qcow2: add compress threads
Do data compression in separate threads. This significantly improve
performance for qemu-img convert with -W (allow async writes) and -c
(compressed) options.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 9cee653..33b61b7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -44,6 +44,7 @@
#include "qapi/qobject-input-visitor.h"
#include "qapi/qapi-visit-block-core.h"
#include "crypto.h"
+#include "block/thread-pool.h"
/*
Differences with QCOW:
@@ -1544,6 +1545,9 @@
qcow2_check_refcounts(bs, &result, 0);
}
#endif
+
+ qemu_co_queue_init(&s->compress_wait_queue);
+
return ret;
fail:
@@ -3695,6 +3699,62 @@
return ret;
}
+#define MAX_COMPRESS_THREADS 4
+
+typedef struct Qcow2CompressData {
+ void *dest;
+ const void *src;
+ size_t size;
+ ssize_t ret;
+} Qcow2CompressData;
+
+static int qcow2_compress_pool_func(void *opaque)
+{
+ Qcow2CompressData *data = opaque;
+
+ data->ret = qcow2_compress(data->dest, data->src, data->size);
+
+ return 0;
+}
+
+static void qcow2_compress_complete(void *opaque, int ret)
+{
+ qemu_coroutine_enter(opaque);
+}
+
+/* See qcow2_compress definition for parameters description */
+static ssize_t qcow2_co_compress(BlockDriverState *bs,
+ void *dest, const void *src, size_t size)
+{
+ BDRVQcow2State *s = bs->opaque;
+ BlockAIOCB *acb;
+ ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
+ Qcow2CompressData arg = {
+ .dest = dest,
+ .src = src,
+ .size = size,
+ };
+
+ while (s->nb_compress_threads >= MAX_COMPRESS_THREADS) {
+ qemu_co_queue_wait(&s->compress_wait_queue, NULL);
+ }
+
+ s->nb_compress_threads++;
+ acb = thread_pool_submit_aio(pool, qcow2_compress_pool_func, &arg,
+ qcow2_compress_complete,
+ qemu_coroutine_self());
+
+ if (!acb) {
+ s->nb_compress_threads--;
+ return -EINVAL;
+ }
+ qemu_coroutine_yield();
+ s->nb_compress_threads--;
+ qemu_co_queue_next(&s->compress_wait_queue);
+
+ return arg.ret;
+}
+
/* XXX: put compressed sectors first, then all the cluster aligned
tables to avoid losing bytes in alignment */
static coroutine_fn int
@@ -3739,7 +3799,7 @@
out_buf = g_malloc(s->cluster_size);
- out_len = qcow2_compress(out_buf, buf, s->cluster_size);
+ out_len = qcow2_co_compress(bs, out_buf, buf, s->cluster_size);
if (out_len == -2) {
ret = -EINVAL;
goto fail;
