Commit 11c556b3 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

SUNRPC: provide a mechanism for collecting stats in the RPC client 



Add a simple mechanism for collecting stats in the RPC client.  Stats are
tabulated during xprt_release.  Note that per_cpu shenanigans are not
required here because the RPC client already serializes on the transport
write lock.

Test plan:
Compile kernel with CONFIG_NFS enabled.  Basic performance regression
testing with high-speed networking and high performance server.

Signed-off-by: default avatarChuck Lever <cel@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ef759a2e

include/linux/sunrpc/clnt.h

+2 −1
Original line number Diff line number Diff line
@@ -45,7 +45,8 @@ struct rpc_clnt { 
	char *			cl_server;	/* server machine name */

	char *			cl_protname;	/* protocol name */

	struct rpc_auth *	cl_auth;	/* authenticator */

	struct rpc_stat *	cl_stats;	/* statistics */

	struct rpc_stat *	cl_stats;	/* per-program statistics */

	struct rpc_iostats *	cl_metrics;	/* per-client statistics */



	unsigned int		cl_softrtry : 1,/* soft timeouts */

				cl_intr     : 1,/* interruptible */

include/linux/sunrpc/metrics.h

0 → 100644
+77 −0
Original line number Diff line number Diff line 
/*

 *  linux/include/linux/sunrpc/metrics.h

 *

 *  Declarations for RPC client per-operation metrics

 *

 *  Copyright (C) 2005	Chuck Lever <cel@netapp.com>

 *

 *  RPC client per-operation statistics provide latency and retry

 *  information about each type of RPC procedure in a given RPC program.

 *  These statistics are not for detailed problem diagnosis, but simply

 *  to indicate whether the problem is local or remote.

 *

 *  These counters are not meant to be human-readable, but are meant to be

 *  integrated into system monitoring tools such as "sar" and "iostat".  As

 *  such, the counters are sampled by the tools over time, and are never

 *  zeroed after a file system is mounted.  Moving averages can be computed

 *  by the tools by taking the difference between two instantaneous samples

 *  and dividing that by the time between the samples.

 *

 *  The counters are maintained in a single array per RPC client, indexed

 *  by procedure number.  There is no need to maintain separate counter

 *  arrays per-CPU because these counters are always modified behind locks.

 */



#ifndef _LINUX_SUNRPC_METRICS_H

#define _LINUX_SUNRPC_METRICS_H



#include <linux/seq_file.h>



#define RPC_IOSTATS_VERS	"1.0"



struct rpc_iostats {

	/*

	 * These counters give an idea about how many request

	 * transmissions are required, on average, to complete that

	 * particular procedure.  Some procedures may require more

	 * than one transmission because the server is unresponsive,

	 * the client is retransmitting too aggressively, or the

	 * requests are large and the network is congested.

	 */

	unsigned long		om_ops,		/* count of operations */

				om_ntrans,	/* count of RPC transmissions */

				om_timeouts;	/* count of major timeouts */



	/*

	 * These count how many bytes are sent and received for a

	 * given RPC procedure type.  This indicates how much load a

	 * particular procedure is putting on the network.  These

	 * counts include the RPC and ULP headers, and the request

	 * payload.

	 */

	unsigned long long      om_bytes_sent,	/* count of bytes out */

				om_bytes_recv;	/* count of bytes in */



	/*

	 * The length of time an RPC request waits in queue before

	 * transmission, the network + server latency of the request,

	 * and the total time the request spent from init to release

	 * are measured.

	 */

	unsigned long long	om_queue,	/* jiffies queued for xmit */

				om_rtt,		/* jiffies for RPC RTT */

				om_execute;	/* jiffies for RPC execution */

} ____cacheline_aligned;



struct rpc_task;

struct rpc_clnt;



/*

 * EXPORTed functions for managing rpc_iostats structures

 */

struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);

void			rpc_count_iostats(struct rpc_task *);

void			rpc_print_iostats(struct seq_file *, struct rpc_clnt *);

void			rpc_free_iostats(struct rpc_iostats *);



#endif /* _LINUX_SUNRPC_METRICS_H */

net/sunrpc/clnt.c

+6 −3
Original line number Diff line number Diff line
@@ -28,12 +28,11 @@ 
#include <linux/mm.h>

#include <linux/slab.h>

#include <linux/utsname.h>

#include <linux/workqueue.h>



#include <linux/sunrpc/clnt.h>

#include <linux/workqueue.h>

#include <linux/sunrpc/rpc_pipe_fs.h>



#include <linux/nfs.h>

#include <linux/sunrpc/metrics.h>





#define RPC_SLACK_SPACE		(1024)	/* total overkill */
@@ -147,6 +146,7 @@ rpc_new_client(struct rpc_xprt *xprt, char *servname, 
	clnt->cl_vers     = version->number;

	clnt->cl_prot     = xprt->prot;

	clnt->cl_stats    = program->stats;

	clnt->cl_metrics  = rpc_alloc_iostats(clnt);

	rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");



	if (!clnt->cl_port)
@@ -245,6 +245,7 @@ rpc_clone_client(struct rpc_clnt *clnt) 
	if (new->cl_auth)

		atomic_inc(&new->cl_auth->au_count);

	new->cl_pmap		= &new->cl_pmap_default;

	new->cl_metrics         = rpc_alloc_iostats(clnt);

	rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");

	return new;

out_no_clnt:
@@ -315,6 +316,8 @@ rpc_destroy_client(struct rpc_clnt *clnt) 
	if (clnt->cl_server != clnt->cl_inline_name)

		kfree(clnt->cl_server);

out_free:

	rpc_free_iostats(clnt->cl_metrics);

	clnt->cl_metrics = NULL;

	if (clnt->cl_dentry)

		dput(clnt->cl_dentry);

	kfree(clnt);

net/sunrpc/stats.c

+105 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/seq_file.h>

#include <linux/sunrpc/clnt.h>

#include <linux/sunrpc/svcsock.h>

#include <linux/sunrpc/metrics.h>



#define RPCDBG_FACILITY	RPCDBG_MISC
@@ -106,6 +107,110 @@ void svc_seq_show(struct seq_file *seq, const struct svc_stat *statp) { 
	}

}



/**

 * rpc_alloc_iostats - allocate an rpc_iostats structure

 * @clnt: RPC program, version, and xprt

 *

 */

struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt)

{

	unsigned int ops = clnt->cl_maxproc;

	size_t size = ops * sizeof(struct rpc_iostats);

	struct rpc_iostats *new;



	new = kmalloc(size, GFP_KERNEL);

	if (new)

		memset(new, 0 , size);

	return new;

}

EXPORT_SYMBOL(rpc_alloc_iostats);



/**

 * rpc_free_iostats - release an rpc_iostats structure

 * @stats: doomed rpc_iostats structure

 *

 */

void rpc_free_iostats(struct rpc_iostats *stats)

{

	kfree(stats);

}

EXPORT_SYMBOL(rpc_free_iostats);



/**

 * rpc_count_iostats - tally up per-task stats

 * @task: completed rpc_task

 *

 * Relies on the caller for serialization.

 */

void rpc_count_iostats(struct rpc_task *task)

{

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_iostats *stats = task->tk_client->cl_metrics;

	struct rpc_iostats *op_metrics;

	long rtt, execute, queue;



	if (!stats || !req)

		return;

	op_metrics = &stats[task->tk_msg.rpc_proc->p_proc];



	op_metrics->om_ops++;

	op_metrics->om_ntrans += req->rq_ntrans;

	op_metrics->om_timeouts += task->tk_timeouts;



	op_metrics->om_bytes_sent += task->tk_bytes_sent;

	op_metrics->om_bytes_recv += req->rq_received;



	queue = (long)req->rq_xtime - task->tk_start;

	if (queue < 0)

		queue = -queue;

	op_metrics->om_queue += queue;



	rtt = task->tk_rtt;

	if (rtt < 0)

		rtt = -rtt;

	op_metrics->om_rtt += rtt;



	execute = (long)jiffies - task->tk_start;

	if (execute < 0)

		execute = -execute;

	op_metrics->om_execute += execute;

}



#define MILLISECS_PER_JIFFY	(1000UL / HZ)



void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)

{

	struct rpc_iostats *stats = clnt->cl_metrics;

	struct rpc_xprt *xprt = clnt->cl_xprt;

	unsigned int op, maxproc = clnt->cl_maxproc;



	if (!stats)

		return;



	seq_printf(seq, "\tRPC iostats version: %s  ", RPC_IOSTATS_VERS);

	seq_printf(seq, "p/v: %u/%u (%s)\n",

			clnt->cl_prog, clnt->cl_vers, clnt->cl_protname);



	if (xprt)

		xprt->ops->print_stats(xprt, seq);



	seq_printf(seq, "\tper-op statistics\n");

	for (op = 0; op < maxproc; op++) {

		struct rpc_iostats *metrics = &stats[op];

		seq_printf(seq, "%12u: ", op);

		seq_printf(seq, "%lu %lu %lu %Lu %Lu %Lu %Lu %Lu\n",

				metrics->om_ops,

				metrics->om_ntrans,

				metrics->om_timeouts,

				metrics->om_bytes_sent,

				metrics->om_bytes_recv,

				metrics->om_queue * MILLISECS_PER_JIFFY,

				metrics->om_rtt * MILLISECS_PER_JIFFY,

				metrics->om_execute * MILLISECS_PER_JIFFY);

	}

}

EXPORT_SYMBOL(rpc_print_iostats);



/*

 * Register/unregister RPC proc files

 */

net/sunrpc/xprt.c

+2 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include <linux/random.h>



#include <linux/sunrpc/clnt.h>

#include <linux/sunrpc/metrics.h>



/*

 * Local variables
@@ -859,6 +860,7 @@ void xprt_release(struct rpc_task *task) 


	if (!(req = task->tk_rqstp))

		return;

	rpc_count_iostats(task);

	spin_lock_bh(&xprt->transport_lock);

	xprt->ops->release_xprt(xprt, task);

	if (xprt->ops->release_request)