From 37ac6bdca826046cbcb0d50727af29baf9407950 Mon Sep 17 00:00:00 2001 From: Anand Avati Date: Fri, 19 Jul 2013 08:31:41 -0700 Subject: storage/posix: implement batched fsync in a single thread Because of the extra fsync()s issued by AFR transaction, they could potentially "clog" all the io-threads denying unrelated operations from making progress. This patch assigns a dedicated thread to issues fsyncs, as an experimental feature to understand performance characteristics with the approach. As a basis, incoming individual fsync requests are grouped into batches, falling in the same @batch-fsync-delay-usec window of time. These windows can extend in practice, as processing of the previous batch can take longer than @batch-fsync-delay-usec while new requests are getting batched. The feature support three modes (similar to the -S modes of fs_mark) - syncfs: In this mode one syncfs() is issued per batch, instead of N fsync()s (one per file.) - syncfs-single-fsync: In this mode one syncfs() is issued per batch (which, on Linux, guarantees the completion of write-out of dirty pages in the filesystem up to that point) and one single fsync() to synchronize or flush the controller/drive cache. This corresponds to -S 2 of fsmark. - syncfs-reverse-fsync: In this mode, one syncfs() is issued per batch, and all the open files in that batch are fsync()'ed in the reverse order of the queue. This corresponds to -S 4 of fsmark. - reverse-fsync: In this mode, no syncfs() is issued and all the files in the batch are fsync()'ed in the reverse order. This corresponds to -S 3 of fsmark. Change-Id: Ia1e170a810c780c8d80e02cf910accc4170c4cd4 BUG: 927146 Signed-off-by: Anand Avati Reviewed-on: http://review.gluster.org/4746 Tested-by: Gluster Build System Reviewed-by: Vijay Bellur --- xlators/cluster/afr/src/afr-transaction.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'xlators/cluster/afr') diff --git a/xlators/cluster/afr/src/afr-transaction.c b/xlators/cluster/afr/src/afr-transaction.c index d6d420910..def00e288 100644 --- a/xlators/cluster/afr/src/afr-transaction.c +++ b/xlators/cluster/afr/src/afr-transaction.c @@ -1478,6 +1478,8 @@ afr_changelog_fsync (call_frame_t *frame, xlator_t *this) int i = 0; int call_count = 0; afr_private_t *priv = NULL; + dict_t *xdata = NULL; + GF_UNUSED int ret = -1; local = frame->local; priv = this->private; @@ -1493,6 +1495,10 @@ afr_changelog_fsync (call_frame_t *frame, xlator_t *this) local->call_count = call_count; + xdata = dict_new(); + if (xdata) + ret = dict_set_int32 (xdata, "batch-fsync", 1); + for (i = 0; i < priv->child_count; i++) { if (!local->transaction.pre_op[i]) continue; @@ -1500,11 +1506,14 @@ afr_changelog_fsync (call_frame_t *frame, xlator_t *this) STACK_WIND_COOKIE (frame, afr_changelog_fsync_cbk, (void *) (long) i, priv->children[i], priv->children[i]->fops->fsync, local->fd, - 1, NULL); + 1, xdata); if (!--call_count) break; } + if (xdata) + dict_unref (xdata); + return 0; } -- cgit