> On Mar 6, 2018, at 5:02 PM, Anna Schumaker <Anna.Schumaker@xxxxxxxxxx> wrote:
>
> Hi Chuck,
>
> I'm seeing a huge performance hit with this patch. I'm just running cthon over TCP, and it goes from finishing in 22 seconds to taking well over 5 minutes. I seem to only see this on the read and write tests, such as basic test5 taking a minute to finish:
>
> ./test5: read and write
> wrote 1048576 byte file 10 times in 60.35 seconds (173737 bytes/sec)
> read 1048576 byte file 10 times in 0.0 seconds (-2147483648 bytes/sec)
> ./test5 ok.
OK. This looks like write is impacted, but this test doesn't
actually perform any reads on the wire. Try iozone with -I,
maybe? That would show results for both read and write.
> I haven't dug into this too deeply, but my best guess is that maybe it's due to adding a call to xprt_request_init() in net/sunrpc/clnt.c:call_reserveresult()
It wasn't added there, it was moved from xprt_alloc_slot. So,
it's not new work per-RPC.
Any additional information would be appreciated!
> Thoughts?
> Anna
>
> On 03/05/2018 03:13 PM, Chuck Lever wrote:
>> alloc_slot is a transport-specific op, but initializing an rpc_rqst
>> is common to all transports. Move initialization to common code in
>> preparation for adding a transport-specific alloc_slot to xprtrdma.
>>
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> ---
>> include/linux/sunrpc/xprt.h | 1 +
>> net/sunrpc/clnt.c | 1 +
>> net/sunrpc/xprt.c | 12 +++++++-----
>> 3 files changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
>> index 5fea0fb..9784e28 100644
>> --- a/include/linux/sunrpc/xprt.h
>> +++ b/include/linux/sunrpc/xprt.h
>> @@ -324,6 +324,7 @@ struct xprt_class {
>> struct rpc_xprt *xprt_create_transport(struct xprt_create *args);
>> void xprt_connect(struct rpc_task *task);
>> void xprt_reserve(struct rpc_task *task);
>> +void xprt_request_init(struct rpc_task *task);
>> void xprt_retry_reserve(struct rpc_task *task);
>> int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
>> int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
>> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
>> index 6e432ec..226f558 100644
>> --- a/net/sunrpc/clnt.c
>> +++ b/net/sunrpc/clnt.c
>> @@ -1546,6 +1546,7 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
>> task->tk_status = 0;
>> if (status >= 0) {
>> if (task->tk_rqstp) {
>> + xprt_request_init(task);
>> task->tk_action = call_refresh;
>> return;
>> }
>> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
>> index 70f0050..a394b46 100644
>> --- a/net/sunrpc/xprt.c
>> +++ b/net/sunrpc/xprt.c
>> @@ -66,7 +66,7 @@
>> * Local functions
>> */
>> static void xprt_init(struct rpc_xprt *xprt, struct net *net);
>> -static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
>> +static __be32 xprt_alloc_xid(struct rpc_xprt *xprt);
>> static void xprt_connect_status(struct rpc_task *task);
>> static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
>> static void __xprt_put_cong(struct rpc_xprt *, struct rpc_rqst *);
>> @@ -987,6 +987,8 @@ bool xprt_prepare_transmit(struct rpc_task *task)
>> task->tk_status = -EAGAIN;
>> goto out_unlock;
>> }
>> + if (likely(!bc_prealloc(req)))
>> + req->rq_xid = xprt_alloc_xid(xprt);
>> ret = true;
>> out_unlock:
>> spin_unlock_bh(&xprt->transport_lock);
>> @@ -1163,10 +1165,10 @@ void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
>> out_init_req:
>> xprt->stat.max_slots = max_t(unsigned int, xprt->stat.max_slots,
>> xprt->num_reqs);
>> + spin_unlock(&xprt->reserve_lock);
>> +
>> task->tk_status = 0;
>> task->tk_rqstp = req;
>> - xprt_request_init(task, xprt);
>> - spin_unlock(&xprt->reserve_lock);
>> }
>> EXPORT_SYMBOL_GPL(xprt_alloc_slot);
>>
>> @@ -1303,8 +1305,9 @@ static inline void xprt_init_xid(struct rpc_xprt *xprt)
>> xprt->xid = prandom_u32();
>> }
>>
>> -static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
>> +void xprt_request_init(struct rpc_task *task)
>> {
>> + struct rpc_xprt *xprt = task->tk_xprt;
>> struct rpc_rqst *req = task->tk_rqstp;
>>
>> INIT_LIST_HEAD(&req->rq_list);
>> @@ -1312,7 +1315,6 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
>> req->rq_task = task;
>> req->rq_xprt = xprt;
>> req->rq_buffer = NULL;
>> - req->rq_xid = xprt_alloc_xid(xprt);
>> req->rq_connect_cookie = xprt->connect_cookie - 1;
>> req->rq_bytes_sent = 0;
>> req->rq_snd_buf.len = 0;
>>
--
Chuck Lever
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