Implement the basic round trip timing algorithm in order to adapt the
timeout values for the most common NFS operations to the server's
rate of response.
Algorithm is described in Van Jacobson's paper 1998 paper
on http://www-nrg.ee.lbl.gov/nrg-papers.html, and is the same as is
used for most TCP stacks.
Following the *BSD code, we implement separate rtt timers for GETATTR,
LOOKUP, READ/READDIR/READLINK, and WRITE. In addition to this, there
is one extra timer for the COMMIT operation.
All the remaining RPC calls use the current system in which a fixed
timeout value gets set by the 'timeo' mount option.
In case of a timeout, the current exponential backoff algoritm is
implemented. Subsequent patches will improve this...
Cheers,
Trond
diff -u --recursive --new-file linux-2.5.25/fs/lockd/xdr.c linux-2.5.25-rtt1/fs/lockd/xdr.c
--- linux-2.5.25/fs/lockd/xdr.c Mon Feb 25 19:35:33 2002
+++ linux-2.5.25-rtt1/fs/lockd/xdr.c Tue Jul 16 11:43:08 2002
@@ -561,11 +561,10 @@
#define nlmclt_decode_norep NULL
#define PROC(proc, argtype, restype) \
- { "nlm_" #proc, \
- (kxdrproc_t) nlmclt_encode_##argtype, \
- (kxdrproc_t) nlmclt_decode_##restype, \
- MAX(NLM_##argtype##_sz, NLM_##restype##_sz) << 2, \
- 0 \
+ { .p_procname = "nlm_" #proc, \
+ .p_encode = (kxdrproc_t) nlmclt_encode_##argtype, \
+ .p_decode = (kxdrproc_t) nlmclt_decode_##restype, \
+ .p_bufsiz = MAX(NLM_##argtype##_sz, NLM_##restype##_sz) << 2 \
}
static struct rpc_procinfo nlm_procedures[] = {
diff -u --recursive --new-file linux-2.5.25/fs/lockd/xdr4.c linux-2.5.25-rtt1/fs/lockd/xdr4.c
--- linux-2.5.25/fs/lockd/xdr4.c Mon Feb 25 19:35:33 2002
+++ linux-2.5.25-rtt1/fs/lockd/xdr4.c Tue Jul 16 11:43:08 2002
@@ -566,12 +566,11 @@
*/
#define nlm4clt_decode_norep NULL
-#define PROC(proc, argtype, restype) \
- { "nlm4_" #proc, \
- (kxdrproc_t) nlm4clt_encode_##argtype, \
- (kxdrproc_t) nlm4clt_decode_##restype, \
- MAX(NLM4_##argtype##_sz, NLM4_##restype##_sz) << 2, \
- 0 \
+#define PROC(proc, argtype, restype) \
+ { .p_procname = "nlm4_" #proc, \
+ .p_encode = (kxdrproc_t) nlm4clt_encode_##argtype, \
+ .p_decode = (kxdrproc_t) nlm4clt_decode_##restype, \
+ .p_bufsiz = MAX(NLM4_##argtype##_sz, NLM4_##restype##_sz) << 2 \
}
static struct rpc_procinfo nlm4_procedures[] = {
diff -u --recursive --new-file linux-2.5.25/fs/nfs/nfs2xdr.c linux-2.5.25-rtt1/fs/nfs/nfs2xdr.c
--- linux-2.5.25/fs/nfs/nfs2xdr.c Sat May 25 21:34:59 2002
+++ linux-2.5.25-rtt1/fs/nfs/nfs2xdr.c Tue Jul 16 11:43:08 2002
@@ -671,33 +671,32 @@
# define MAX(a, b) (((a) > (b))? (a) : (b))
#endif
-#define PROC(proc, argtype, restype) \
- { "nfs_" #proc, \
- (kxdrproc_t) nfs_xdr_##argtype, \
- (kxdrproc_t) nfs_xdr_##restype, \
- MAX(NFS_##argtype##_sz,NFS_##restype##_sz) << 2, \
- 0 \
+#define PROC(proc, argtype, restype, timer) \
+ { .p_procname = "nfs_" #proc, \
+ .p_encode = (kxdrproc_t) nfs_xdr_##argtype, \
+ .p_decode = (kxdrproc_t) nfs_xdr_##restype, \
+ .p_bufsiz = MAX(NFS_##argtype##_sz,NFS_##restype##_sz) << 2, \
+ .p_timer = timer \
}
-
static struct rpc_procinfo nfs_procedures[18] = {
- PROC(null, enc_void, dec_void),
- PROC(getattr, fhandle, attrstat),
- PROC(setattr, sattrargs, attrstat),
- PROC(root, enc_void, dec_void),
- PROC(lookup, diropargs, diropres),
- PROC(readlink, readlinkargs, readlinkres),
- PROC(read, readargs, readres),
- PROC(writecache, enc_void, dec_void),
- PROC(write, writeargs, writeres),
- PROC(create, createargs, diropres),
- PROC(remove, diropargs, stat),
- PROC(rename, renameargs, stat),
- PROC(link, linkargs, stat),
- PROC(symlink, symlinkargs, stat),
- PROC(mkdir, createargs, diropres),
- PROC(rmdir, diropargs, stat),
- PROC(readdir, readdirargs, readdirres),
- PROC(statfs, fhandle, statfsres),
+ PROC(null, enc_void, dec_void, 0),
+ PROC(getattr, fhandle, attrstat, 1),
+ PROC(setattr, sattrargs, attrstat, 0),
+ PROC(root, enc_void, dec_void, 0),
+ PROC(lookup, diropargs, diropres, 2),
+ PROC(readlink, readlinkargs, readlinkres, 3),
+ PROC(read, readargs, readres, 3),
+ PROC(writecache, enc_void, dec_void, 0),
+ PROC(write, writeargs, writeres, 4),
+ PROC(create, createargs, diropres, 0),
+ PROC(remove, diropargs, stat, 0),
+ PROC(rename, renameargs, stat, 0),
+ PROC(link, linkargs, stat, 0),
+ PROC(symlink, symlinkargs, stat, 0),
+ PROC(mkdir, createargs, diropres, 0),
+ PROC(rmdir, diropargs, stat, 0),
+ PROC(readdir, readdirargs, readdirres, 3),
+ PROC(statfs, fhandle, statfsres, 0),
};
struct rpc_version nfs_version2 = {
diff -u --recursive --new-file linux-2.5.25/fs/nfs/nfs3xdr.c linux-2.5.25-rtt1/fs/nfs/nfs3xdr.c
--- linux-2.5.25/fs/nfs/nfs3xdr.c Sat May 25 21:25:56 2002
+++ linux-2.5.25-rtt1/fs/nfs/nfs3xdr.c Tue Jul 16 11:43:08 2002
@@ -988,37 +988,37 @@
# define MAX(a, b) (((a) > (b))? (a) : (b))
#endif
-#define PROC(proc, argtype, restype) \
- { "nfs3_" #proc, \
- (kxdrproc_t) nfs3_xdr_##argtype, \
- (kxdrproc_t) nfs3_xdr_##restype, \
- MAX(NFS3_##argtype##_sz,NFS3_##restype##_sz) << 2, \
- 0 \
+#define PROC(proc, argtype, restype, timer) \
+ { .p_procname = "nfs3_" #proc, \
+ .p_encode = (kxdrproc_t) nfs3_xdr_##argtype, \
+ .p_decode = (kxdrproc_t) nfs3_xdr_##restype, \
+ .p_bufsiz = MAX(NFS3_##argtype##_sz,NFS3_##restype##_sz) << 2, \
+ .p_timer = timer \
}
static struct rpc_procinfo nfs3_procedures[22] = {
- PROC(null, enc_void, dec_void),
- PROC(getattr, fhandle, attrstat),
- PROC(setattr, sattrargs, wccstat),
- PROC(lookup, diropargs, lookupres),
- PROC(access, accessargs, accessres),
- PROC(readlink, readlinkargs, readlinkres),
- PROC(read, readargs, readres),
- PROC(write, writeargs, writeres),
- PROC(create, createargs, createres),
- PROC(mkdir, mkdirargs, createres),
- PROC(symlink, symlinkargs, createres),
- PROC(mknod, mknodargs, createres),
- PROC(remove, diropargs, wccstat),
- PROC(rmdir, diropargs, wccstat),
- PROC(rename, renameargs, renameres),
- PROC(link, linkargs, linkres),
- PROC(readdir, readdirargs, readdirres),
- PROC(readdirplus, readdirargs, readdirres),
- PROC(fsstat, fhandle, fsstatres),
- PROC(fsinfo, fhandle, fsinfores),
- PROC(pathconf, fhandle, pathconfres),
- PROC(commit, commitargs, commitres),
+ PROC(null, enc_void, dec_void, 0),
+ PROC(getattr, fhandle, attrstat, 1),
+ PROC(setattr, sattrargs, wccstat, 0),
+ PROC(lookup, diropargs, lookupres, 2),
+ PROC(access, accessargs, accessres, 1),
+ PROC(readlink, readlinkargs, readlinkres, 3),
+ PROC(read, readargs, readres, 3),
+ PROC(write, writeargs, writeres, 4),
+ PROC(create, createargs, createres, 0),
+ PROC(mkdir, mkdirargs, createres, 0),
+ PROC(symlink, symlinkargs, createres, 0),
+ PROC(mknod, mknodargs, createres, 0),
+ PROC(remove, diropargs, wccstat, 0),
+ PROC(rmdir, diropargs, wccstat, 0),
+ PROC(rename, renameargs, renameres, 0),
+ PROC(link, linkargs, linkres, 0),
+ PROC(readdir, readdirargs, readdirres, 3),
+ PROC(readdirplus, readdirargs, readdirres, 3),
+ PROC(fsstat, fhandle, fsstatres, 0),
+ PROC(fsinfo, fhandle, fsinfores, 0),
+ PROC(pathconf, fhandle, pathconfres, 0),
+ PROC(commit, commitargs, commitres, 5),
};
struct rpc_version nfs_version3 = {
diff -u --recursive --new-file linux-2.5.25/include/linux/sunrpc/clnt.h linux-2.5.25-rtt1/include/linux/sunrpc/clnt.h
--- linux-2.5.25/include/linux/sunrpc/clnt.h Tue Feb 5 16:23:43 2002
+++ linux-2.5.25-rtt1/include/linux/sunrpc/clnt.h Tue Jul 16 11:44:28 2002
@@ -15,6 +15,7 @@
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/xdr.h>
+#include <linux/sunrpc/timer.h>
#include <asm/signal.h>
/*
@@ -52,6 +53,8 @@
unsigned int cl_flags; /* misc client flags */
unsigned long cl_hardmax; /* max hard timeout */
+ struct rpc_rtt cl_rtt; /* RTO estimator data */
+
struct rpc_portmap cl_pmap; /* port mapping */
struct rpc_wait_queue cl_bindwait; /* waiting on getport() */
@@ -91,6 +94,7 @@
kxdrproc_t p_decode; /* XDR decode function */
unsigned int p_bufsiz; /* req. buffer size */
unsigned int p_count; /* call count */
+ unsigned int p_timer; /* Which RTT timer to use */
};
#define rpcproc_bufsiz(clnt, proc) ((clnt)->cl_procinfo[proc].p_bufsiz)
@@ -98,6 +102,7 @@
#define rpcproc_decode(clnt, proc) ((clnt)->cl_procinfo[proc].p_decode)
#define rpcproc_name(clnt, proc) ((clnt)->cl_procinfo[proc].p_procname)
#define rpcproc_count(clnt, proc) ((clnt)->cl_procinfo[proc].p_count)
+#define rpcproc_timer(clnt, proc) ((clnt)->cl_procinfo[proc].p_timer)
#define RPC_CONGESTED(clnt) (RPCXPRT_CONGESTED((clnt)->cl_xprt))
#define RPC_PEERADDR(clnt) (&(clnt)->cl_xprt->addr)
diff -u --recursive --new-file linux-2.5.25/include/linux/sunrpc/timer.h linux-2.5.25-rtt1/include/linux/sunrpc/timer.h
--- linux-2.5.25/include/linux/sunrpc/timer.h Thu Jan 1 01:00:00 1970
+++ linux-2.5.25-rtt1/include/linux/sunrpc/timer.h Tue Jul 16 11:43:08 2002
@@ -0,0 +1,23 @@
+/*
+ * linux/include/linux/sunrpc/timer.h
+ *
+ * Declarations for the RPC transport timer.
+ *
+ * Copyright (C) 2002 Trond Myklebust <trond.myklebust@fys.uio.no>
+ */
+
+#ifndef _LINUX_SUNRPC_TIMER_H
+#define _LINUX_SUNRPC_TIMER_H
+
+struct rpc_rtt {
+ long timeo; /* default timeout value */
+ long srtt[5]; /* smoothed round trip time << 3 */
+ long sdrtt[5]; /* soothed medium deviation of RTT */
+};
+
+
+extern void rpc_init_rtt(struct rpc_rtt *rt, long timeo);
+extern void rpc_update_rtt(struct rpc_rtt *rt, int timer, long m);
+extern long rpc_calc_rto(struct rpc_rtt *rt, int timer);
+
+#endif /* _LINUX_SUNRPC_TIMER_H */
diff -u --recursive --new-file linux-2.5.25/include/linux/sunrpc/xprt.h linux-2.5.25-rtt1/include/linux/sunrpc/xprt.h
--- linux-2.5.25/include/linux/sunrpc/xprt.h Sun Jul 7 19:43:16 2002
+++ linux-2.5.25-rtt1/include/linux/sunrpc/xprt.h Tue Jul 16 11:43:08 2002
@@ -98,9 +98,8 @@
u32 rq_bytes_sent; /* Bytes we have sent */
-#ifdef RPC_PROFILE
- unsigned long rq_xtime; /* when transmitted */
-#endif
+ long rq_xtime; /* when transmitted */
+ int rq_nresend;
};
#define rq_svec rq_snd_buf.head
#define rq_slen rq_snd_buf.len
diff -u --recursive --new-file linux-2.5.25/net/sunrpc/Makefile linux-2.5.25-rtt1/net/sunrpc/Makefile
--- linux-2.5.25/net/sunrpc/Makefile Sat May 25 01:33:46 2002
+++ linux-2.5.25-rtt1/net/sunrpc/Makefile Tue Jul 16 11:46:29 2002
@@ -9,7 +9,8 @@
sunrpc-y := clnt.o xprt.o sched.o \
auth.o auth_null.o auth_unix.o \
svc.o svcsock.o svcauth.o \
- pmap_clnt.o xdr.o sunrpc_syms.o
+ pmap_clnt.o timer.o xdr.o \
+ sunrpc_syms.o
sunrpc-$(CONFIG_PROC_FS) += stats.o
sunrpc-$(CONFIG_SYSCTL) += sysctl.o
sunrpc-objs := $(sunrpc-y)
diff -u --recursive --new-file linux-2.5.25/net/sunrpc/clnt.c linux-2.5.25-rtt1/net/sunrpc/clnt.c
--- linux-2.5.25/net/sunrpc/clnt.c Sun Jul 7 19:43:16 2002
+++ linux-2.5.25-rtt1/net/sunrpc/clnt.c Tue Jul 16 11:43:08 2002
@@ -104,6 +104,8 @@
if (!clnt->cl_port)
clnt->cl_autobind = 1;
+ rpc_init_rtt(&clnt->cl_rtt, xprt->timeout.to_initval);
+
if (!rpcauth_create(flavor, clnt))
goto out_no_auth;
diff -u --recursive --new-file linux-2.5.25/net/sunrpc/timer.c linux-2.5.25-rtt1/net/sunrpc/timer.c
--- linux-2.5.25/net/sunrpc/timer.c Thu Jan 1 01:00:00 1970
+++ linux-2.5.25-rtt1/net/sunrpc/timer.c Tue Jul 16 11:43:08 2002
@@ -0,0 +1,73 @@
+#include <linux/version.h>
+#include <linux/types.h>
+#include <linux/unistd.h>
+
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/xprt.h>
+#include <linux/sunrpc/timer.h>
+
+#define RPC_RTO_MAX (60*HZ)
+#define RPC_RTO_INIT (HZ/5)
+#define RPC_RTO_MIN (2)
+
+void
+rpc_init_rtt(struct rpc_rtt *rt, long timeo)
+{
+ long t = (timeo - RPC_RTO_INIT) << 3;
+ int i;
+ rt->timeo = timeo;
+ if (t < 0)
+ t = 0;
+ for (i = 0; i < 5; i++) {
+ rt->srtt[i] = t;
+ rt->sdrtt[i] = RPC_RTO_INIT;
+ }
+}
+
+void
+rpc_update_rtt(struct rpc_rtt *rt, int timer, long m)
+{
+ long *srtt, *sdrtt;
+
+ if (timer-- == 0)
+ return;
+
+ if (m == 0)
+ m = 1;
+ srtt = &rt->srtt[timer];
+ m -= *srtt >> 3;
+ *srtt += m;
+ if (m < 0)
+ m = -m;
+ sdrtt = &rt->sdrtt[timer];
+ m -= *sdrtt >> 2;
+ *sdrtt += m;
+ /* Set lower bound on the variance */
+ if (*sdrtt < RPC_RTO_MIN)
+ *sdrtt = RPC_RTO_MIN;
+}
+
+/*
+ * Estimate rto for an nfs rpc sent via. an unreliable datagram.
+ * Use the mean and mean deviation of rtt for the appropriate type of rpc
+ * for the frequent rpcs and a default for the others.
+ * The justification for doing "other" this way is that these rpcs
+ * happen so infrequently that timer est. would probably be stale.
+ * Also, since many of these rpcs are
+ * non-idempotent, a conservative timeout is desired.
+ * getattr, lookup,
+ * read, write, commit - A+4D
+ * other - timeo
+ */
+
+long
+rpc_calc_rto(struct rpc_rtt *rt, int timer)
+{
+ long res;
+ if (timer-- == 0)
+ return rt->timeo;
+ res = (rt->srtt[timer] >> 3) + rt->sdrtt[timer];
+ if (res > RPC_RTO_MAX)
+ res = RPC_RTO_MAX;
+ return res;
+}
diff -u --recursive --new-file linux-2.5.25/net/sunrpc/xprt.c linux-2.5.25-rtt1/net/sunrpc/xprt.c
--- linux-2.5.25/net/sunrpc/xprt.c Sun Jul 7 19:57:26 2002
+++ linux-2.5.25-rtt1/net/sunrpc/xprt.c Tue Jul 16 11:43:08 2002
@@ -480,13 +480,20 @@
* Complete reply received.
* The TCP code relies on us to remove the request from xprt->pending.
*/
-static inline void
+static void
xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
{
struct rpc_task *task = req->rq_task;
+ struct rpc_clnt *clnt = task->tk_client;
/* Adjust congestion window */
- xprt_adjust_cwnd(xprt, copied);
+ if (!xprt->nocong) {
+ xprt_adjust_cwnd(xprt, copied);
+ if (!req->rq_nresend) {
+ int timer = rpcproc_timer(clnt, task->tk_msg.rpc_proc);
+ if (timer)
+ rpc_update_rtt(&clnt->cl_rtt, timer, (long)jiffies - req->rq_xtime);
+ }
#ifdef RPC_PROFILE
/* Profile only reads for now */
@@ -934,6 +941,7 @@
spin_lock(&xprt->sock_lock);
if (req->rq_received)
goto out;
+ req->rq_nresend++;
xprt_adjust_cwnd(xprt, -ETIMEDOUT);
dprintk("RPC: %4d xprt_timer (%s request)\n",
@@ -982,15 +990,13 @@
if (!xprt_lock_write(xprt, task))
return;
-#ifdef RPC_PROFILE
- req->rq_xtime = jiffies;
-#endif
do_xprt_transmit(task);
}
static void
do_xprt_transmit(struct rpc_task *task)
{
+ struct rpc_clnt *clnt = task->tk_client;
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
int status, retry = 0;
@@ -1002,6 +1008,7 @@
*/
while (1) {
xprt_clear_wspace(xprt);
+ req->rq_xtime = jiffies;
status = xprt_sendmsg(xprt, req);
if (status < 0)
@@ -1065,7 +1072,21 @@
out_receive:
dprintk("RPC: %4d xmit complete\n", task->tk_pid);
/* Set the task's receive timeout value */
- task->tk_timeout = req->rq_timeout.to_current;
+ if (!xprt->nocong) {
+ int backoff;
+ task->tk_timeout = rpc_calc_rto(&clnt->cl_rtt,
+ rpcproc_timer(clnt, task->tk_msg.rpc_proc));
+ /* If we are retransmitting, increment the timeout counter */
+ backoff = req->rq_nresend;
+ if (backoff) {
+ if (backoff > 7)
+ backoff = 7;
+ task->tk_timeout <<= backoff;
+ }
+ if (task->tk_timeout > req->rq_timeout.to_maxval)
+ task->tk_timeout = req->rq_timeout.to_maxval;
+ } else
+ task->tk_timeout = req->rq_timeout.to_current;
spin_lock_bh(&xprt->sock_lock);
if (!req->rq_received)
rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
-
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This archive was generated by hypermail 2b29 : Tue Jul 23 2002 - 22:00:20 EST