NFS: introduce mechanism for tracking NFS client metrics
Add a per-superblock performance counter facility to the NFS client. This
facility mimics the counters available for block devices and for
networking. Expose these new counters via the new /proc/self/mountstats
interface.
Thanks to Andrew Morton and Trond Myklebust for their review and comments.
Test plan:
fsx and iozone on UP and SMP systems, with and without pre-emption. Watch
for memory overwrite bugs, and performance loss (significantly more CPU
required per op).
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 827d692..86b756f 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -42,6 +42,7 @@
#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
+#include "iostat.h"
#define NFSDBG_FACILITY NFSDBG_VFS
#define NFS_PARANOIA 1
@@ -65,6 +66,7 @@
static void nfs_umount_begin(struct super_block *);
static int nfs_statfs(struct super_block *, struct kstatfs *);
static int nfs_show_options(struct seq_file *, struct vfsmount *);
+static int nfs_show_stats(struct seq_file *, struct vfsmount *);
static void nfs_zap_acl_cache(struct inode *);
static struct rpc_program nfs_program;
@@ -78,6 +80,7 @@
.clear_inode = nfs_clear_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
+ .show_stats = nfs_show_stats,
};
/*
@@ -290,6 +293,12 @@
}
sb->s_root->d_op = server->rpc_ops->dentry_ops;
+ server->io_stats = nfs_alloc_iostats();
+ if (!server->io_stats) {
+ no_root_error = -ENOMEM;
+ goto out_no_root;
+ }
+
/* Get some general file system info */
if (server->namelen == 0 &&
server->rpc_ops->pathconf(server, &server->fh, &pathinfo) >= 0)
@@ -582,7 +591,7 @@
}
-static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
+static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
{
static struct proc_nfs_info {
int flag;
@@ -598,20 +607,19 @@
{ 0, NULL, NULL }
};
struct proc_nfs_info *nfs_infop;
- struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
char buf[12];
char *proto;
seq_printf(m, ",vers=%d", nfss->rpc_ops->version);
seq_printf(m, ",rsize=%d", nfss->rsize);
seq_printf(m, ",wsize=%d", nfss->wsize);
- if (nfss->acregmin != 3*HZ)
+ if (nfss->acregmin != 3*HZ || showdefaults)
seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
- if (nfss->acregmax != 60*HZ)
+ if (nfss->acregmax != 60*HZ || showdefaults)
seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
- if (nfss->acdirmin != 30*HZ)
+ if (nfss->acdirmin != 30*HZ || showdefaults)
seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
- if (nfss->acdirmax != 60*HZ)
+ if (nfss->acdirmax != 60*HZ || showdefaults)
seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
if (nfss->flags & nfs_infop->flag)
@@ -633,8 +641,89 @@
seq_printf(m, ",proto=%s", proto);
seq_printf(m, ",timeo=%lu", 10U * nfss->retrans_timeo / HZ);
seq_printf(m, ",retrans=%u", nfss->retrans_count);
+}
+
+static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+ struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
+
+ nfs_show_mount_options(m, nfss, 0);
+
seq_puts(m, ",addr=");
seq_escape(m, nfss->hostname, " \t\n\\");
+
+ return 0;
+}
+
+static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
+{
+ int i, cpu;
+ struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
+ struct rpc_auth *auth = nfss->client->cl_auth;
+ struct nfs_iostats totals = { };
+
+ seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
+
+ /*
+ * Display all mount option settings
+ */
+ seq_printf(m, "\n\topts:\t");
+ seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
+ seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
+ seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
+ seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
+ nfs_show_mount_options(m, nfss, 1);
+
+ seq_printf(m, "\n\tcaps:\t");
+ seq_printf(m, "caps=0x%x", nfss->caps);
+ seq_printf(m, ",wtmult=%d", nfss->wtmult);
+ seq_printf(m, ",dtsize=%d", nfss->dtsize);
+ seq_printf(m, ",bsize=%d", nfss->bsize);
+ seq_printf(m, ",namelen=%d", nfss->namelen);
+
+#ifdef CONFIG_NFS_V4
+ if (nfss->rpc_ops->version == 4) {
+ seq_printf(m, "\n\tnfsv4:\t");
+ seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
+ seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
+ seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
+ }
+#endif
+
+ /*
+ * Display security flavor in effect for this mount
+ */
+ seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
+ if (auth->au_flavor)
+ seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
+
+ /*
+ * Display superblock I/O counters
+ */
+ for (cpu = 0; cpu < NR_CPUS; cpu++) {
+ struct nfs_iostats *stats;
+
+ if (!cpu_possible(cpu))
+ continue;
+
+ preempt_disable();
+ stats = per_cpu_ptr(nfss->io_stats, cpu);
+
+ for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
+ totals.events[i] += stats->events[i];
+ for (i = 0; i < __NFSIOS_BYTESMAX; i++)
+ totals.bytes[i] += stats->bytes[i];
+
+ preempt_enable();
+ }
+
+ seq_printf(m, "\n\tevents:\t");
+ for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
+ seq_printf(m, "%lu ", totals.events[i]);
+ seq_printf(m, "\n\tbytes:\t");
+ for (i = 0; i < __NFSIOS_BYTESMAX; i++)
+ seq_printf(m, "%Lu ", totals.bytes[i]);
+
return 0;
}
@@ -1742,6 +1831,7 @@
.clear_inode = nfs4_clear_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
+ .show_stats = nfs_show_stats,
};
/*
@@ -2015,6 +2105,7 @@
out_free:
kfree(server->mnt_path);
kfree(server->hostname);
+ nfs_free_iostats(server->io_stats);
kfree(server);
return s;
}
diff --git a/fs/nfs/iostat.h b/fs/nfs/iostat.h
new file mode 100644
index 0000000..dc080e5
--- /dev/null
+++ b/fs/nfs/iostat.h
@@ -0,0 +1,152 @@
+/*
+ * linux/fs/nfs/iostat.h
+ *
+ * Declarations for NFS client per-mount statistics
+ *
+ * Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
+ *
+ * NFS client per-mount statistics provide information about the health of
+ * the NFS client and the health of each NFS mount point. Generally these
+ * are not for detailed problem diagnosis, but simply to indicate that there
+ * is a problem.
+ *
+ * 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.
+ */
+
+#ifndef _NFS_IOSTAT
+#define _NFS_IOSTAT
+
+#define NFS_IOSTAT_VERS "1.0"
+
+/*
+ * NFS byte counters
+ *
+ * 1. SERVER - the number of payload bytes read from or written to the
+ * server by the NFS client via an NFS READ or WRITE request.
+ *
+ * 2. NORMAL - the number of bytes read or written by applications via
+ * the read(2) and write(2) system call interfaces.
+ *
+ * 3. DIRECT - the number of bytes read or written from files opened
+ * with the O_DIRECT flag.
+ *
+ * These counters give a view of the data throughput into and out of the NFS
+ * client. Comparing the number of bytes requested by an application with the
+ * number of bytes the client requests from the server can provide an
+ * indication of client efficiency (per-op, cache hits, etc).
+ *
+ * These counters can also help characterize which access methods are in
+ * use. DIRECT by itself shows whether there is any O_DIRECT traffic.
+ * NORMAL + DIRECT shows how much data is going through the system call
+ * interface. A large amount of SERVER traffic without much NORMAL or
+ * DIRECT traffic shows that applications are using mapped files.
+ *
+ * NFS page counters
+ *
+ * These count the number of pages read or written via nfs_readpage(),
+ * nfs_readpages(), or their write equivalents.
+ */
+enum nfs_stat_bytecounters {
+ NFSIOS_NORMALREADBYTES = 0,
+ NFSIOS_NORMALWRITTENBYTES,
+ NFSIOS_DIRECTREADBYTES,
+ NFSIOS_DIRECTWRITTENBYTES,
+ NFSIOS_SERVERREADBYTES,
+ NFSIOS_SERVERWRITTENBYTES,
+ NFSIOS_READPAGES,
+ NFSIOS_WRITEPAGES,
+ __NFSIOS_BYTESMAX,
+};
+
+/*
+ * NFS event counters
+ *
+ * These counters provide a low-overhead way of monitoring client activity
+ * without enabling NFS trace debugging. The counters show the rate at
+ * which VFS requests are made, and how often the client invalidates its
+ * data and attribute caches. This allows system administrators to monitor
+ * such things as how close-to-open is working, and answer questions such
+ * as "why are there so many GETATTR requests on the wire?"
+ *
+ * They also count anamolous events such as short reads and writes, silly
+ * renames due to close-after-delete, and operations that change the size
+ * of a file (such operations can often be the source of data corruption
+ * if applications aren't using file locking properly).
+ */
+enum nfs_stat_eventcounters {
+ NFSIOS_INODEREVALIDATE = 0,
+ NFSIOS_DENTRYREVALIDATE,
+ NFSIOS_DATAINVALIDATE,
+ NFSIOS_ATTRINVALIDATE,
+ NFSIOS_VFSOPEN,
+ NFSIOS_VFSLOOKUP,
+ NFSIOS_VFSACCESS,
+ NFSIOS_VFSUPDATEPAGE,
+ NFSIOS_VFSREADPAGE,
+ NFSIOS_VFSREADPAGES,
+ NFSIOS_VFSWRITEPAGE,
+ NFSIOS_VFSWRITEPAGES,
+ NFSIOS_VFSGETDENTS,
+ NFSIOS_VFSSETATTR,
+ NFSIOS_VFSFLUSH,
+ NFSIOS_VFSFSYNC,
+ NFSIOS_VFSLOCK,
+ NFSIOS_VFSRELEASE,
+ NFSIOS_CONGESTIONWAIT,
+ NFSIOS_SETATTRTRUNC,
+ NFSIOS_EXTENDWRITE,
+ NFSIOS_SILLYRENAME,
+ NFSIOS_SHORTREAD,
+ NFSIOS_SHORTWRITE,
+ __NFSIOS_COUNTSMAX,
+};
+
+#ifdef __KERNEL__
+
+#include <linux/percpu.h>
+#include <linux/cache.h>
+
+struct nfs_iostats {
+ unsigned long long bytes[__NFSIOS_BYTESMAX];
+ unsigned long events[__NFSIOS_COUNTSMAX];
+} ____cacheline_aligned;
+
+static inline void nfs_inc_stats(struct inode *inode, enum nfs_stat_eventcounters stat)
+{
+ struct nfs_iostats *iostats;
+ int cpu;
+
+ cpu = get_cpu();
+ iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
+ iostats->events[stat] ++;
+ put_cpu_no_resched();
+}
+
+static inline void nfs_add_stats(struct inode *inode, enum nfs_stat_bytecounters stat, unsigned long addend)
+{
+ struct nfs_iostats *iostats;
+ int cpu;
+
+ cpu = get_cpu();
+ iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
+ iostats->bytes[stat] += addend;
+ put_cpu_no_resched();
+}
+
+static inline struct nfs_iostats *nfs_alloc_iostats(void)
+{
+ return alloc_percpu(struct nfs_iostats);
+}
+
+static inline void nfs_free_iostats(struct nfs_iostats *stats)
+{
+ free_percpu(stats);
+}
+
+#endif
+#endif
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index a522ab9..d65e69a 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -4,6 +4,8 @@
#include <linux/list.h>
#include <linux/backing-dev.h>
+struct nfs_iostats;
+
/*
* NFS client parameters stored in the superblock.
*/
@@ -12,6 +14,7 @@
struct rpc_clnt * client_sys; /* 2nd handle for FSINFO */
struct rpc_clnt * client_acl; /* ACL RPC client handle */
struct nfs_rpc_ops * rpc_ops; /* NFS protocol vector */
+ struct nfs_iostats * io_stats; /* I/O statistics */
struct backing_dev_info backing_dev_info;
int flags; /* various flags */
unsigned int caps; /* server capabilities */