xref: /linux/Documentation/ABI/testing/procfs-nfsd-reply_cache_stats (revision d141ec2825b4d3ec52f27c43bdd864090159273a)
1*284a474eSChuck LeverWhat:		/proc/fs/nfsd/reply_cache_stats
2*284a474eSChuck LeverDate:		March 2013
3*284a474eSChuck LeverKernelVersion:	3.10
4*284a474eSChuck LeverContact:	linux-nfs@vger.kernel.org
5*284a474eSChuck LeverDescription:
6*284a474eSChuck Lever		Provides statistics for the NFS server duplicate reply
7*284a474eSChuck Lever		cache (DRC). The file contains one labeled field per
8*284a474eSChuck Lever		line. Each line has the form "field name:" followed by
9*284a474eSChuck Lever		whitespace and a decimal value.
10*284a474eSChuck Lever
11*284a474eSChuck Lever		Fields:
12*284a474eSChuck Lever
13*284a474eSChuck Lever		=======================  ======  ==========================
14*284a474eSChuck Lever		max entries              u32     Upper bound on cache size
15*284a474eSChuck Lever		num entries              u32     Current entry count
16*284a474eSChuck Lever		hash buckets             u32     Number of hash buckets
17*284a474eSChuck Lever		mem usage                s64     Bytes consumed by the DRC
18*284a474eSChuck Lever		cache hits               s64     Requests answered from cache
19*284a474eSChuck Lever		cache misses             s64     Requests not found in cache
20*284a474eSChuck Lever		not cached               s64     Idempotent requests that
21*284a474eSChuck Lever		                                 bypass the cache
22*284a474eSChuck Lever		payload misses           s64     XID matched but request
23*284a474eSChuck Lever		                                 checksum did not
24*284a474eSChuck Lever		longest chain len        u32     Longest hash chain observed
25*284a474eSChuck Lever		cachesize at longest     u32     Cache size when longest
26*284a474eSChuck Lever		                                 chain was recorded
27*284a474eSChuck Lever		=======================  ======  ==========================
28*284a474eSChuck Lever
29*284a474eSChuck Lever		Counter fields (cache hits, cache misses, not cached,
30*284a474eSChuck Lever		payload misses, mem usage) are maintained with per-cpu
31*284a474eSChuck Lever		counters and may briefly show stale values under
32*284a474eSChuck Lever		concurrent load. There is no way to reset these
33*284a474eSChuck Lever		counters; consumers should compute rates by sampling
34*284a474eSChuck Lever		over time.
35*284a474eSChuck Lever
36*284a474eSChuck Lever		New fields may be appended in future kernels. Parsers
37*284a474eSChuck Lever		should match on field name, not line position.
38*284a474eSChuck LeverUsers:		nfs-utils (https://git.linux-nfs.org/?p=steved/nfs-utils.git)
39