1SMCSS(8) Linux Programmer's Manual SMCSS(8)
2
3
4
6 smcd-stats - Print statistics about SMC-D usage
7
8 smcr-stats - Print statistics about SMC-R usage
9
10
12 smcd [ OPTIONS ] stats { COMMAND | help }
13
14
15 smcr [ OPTIONS ] stats { COMMAND | help }
16
17
18
20 The smcd stats and smcr stats commands display statistics about SMC-D
21 and SMC-R, respectively. Data includes number of connections, number of
22 failed connections, buffer information, and special calls. Statistics
23 are collected at various data points in the smc kernel module. There‐
24 fore, minor inconsistencies in the data can occur and are to be ex‐
25 pected.
26
27
29 show (default)
30 Display statistics on respective SMC mode usage. Values dis‐
31 played are cumulative since last reset, unless option -a/--abso‐
32 lute is specified.
33
34
35 reset Display current statistics and reset all counters to zero.
36
37
38 json Display current statistics in JSON format.
39
40
42 -d, --details
43 Display additional fields and information in the output.
44
45
46 -a, --absolute
47 Display values since smc module load, ignoring any resets.
48
49
51 The -d/--details option displays a number of additional fields as indi‐
52 cated in the following. It also breaks up a number of counters in sec‐
53 tion Connections Summary into separate counts for client and server.
54
55
56 Total connections handled
57 Total number of connections handled by the SMC module. Includes TCP
58 fallback connections as well as handshake errors.
59
60
61 SMC connections
62 Number of connections that successfully entered the respective SMC
63 mode. -d/--details breaks up connections by SMC versions.
64
65
66 Handshake errors
67 Number of connections that failed due to errors during the handshaking
68 phase, e.g. peer no longer responding.
69
70
71 Avg requests per SMC conn
72 Average number of requests sent and received (including special socket
73 calls) per SMC connection.
74
75
76 TCP fallback
77 Number of connections that fell back to TCP/IP.
78
79
80 Data transmitted
81 Amount of data sent (TX) or received (RX) in Bytes.
82
83
84 Total requests
85 Total number of individual send (TX) or receive (RX) requests handled.
86 Includes requests that ended with errors or did not transfer any data.
87
88
89 Buffer full
90 Number of occurrences where the respective send buffer (TX) could not
91 contain all data to be sent, or did not contain as much data as re‐
92 quested in a receive call (RX).
93
94
95 Buffer full (remote) (--details only)
96 Number of occurrences where the peer's receive buffer was exceeded by
97 writing data. That is, requests that fill the buffer up to the last bit
98 are not included in the count.
99
100
101 Buffer too small (--details only)
102 Number of occurrences where a send request was larger than the local
103 send buffer's total capacity.
104
105
106 Buffer too small (remote) (--details only)
107 Number of occurrences where a send request exceeded the total capacity
108 of the peer's receive buffer.
109
110
111 Buffer downgrades (--details only)
112 Number of occurrences where a buffer of the requested size could not be
113 allocated for a new connection, and a smaller buffer was used.
114
115
116 Buffer reuses (--details only)
117 Number of occurrences where a buffer was provided as requested for a
118 new connection by reusing a buffer from a previous connection.
119
120
121 Bufs
122 Histogram of buffer sizes for all connections, including buffer down‐
123 grades and buffer reuses. The histogram scale presents exact buffer
124 sizes.
125
126
127 Reqs
128 Histogram of request sizes. The histogram scale includes upper bound‐
129 aries of request sizes. Counts reflect requested send sizes for TX, and
130 actual receive sizes for RX. Difference to Total requests is due to re‐
131 quests not transferring any data and/or erroneous requests.
132
133
134 Special socket calls
135 Summarizes the total number of sockets calls that require special han‐
136 dling in SMC. To categorize these calls into individual counters as
137 follows, use the -d/--details option.
138
139
140 cork Counts occurrences of sockopt TCP_CORK enablements. That is,
141 does not reflect the number of send requests with TCP_CORK en‐
142 abled.
143
144 nodelay
145 Counts occurrences of sockopt TCP_NODELAY enablements. That is,
146 does not reflect the number of send requests with TCP_CORK en‐
147 abled.
148
149 sendpage
150 Counts occurrences of the AF_SMC implementation of the sendpage
151 call.
152
153 splice Counts number of calls of the splice() system call.
154
155 urgent data
156 Counts number of send and receive calls with MSG_OOB set.
157
158
160 1. Show SMC-D statistics:
161 # smcd stats
162
163 2. Show detailed SMC-R statistics:
164 # smcr -d stats show
165
166 3. Show detailed SMC-R statistics and reset SMC-R statistics counters:
167 # smcr -d stats reset
168
169 4. Show detailed SMC-D statistics since module load in JSON format:
170 # smcd -da stats json
171
172
173
174 5. Show SMC-R statistics since module load:
175 # smcr -a stats
176
177
178
179
180
182 smcd(8), smcr(8)
183
184
185
186
187smc-tools June 2021 SMCSS(8)