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authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-27 13:14:39 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-27 13:14:39 -0400
commitd2c3ac7e7e39ec6d37e4114ae7444948561e59af (patch)
treec0e6a9eed0139de4e757fbf64498fe8c0b291e44 /Documentation/filesystems
parent546fac60739ef8d7cbf8ce0b8251a519f68b2804 (diff)
parent901f1379f6c9dc2d73b51971d129a6f7d5b9b20a (diff)
Merge branch 'for-4.2' of git://linux-nfs.org/~bfields/linux
Pull nfsd updates from Bruce Fields: "A relatively quiet cycle, with a mix of cleanup and smaller bugfixes" * 'for-4.2' of git://linux-nfs.org/~bfields/linux: (24 commits) sunrpc: use sg_init_one() in krb5_rc4_setup_enc/seq_key() nfsd: wrap too long lines in nfsd4_encode_read nfsd: fput rd_file from XDR encode context nfsd: take struct file setup fully into nfs4_preprocess_stateid_op nfsd: refactor nfs4_preprocess_stateid_op nfsd: clean up raparams handling nfsd: use swap() in sort_pacl_range() rpcrdma: Merge svcrdma and xprtrdma modules into one svcrdma: Add a separate "max data segs macro for svcrdma svcrdma: Replace GFP_KERNEL in a loop with GFP_NOFAIL svcrdma: Keep rpcrdma_msg fields in network byte-order svcrdma: Fix byte-swapping in svc_rdma_sendto.c nfsd: Update callback sequnce id only CB_SEQUENCE success nfsd: Reset cb_status in nfsd4_cb_prepare() at retrying svcrdma: Remove svc_rdma_xdr_decode_deferred_req() SUNRPC: Move EXPORT_SYMBOL for svc_process uapi/nfs: Add NFSv4.1 ACL definitions nfsd: Remove dead declarations nfsd: work around a gcc-5.1 warning nfsd: Checking for acl support does not require fetching any acls ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/nfs/knfsd-stats.txt44
1 files changed, 4 insertions, 40 deletions
diff --git a/Documentation/filesystems/nfs/knfsd-stats.txt b/Documentation/filesystems/nfs/knfsd-stats.txt
index 64ced5149d37..1a5d82180b84 100644
--- a/Documentation/filesystems/nfs/knfsd-stats.txt
+++ b/Documentation/filesystems/nfs/knfsd-stats.txt
@@ -68,16 +68,10 @@ sockets-enqueued
68 rate of change for this counter is zero; significantly non-zero 68 rate of change for this counter is zero; significantly non-zero
69 values may indicate a performance limitation. 69 values may indicate a performance limitation.
70 70
71 This can happen either because there are too few nfsd threads in the 71 This can happen because there are too few nfsd threads in the thread
72 thread pool for the NFS workload (the workload is thread-limited), 72 pool for the NFS workload (the workload is thread-limited), in which
73 or because the NFS workload needs more CPU time than is available in 73 case configuring more nfsd threads will probably improve the
74 the thread pool (the workload is CPU-limited). In the former case, 74 performance of the NFS workload.
75 configuring more nfsd threads will probably improve the performance
76 of the NFS workload. In the latter case, the sunrpc server layer is
77 already choosing not to wake idle nfsd threads because there are too
78 many nfsd threads which want to run but cannot, so configuring more
79 nfsd threads will make no difference whatsoever. The overloads-avoided
80 statistic (see below) can be used to distinguish these cases.
81 75
82threads-woken 76threads-woken
83 Counts how many times an idle nfsd thread is woken to try to 77 Counts how many times an idle nfsd thread is woken to try to
@@ -88,36 +82,6 @@ threads-woken
88 thing. The ideal rate of change for this counter will be close 82 thing. The ideal rate of change for this counter will be close
89 to but less than the rate of change of the packets-arrived counter. 83 to but less than the rate of change of the packets-arrived counter.
90 84
91overloads-avoided
92 Counts how many times the sunrpc server layer chose not to wake an
93 nfsd thread, despite the presence of idle nfsd threads, because
94 too many nfsd threads had been recently woken but could not get
95 enough CPU time to actually run.
96
97 This statistic counts a circumstance where the sunrpc layer
98 heuristically avoids overloading the CPU scheduler with too many
99 runnable nfsd threads. The ideal rate of change for this counter
100 is zero. Significant non-zero values indicate that the workload
101 is CPU limited. Usually this is associated with heavy CPU usage
102 on all the CPUs in the nfsd thread pool.
103
104 If a sustained large overloads-avoided rate is detected on a pool,
105 the top(1) utility should be used to check for the following
106 pattern of CPU usage on all the CPUs associated with the given
107 nfsd thread pool.
108
109 - %us ~= 0 (as you're *NOT* running applications on your NFS server)
110
111 - %wa ~= 0
112
113 - %id ~= 0
114
115 - %sy + %hi + %si ~= 100
116
117 If this pattern is seen, configuring more nfsd threads will *not*
118 improve the performance of the workload. If this patten is not
119 seen, then something more subtle is wrong.
120
121threads-timedout 85threads-timedout
122 Counts how many times an nfsd thread triggered an idle timeout, 86 Counts how many times an nfsd thread triggered an idle timeout,
123 i.e. was not woken to handle any incoming network packets for 87 i.e. was not woken to handle any incoming network packets for