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Commit 3289025a authored by Santosh Shilimkar's avatar Santosh Shilimkar
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RDS: add receive message trace used by application 



Socket option to tap receive path latency in various stages
in nano seconds. It can be enabled on selective sockets using
using SO_RDS_MSG_RXPATH_LATENCY socket option. RDS will return
the data to application with RDS_CMSG_RXPATH_LATENCY in defined
format. Scope is left to add more trace points for future
without need of change in the interface.

Reviewed-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@oracle.com>
parent f9fb69ad

include/uapi/linux/rds.h

+33 −0
Original line number Diff line number Diff line
@@ -52,6 +52,13 @@ 
#define RDS_GET_MR_FOR_DEST		7

#define SO_RDS_TRANSPORT		8



/* Socket option to tap receive path latency

 *	SO_RDS: SO_RDS_MSG_RXPATH_LATENCY

 *	Format used struct rds_rx_trace_so

 */

#define SO_RDS_MSG_RXPATH_LATENCY	10





/* supported values for SO_RDS_TRANSPORT */

#define	RDS_TRANS_IB	0

#define	RDS_TRANS_IWARP	1
@@ -77,6 +84,12 @@ 
 *	the same as for the GET_MR setsockopt.

 * RDS_CMSG_RDMA_STATUS (recvmsg)

 *	Returns the status of a completed RDMA operation.

 * RDS_CMSG_RXPATH_LATENCY(recvmsg)

 *	Returns rds message latencies in various stages of receive

 *	path in nS. Its set per socket using SO_RDS_MSG_RXPATH_LATENCY

 *	socket option. Legitimate points are defined in

 *	enum rds_message_rxpath_latency. More points can be added in

 *	future. CSMG format is struct rds_cmsg_rx_trace.

 */

#define RDS_CMSG_RDMA_ARGS		1

#define RDS_CMSG_RDMA_DEST		2
@@ -87,6 +100,7 @@ 
#define RDS_CMSG_ATOMIC_CSWP		7

#define RDS_CMSG_MASKED_ATOMIC_FADD	8

#define RDS_CMSG_MASKED_ATOMIC_CSWP	9

#define RDS_CMSG_RXPATH_LATENCY		11



#define RDS_INFO_FIRST			10000

#define RDS_INFO_COUNTERS		10000
@@ -171,6 +185,25 @@ struct rds_info_rdma_connection { 
	uint32_t	rdma_mr_size;

};



/* RDS message Receive Path Latency points */

enum rds_message_rxpath_latency {

	RDS_MSG_RX_HDR_TO_DGRAM_START = 0,

	RDS_MSG_RX_DGRAM_REASSEMBLE,

	RDS_MSG_RX_DGRAM_DELIVERED,

	RDS_MSG_RX_DGRAM_TRACE_MAX

};



struct rds_rx_trace_so {

	u8 rx_traces;

	u8 rx_trace_pos[RDS_MSG_RX_DGRAM_TRACE_MAX];

};



struct rds_cmsg_rx_trace {

	u8 rx_traces;

	u8 rx_trace_pos[RDS_MSG_RX_DGRAM_TRACE_MAX];

	u64 rx_trace[RDS_MSG_RX_DGRAM_TRACE_MAX];

};



/*

 * Congestion monitoring.

 * Congestion control in RDS happens at the host connection

net/rds/af_rds.c

+28 −0
Original line number Diff line number Diff line
@@ -298,6 +298,30 @@ static int rds_enable_recvtstamp(struct sock *sk, char __user *optval, 
	return 0;

}



static int rds_recv_track_latency(struct rds_sock *rs, char __user *optval,

				  int optlen)

{

	struct rds_rx_trace_so trace;

	int i;



	if (optlen != sizeof(struct rds_rx_trace_so))

		return -EFAULT;



	if (copy_from_user(&trace, optval, sizeof(trace)))

		return -EFAULT;



	rs->rs_rx_traces = trace.rx_traces;

	for (i = 0; i < rs->rs_rx_traces; i++) {

		if (trace.rx_trace_pos[i] > RDS_MSG_RX_DGRAM_TRACE_MAX) {

			rs->rs_rx_traces = 0;

			return -EFAULT;

		}

		rs->rs_rx_trace[i] = trace.rx_trace_pos[i];

	}



	return 0;

}



static int rds_setsockopt(struct socket *sock, int level, int optname,

			  char __user *optval, unsigned int optlen)

{
@@ -338,6 +362,9 @@ static int rds_setsockopt(struct socket *sock, int level, int optname, 
		ret = rds_enable_recvtstamp(sock->sk, optval, optlen);

		release_sock(sock->sk);

		break;

	case SO_RDS_MSG_RXPATH_LATENCY:

		ret = rds_recv_track_latency(rs, optval, optlen);

		break;

	default:

		ret = -ENOPROTOOPT;

	}
@@ -484,6 +511,7 @@ static int __rds_create(struct socket *sock, struct sock *sk, int protocol) 
	INIT_LIST_HEAD(&rs->rs_cong_list);

	spin_lock_init(&rs->rs_rdma_lock);

	rs->rs_rdma_keys = RB_ROOT;

	rs->rs_rx_traces = 0;



	spin_lock_bh(&rds_sock_lock);

	list_add_tail(&rs->rs_item, &rds_sock_list);

net/rds/ib_recv.c

+4 −0
Original line number Diff line number Diff line
@@ -911,8 +911,12 @@ static void rds_ib_process_recv(struct rds_connection *conn, 
		ic->i_ibinc = ibinc;



		hdr = &ibinc->ii_inc.i_hdr;

		ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =

				local_clock();

		memcpy(hdr, ihdr, sizeof(*hdr));

		ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);

		ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_START] =

				local_clock();



		rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,

			 ic->i_recv_data_rem, hdr->h_flags);

net/rds/rds.h

+10 −0
Original line number Diff line number Diff line
@@ -253,6 +253,11 @@ struct rds_ext_header_rdma_dest { 
#define RDS_EXTHDR_GEN_NUM	6



#define __RDS_EXTHDR_MAX	16 /* for now */

#define RDS_RX_MAX_TRACES	(RDS_MSG_RX_DGRAM_TRACE_MAX + 1)

#define	RDS_MSG_RX_HDR		0

#define	RDS_MSG_RX_START	1

#define	RDS_MSG_RX_END		2

#define	RDS_MSG_RX_CMSG		3



struct rds_incoming {

	atomic_t		i_refcount;
@@ -265,6 +270,7 @@ struct rds_incoming { 


	rds_rdma_cookie_t	i_rdma_cookie;

	struct timeval		i_rx_tstamp;

	u64			i_rx_lat_trace[RDS_RX_MAX_TRACES];

};



struct rds_mr {
@@ -575,6 +581,10 @@ struct rds_sock { 
	unsigned char		rs_recverr,

				rs_cong_monitor;

	u32			rs_hash_initval;



	/* Socket receive path trace points*/

	u8			rs_rx_traces;

	u8			rs_rx_trace[RDS_MSG_RX_DGRAM_TRACE_MAX];

};



static inline struct rds_sock *rds_sk_to_rs(const struct sock *sk)

net/rds/recv.c

+29 −3
Original line number Diff line number Diff line
@@ -43,6 +43,8 @@ 
void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,

		  __be32 saddr)

{

	int i;



	atomic_set(&inc->i_refcount, 1);

	INIT_LIST_HEAD(&inc->i_item);

	inc->i_conn = conn;
@@ -50,6 +52,9 @@ void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn, 
	inc->i_rdma_cookie = 0;

	inc->i_rx_tstamp.tv_sec = 0;

	inc->i_rx_tstamp.tv_usec = 0;



	for (i = 0; i < RDS_RX_MAX_TRACES; i++)

		inc->i_rx_lat_trace[i] = 0;

}

EXPORT_SYMBOL_GPL(rds_inc_init);
@@ -373,6 +378,7 @@ void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr, 
		if (sock_flag(sk, SOCK_RCVTSTAMP))

			do_gettimeofday(&inc->i_rx_tstamp);

		rds_inc_addref(inc);

		inc->i_rx_lat_trace[RDS_MSG_RX_END] = local_clock();

		list_add_tail(&inc->i_item, &rs->rs_recv_queue);

		__rds_wake_sk_sleep(sk);

	} else {
@@ -534,7 +540,7 @@ static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg, 
		ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,

				sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);

		if (ret)

			return ret;

			goto out;

	}



	if ((inc->i_rx_tstamp.tv_sec != 0) &&
@@ -543,10 +549,30 @@ static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg, 
			       sizeof(struct timeval),

			       &inc->i_rx_tstamp);

		if (ret)

			return ret;

			goto out;

	}



	return 0;

	if (rs->rs_rx_traces) {

		struct rds_cmsg_rx_trace t;

		int i, j;



		inc->i_rx_lat_trace[RDS_MSG_RX_CMSG] = local_clock();

		t.rx_traces =  rs->rs_rx_traces;

		for (i = 0; i < rs->rs_rx_traces; i++) {

			j = rs->rs_rx_trace[i];

			t.rx_trace_pos[i] = j;

			t.rx_trace[i] = inc->i_rx_lat_trace[j + 1] -

					  inc->i_rx_lat_trace[j];

		}



		ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RXPATH_LATENCY,

			       sizeof(t), &t);

		if (ret)

			goto out;

	}



out:

	return ret;

}



int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,