Commit c1bc6626 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Amit Shah
Browse files

multithread decompression: Avoid one copy 



qemu_get_buffer does a copy, we can avoid the memcpy, and
we can then remove the extra buffer.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarLiang Li <liang.z.li@intel.com>
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Reviewed-by: default avatarAmit Shah <amit.shah@redhat.com>
Message-Id: <1450266458-3178-7-git-send-email-dgilbert@redhat.com>
Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
parent 063e760a

migration/ram.c

+3 −8
Original line number Diff line number Diff line
@@ -286,7 +286,6 @@ static bool quit_comp_thread; 
static bool quit_decomp_thread;

static DecompressParam *decomp_param;

static QemuThread *decompress_threads;

static uint8_t *compressed_data_buf;



static int do_compress_ram_page(CompressParam *param);
@@ -2207,7 +2206,6 @@ void migrate_decompress_threads_create(void) 
    thread_count = migrate_decompress_threads();

    decompress_threads = g_new0(QemuThread, thread_count);

    decomp_param = g_new0(DecompressParam, thread_count);

    compressed_data_buf = g_malloc0(compressBound(TARGET_PAGE_SIZE));

    quit_decomp_thread = false;

    for (i = 0; i < thread_count; i++) {

        qemu_mutex_init(&decomp_param[i].mutex);
@@ -2238,13 +2236,11 @@ void migrate_decompress_threads_join(void) 
    }

    g_free(decompress_threads);

    g_free(decomp_param);

    g_free(compressed_data_buf);

    decompress_threads = NULL;

    decomp_param = NULL;

    compressed_data_buf = NULL;

}



static void decompress_data_with_multi_threads(uint8_t *compbuf,

static void decompress_data_with_multi_threads(QEMUFile *f,

                                               void *host, int len)

{

    int idx, thread_count;
@@ -2253,7 +2249,7 @@ static void decompress_data_with_multi_threads(uint8_t *compbuf, 
    while (true) {

        for (idx = 0; idx < thread_count; idx++) {

            if (!decomp_param[idx].start) {

                memcpy(decomp_param[idx].compbuf, compbuf, len);

                qemu_get_buffer(f, decomp_param[idx].compbuf, len);

                decomp_param[idx].des = host;

                decomp_param[idx].len = len;

                start_decompression(&decomp_param[idx]);
@@ -2498,8 +2494,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) 
                ret = -EINVAL;

                break;

            }

            qemu_get_buffer(f, compressed_data_buf, len);

            decompress_data_with_multi_threads(compressed_data_buf, host, len);

            decompress_data_with_multi_threads(f, host, len);

            break;



        case RAM_SAVE_FLAG_XBZRLE: