From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47172) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ccj7u-0006zs-M8 for qemu-devel@nongnu.org; Sat, 11 Feb 2017 20:38:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ccj7t-0007Ij-IX for qemu-devel@nongnu.org; Sat, 11 Feb 2017 20:38:54 -0500 From: Max Reitz Date: Sun, 12 Feb 2017 02:38:34 +0100 Message-Id: <20170212013844.6560-2-mreitz@redhat.com> In-Reply-To: <20170212013440.5919-1-mreitz@redhat.com> References: <20170212013440.5919-1-mreitz@redhat.com> Subject: [Qemu-devel] [PULL 11/21] block/qapi: reduce the execution time of qmp_query_blockstats List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Max Reitz , Peter Maydell From: Dou Liyang In order to reduce the execution time, this patch optimize the qmp_query_blockstats(): Remove the next_query_bds function. Remove the bdrv_query_stats function. Remove some judgement sentence. The original qmp_query_blockstats calls next_query_bds to get the next objects in each loops. In the next_query_bds, it checks the query_nodes and blk. It also call bdrv_query_stats to get the stats, In the bdrv_query_stats, it checks blk and bs each times. This waste more times, which may stall the main loop a bit. And if the disk is too many and donot use the dataplane feature, this may affect the performance in main loop thread. This patch removes that two functions, and makes the structure clearly. Signed-off-by: Dou Liyang Message-id: 1484467275-27919-3-git-send-email-douly.fnst@cn.fujitsu.com Reviewed-by: Markus Armbruster [mreitz: Removed duplicate info->value assignment] Signed-off-by: Max Reitz --- block/qapi.c | 73 ++++++++++++++++++++++++------------------------------------ 1 file changed, 29 insertions(+), 44 deletions(-) diff --git a/block/qapi.c b/block/qapi.c index 48105ed277..ac480aa93c 100644 --- a/block/qapi.c +++ b/block/qapi.c @@ -456,23 +456,6 @@ static BlockStats *bdrv_query_bds_stats(const BlockDriverState *bs, return s; } -static BlockStats *bdrv_query_stats(BlockBackend *blk, - const BlockDriverState *bs, - bool query_backing) -{ - BlockStats *s; - - s = bdrv_query_bds_stats(bs, query_backing); - - if (blk) { - s->has_device = true; - s->device = g_strdup(blk_name(blk)); - bdrv_query_blk_stats(s->stats, blk); - } - - return s; -} - BlockInfoList *qmp_query_block(Error **errp) { BlockInfoList *head = NULL, **p_next = &head; @@ -496,42 +479,44 @@ BlockInfoList *qmp_query_block(Error **errp) return head; } -static bool next_query_bds(BlockBackend **blk, BlockDriverState **bs, - bool query_nodes) -{ - if (query_nodes) { - *bs = bdrv_next_node(*bs); - return !!*bs; - } - - *blk = blk_next(*blk); - *bs = *blk ? blk_bs(*blk) : NULL; - - return !!*blk; -} - BlockStatsList *qmp_query_blockstats(bool has_query_nodes, bool query_nodes, Error **errp) { BlockStatsList *head = NULL, **p_next = &head; - BlockBackend *blk = NULL; - BlockDriverState *bs = NULL; + BlockBackend *blk; + BlockDriverState *bs; /* Just to be safe if query_nodes is not always initialized */ - query_nodes = has_query_nodes && query_nodes; - - while (next_query_bds(&blk, &bs, query_nodes)) { - BlockStatsList *info = g_malloc0(sizeof(*info)); - AioContext *ctx = blk ? blk_get_aio_context(blk) - : bdrv_get_aio_context(bs); + if (has_query_nodes && query_nodes) { + for (bs = bdrv_next_node(NULL); bs; bs = bdrv_next_node(bs)) { + BlockStatsList *info = g_malloc0(sizeof(*info)); + AioContext *ctx = bdrv_get_aio_context(bs); - aio_context_acquire(ctx); - info->value = bdrv_query_stats(blk, bs, !query_nodes); - aio_context_release(ctx); + aio_context_acquire(ctx); + info->value = bdrv_query_bds_stats(bs, false); + aio_context_release(ctx); - *p_next = info; - p_next = &info->next; + *p_next = info; + p_next = &info->next; + } + } else { + for (blk = blk_next(NULL); blk; blk = blk_next(blk)) { + BlockStatsList *info = g_malloc0(sizeof(*info)); + AioContext *ctx = blk_get_aio_context(blk); + BlockStats *s; + + aio_context_acquire(ctx); + s = bdrv_query_bds_stats(blk_bs(blk), true); + s->has_device = true; + s->device = g_strdup(blk_name(blk)); + bdrv_query_blk_stats(s->stats, blk); + aio_context_release(ctx); + + info->value = s; + *p_next = info; + p_next = &info->next; + } } return head; -- 2.11.0