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authorAnand Avati <avati@redhat.com>2013-07-19 08:31:41 -0700
committerVijay Bellur <vbellur@redhat.com>2013-07-23 06:11:12 -0700
commit37ac6bdca826046cbcb0d50727af29baf9407950 (patch)
treeb899eb81a70c7719c5d7e4328697cc314da24b97 /xlators/cluster/afr
parentcee1f9b5c7917bba220f1156b342bf07cac4ad38 (diff)
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 <avati@redhat.com> Reviewed-on: http://review.gluster.org/4746 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Diffstat (limited to 'xlators/cluster/afr')
-rw-r--r--xlators/cluster/afr/src/afr-transaction.c11
1 files changed, 10 insertions, 1 deletions
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;
}