // 3
+ this.malloc_info.attr & .gc.BlkAttr.FINALIZE, // 4
+ this.malloc_info.attr & .gc.BlkAttr.NO_SCAN, // 5
+ this.malloc_info.attr & .gc.BlkAttr.NO_MOVE); // 6
+ }
+
+ void print_collection()
+ {
+ if (this.collections_file is null)
+ return;
+ cstdio.fprintf(this.collections_file,
+ "%f,%f,%f,%f,%zu,%zu,%zu,%zu,%zu,%zu,%zu,%zu\n",
+ //0 1 2 3 4 5 6 7 8 9 10 11
+ this.collection_info.timestamp, // 0
+ this.collection_info.time.malloc, // 1
+ this.collection_info.time.collection, // 2
+ this.collection_info.time.stop_the_world, // 3
+ this.collection_info.before.used, // 4
+ this.collection_info.before.free, // 5
+ this.collection_info.before.wasted, // 6
+ this.collection_info.before.overhead, // 7
+ this.collection_info.after.used, // 8
+ this.collection_info.after.free, // 9
+ this.collection_info.after.wasted, // 10
+ this.collection_info.after.overhead); // 11
+ }
+
+
+public:
+
+ /**
+ * Construct a Stats object (useful for easy initialization).
+ *
+ * This function should be always used to initialize a Stats object because
+ * the program start time (in seconds since the epoch) needs to be taken to
+ * properly add timestamps to allocations and collections.
+ */
+ static Stats opCall(.gc.GC gc)
+ {
+ Stats this_;
+ this_.gc = gc;
+ if (options.malloc_stats_file[0] != '\0') {
+ this_.active = true;
+ this_.mallocs_file = this_.start_file(
+ options.malloc_stats_file.ptr,
+ "Timestamp,Time,Size,Collection triggered,"
+ "Finalize,No scan,No move\n");
+ }
+ // collection
+ if (options.collect_stats_file[0] != '\0') {
+ this_.active = true;
+ this_.collections_file = this_.start_file(
+ options.collect_stats_file.ptr,
+ "Timestamp,Malloc time,Collection time,Stop-the-world time,"
+ "Used before,Free before,Wasted before,Overhead before,"
+ "Used after,Free after,Wasted after,Overhead after\n");
+ }
+ this_.program_start = this_.now();
+ return this_;
+ }
+
+ void finalize()
+ {
+ if (this.mallocs_file !is null)
+ cstdio.fclose(this.mallocs_file);
+ if (this.collections_file !is null)
+ cstdio.fclose(this.collections_file);
+ }
+
+ /// Inform the start of an allocation.
+ void malloc_started(size_t size, uint attr)
+ {
+ if (!this.active)
+ return;
+ auto now = this.now();
+ auto relative_now = now - this.program_start;
+ // malloc
+ this.malloc_info = this.malloc_info.init;
+ this.malloc_info.timestamp = relative_now;
+ this.malloc_info.time = now;
+ this.malloc_info.size = size;
+ this.malloc_info.attr = attr;
+ // this.malloc_info.collected is filled in malloc_finished()
+ // collection
+ this.collection_info = this.collection_info.init;
+ this.collection_info.timestamp = relative_now;
+ // this.collection_info.time.malloc is the same as malloc_info.time
+ }
+
+ /// Inform the end of an allocation.
+ void malloc_finished()
+ {
+ if (!this.active)
+ return;
+ auto now = this.now();
+ auto collected = !(this.collection_info.time.collection < 0.0);
+ // malloc
+ this.malloc_info.time = now - this.malloc_info.time;
+ if (collected)
+ this.malloc_info.collected = true;
+ this.print_malloc();
+ if (!collected)
+ return;
+ // collection
+ this.collection_info.time.malloc = this.malloc_info.time;
+ this.print_collection();
+ }
+
+ /// Inform that all threads (the world) have been stopped.
+ void world_stopped()
+ {
+ if (!this.active)
+ return;
+ this.collection_info.time.stop_the_world = this.now();
+ }
+
+ /// Inform that all threads (the world) have been resumed.
+ void world_started()
+ {
+ if (!this.active)
+ return;
+ this.collection_info.time.stop_the_world =
+ this.now() - this.collection_info.time.stop_the_world;
+ }
+
+ /// Inform the start of a collection.
+ void collection_started()
+ {
+ if (!this.active)
+ return;
+ this.fill_memory_info(&this.collection_info.before);
+ this.collection_info.time.collection = this.now();
+ }
+
+ /// Inform the end of a collection.
+ void collection_finished()
+ {
+ if (!this.active)
+ return;
+ this.collection_info.time.collection =
+ this.now() - this.collection_info.time.collection;
+ this.fill_memory_info(&this.collection_info.after);
+ }
+
+}
+
+
/**
*
*/
projects / software / dgc / cdgc.git / commitdiff