Andreas Bluemle observed an undesirable behavior in the ceph
messenger when using networking hardware that binds received data
handling to a single CPU. The messenger uses a workqueue to process
message activity, and in this case all work was being queued on the
same per-cpu workqueue. Consequently that CPU becomes a bottleneck,
forced to process all incoming messages.
Marking the workqueue UNBOUND allows any available CPU to process a
work item on the queue. The concurrency of the workqueue will be
limited by the number of active connections.
Reported-by: Andreas Bluemle <andreas.bluemle@xxxxxxxxxxx>
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
net/ceph/messenger.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 28ed904..f9f65fe 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -190,7 +190,7 @@ int ceph_msgr_init(void)
zero_page = ZERO_PAGE(0);
page_cache_get(zero_page);
- ceph_msgr_wq = alloc_workqueue("ceph-msgr", 0, 0);
+ ceph_msgr_wq = alloc_workqueue("ceph-msgr", WQ_UNBOUND, 0);
if (ceph_msgr_wq)
return 0;
--
1.7.9.5
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