Hi Bruce! Here are the patches that I had mentioned earlier that reduce the contention for the pool->sp_lock when the server is heavily loaded. The basic problem is that whenever a svc_xprt needs to be queued up for servicing, we have to take the pool->sp_lock to try and find an idle thread to service it. On a busy server, that lock becomes highly contended and that limits the throughput. This patchset fixes this by changing how we search for an idle thread. First, we convert svc_rqst and the sp_all_threads list to be RCU-managed. Then we change the search for an idle thread to use the sp_all_threads list, which now can be done under the rcu_read_lock. When there is an available thread, queueing an xprt to it can now be done without any spinlocking. With this, we see a pretty substantial increase in performance on a larger-scale server that is heavily loaded. Chris has some preliminary numbers, but they need to be cleaned up a bit before we can present them. I'm hoping to have those by early next week. Jeff Layton (4): sunrpc: add a rcu_head to svc_rqst and use kfree_rcu to free it sunrpc: fix potential races in pool_stats collection sunrpc: convert to lockless lookup of queued server threads sunrpc: add some tracepoints around enqueue and dequeue of svc_xprt include/linux/sunrpc/svc.h | 12 +- include/trace/events/sunrpc.h | 98 +++++++++++++++- net/sunrpc/svc.c | 17 +-- net/sunrpc/svc_xprt.c | 252 ++++++++++++++++++++++++------------------ 4 files changed, 258 insertions(+), 121 deletions(-) -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
