smcr-stats(8)

1SMCSS(8)                   Linux Programmer's Manual                  SMCSS(8)
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NAME

6       smcd-stats - Print statistics about SMC-D usage
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8       smcr-stats - Print statistics about SMC-R usage
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SYNOPSIS

12       smcd [ OPTIONS ] stats  { COMMAND | help }
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15       smcr [ OPTIONS ] stats  { COMMAND | help }
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DESCRIPTION

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.
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COMMANDS

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.
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35       reset  Display current statistics and reset all counters to zero.
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38       json   Display current statistics in JSON format.
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OPTIONS

42       -d, --details
43              Display additional fields and information in the output.
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46       -a, --absolute
47              Display values since smc module load, ignoring any resets.
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OUTPUT

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.
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56   Total connections handled
57       Total number of connections handled by the SMC module. Includes TCP
58       fallback connections as well as handshake errors.
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61   SMC connections
62       Number of connections that successfully entered the respective SMC
63       mode.  -d/--details breaks up connections by SMC versions.
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66   Handshake errors
67       Number of connections that failed due to errors during the handshaking
68       phase, e.g. peer no longer responding.
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71   Avg requests per SMC conn
72       Average number of requests sent and received (including special socket
73       calls) per SMC connection.
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76   TCP fallback
77       Number of connections that fell back to TCP/IP.
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80   Data transmitted
81       Amount of data sent (TX) or received (RX) in Bytes.
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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.
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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).
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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149       sendpage
150              Counts occurrences of the AF_SMC implementation of the sendpage
151              call.
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153       splice Counts number of calls of the splice() system call.
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155       urgent data
156              Counts number of send and receive calls with MSG_OOB set.
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EXAMPLES

160       1. Show SMC-D statistics:
161         # smcd stats
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163       2. Show detailed SMC-R statistics:
164         # smcr -d stats show
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166       3. Show detailed SMC-R statistics and reset SMC-R statistics counters:
167         # smcr -d stats reset
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169       4. Show detailed SMC-D statistics since module load in JSON format:
170         # smcd -da stats json
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174       5. Show SMC-R statistics since module load:
175         # smcr -a stats
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