mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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7bb4b2cefe
Original commit message from CVS: Added a fast non-blocking memchunk implementation, it's about 20x faster than a mutex based implementation.
96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
#include "gstmemchunk.h"
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#ifdef __SMP__
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#define CHUNK_LOCK "lock ; "
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#else
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#define CHUNK_LOCK ""
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#endif
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static void
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setup_area (guint8 *area, gint chunk_size, gulong area_size)
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{
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gint i;
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g_print ("setup area at %p, real area_size %lu, chunk size %d\n", area, area_size, chunk_size);
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for (i = 0; i < area_size; i += chunk_size) {
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guint8 *next;
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next = area + chunk_size;
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((GstMemChunkElement *)area)->link = (gpointer)(next);
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area = next;
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}
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}
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GstMemChunk *
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gst_mem_chunk_new (gchar * name, gint atom_size, gulong area_size, gint type)
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{
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GstMemChunk *mem_chunk;
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gint chunk_size;
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g_print ("create: atom size %d, area_size %lu\n", atom_size, area_size);
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chunk_size = atom_size + sizeof (gpointer);
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area_size = (area_size/atom_size) * chunk_size;
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g_print ("chunk size %d, real area_size %lu\n", chunk_size, area_size);
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mem_chunk = g_malloc (sizeof (GstMemChunk));
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mem_chunk->free = g_malloc0 (area_size);
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mem_chunk->cnt = 0;
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mem_chunk->atom_size = atom_size;
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mem_chunk->chunk_size = chunk_size;
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mem_chunk->area_size = area_size;
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setup_area ((guint8 *)mem_chunk->free, chunk_size, area_size);
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return mem_chunk;
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}
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gpointer
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gst_mem_chunk_alloc (GstMemChunk *mem_chunk)
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{
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guint8 *chunk = NULL;
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g_return_val_if_fail (mem_chunk != NULL, NULL);
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__asm__ __volatile__ ("testl %%eax, %%eax \n\t"
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"jz 20f \n"
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"10:\t"
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"movl (%%eax), %%ebx \n\t"
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"movl %%edx, %%ecx \n\t"
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"incl %%ecx \n\t"
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CHUNK_LOCK "cmpxchg8b %1 \n\t"
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"jz 20f \n\t"
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"testl %%eax, %%eax \n\t"
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"jnz 10b \n"
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"20:\t":"=a" (chunk):"m" (*mem_chunk),
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"a" (mem_chunk->free), "d" (mem_chunk->cnt):"ecx",
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"ebx");
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if (chunk)
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chunk += sizeof (gpointer);
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else {
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g_print ("empty\n");
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exit (-1);
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}
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return (gpointer) chunk;
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}
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void
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gst_mem_chunk_free (GstMemChunk *mem_chunk, gpointer mem)
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{
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guint8 *chunk = ((guint8 *)mem) - sizeof (gpointer);
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g_return_if_fail (mem_chunk != NULL);
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g_return_if_fail (mem != NULL);
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__asm__ __volatile__ ( "1:\t"
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"movl %2, (%1) \n"
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CHUNK_LOCK "cmpxchg %1, %0 \n\t"
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"jnz 1b \n\t"::"m" (*mem_chunk), "r" (chunk), "a" (mem_chunk->free));
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}
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