NAME

       smcd-stats - Print statistics about SMC-D usage

       smcr-stats - Print statistics about SMC-R usage

SYNOPSIS

       smcd [ OPTIONS ] stats  { COMMAND | help }

       smcr [ OPTIONS ] stats  { COMMAND | help }

DESCRIPTION

       The smcd stats and smcr stats commands display statistics about SMC-D and SMC-R, respectively. Data
       includes number of connections, number of failed connections, buffer information, and special calls.
       Statistics are collected at various data points in the smc kernel module.  Therefore, minor
       inconsistencies in the data can occur and are to be expected.

COMMANDS

       show (default)
              Display statistics on respective SMC mode usage. Values displayed are cumulative since last reset,
              unless option -a/--absolute is specified.

       reset  Display current statistics and reset all counters to zero.

       json   Display current statistics in JSON format.

OPTIONS

       -d, --details
              Display additional fields and information in the output.

       -a, --absolute
              Display values since smc module load, ignoring any resets.

OUTPUT

       The  -d/--details  option  displays a number of additional fields as indicated in the following.  It also
       breaks up a number of counters in section Connections Summary into separate counts for client and server.

   Total connections handled
       Total number of connections handled by the SMC module. Includes  TCP  fallback  connections  as  well  as
       handshake errors.

   SMC connections
       Number  of  connections  that  successfully  entered  the  respective  SMC  mode.  -d/--details breaks up
       connections by SMC versions.

   Handshake errors
       Number of connections that failed due to errors  during  the  handshaking  phase,  e.g.  peer  no  longer
       responding.

   Avg requests per SMC conn
       Average number of requests sent and received (including special socket calls) per SMC connection.

   TCP fallback
       Number of connections that fell back to TCP/IP.

   Data transmitted
       Amount of data sent (TX) or received (RX) in Bytes.

   Total requests
       Total number of individual send (TX) or receive (RX) requests handled.  Includes requests that ended with
       errors or did not transfer any data.

   Buffer full
       Number of occurrences where the respective send buffer (TX) could not contain all data to be sent, or did
       not contain as much data as requested in a receive call (RX).

   Buffer full (remote) (--details only)
       Number  of  occurrences  where  the peer's receive buffer was exceeded by writing data. That is, requests
       that fill the buffer up to the last bit are not included in the count.

   Buffer too small (--details only)
       Number of occurrences where a send request was larger than the local send buffer's total capacity.

   Buffer too small (remote) (--details only)
       Number of occurrences where a send request exceeded the total capacity of the peer's receive buffer.

   Buffer downgrades (--details only)
       Number of occurrences where a buffer of the requested size could not be allocated for a  new  connection,
       and a smaller buffer was used.

   Buffer reuses (--details only)
       Number  of  occurrences where a buffer was provided as requested for a new connection by reusing a buffer
       from a previous connection.

   Bufs
       Histogram of buffer sizes for all connections,  including  buffer  downgrades  and  buffer  reuses.   The
       histogram scale presents exact buffer sizes.

   Reqs
       Histogram  of  request  sizes.  The  histogram  scale  includes upper boundaries of request sizes. Counts
       reflect requested send sizes for TX, and actual receive sizes for RX. Difference to Total requests is due
       to requests not transferring any data and/or erroneous requests.

   Special socket calls
       Summarizes the total number of sockets calls that require special handling in SMC.  To  categorize  these
       calls into individual counters as follows, use the -d/--details option.

       cork   Counts  occurrences  of sockopt TCP_CORK enablements. That is, does not reflect the number of send
              requests with TCP_CORK enabled.

       nodelay
              Counts occurrences of sockopt TCP_NODELAY enablements. That is, does not  reflect  the  number  of
              send requests with TCP_CORK enabled.

       sendpage
              Counts occurrences of the AF_SMC implementation of the sendpage call.

       splice Counts number of calls of the splice() system call.

       urgent data
              Counts number of send and receive calls with MSG_OOB set.

EXAMPLES

       1. Show SMC-D statistics:
         # smcd stats

       2. Show detailed SMC-R statistics:
         # smcr -d stats show

       3. Show detailed SMC-R statistics and reset SMC-R statistics counters:
         # smcr -d stats reset

       4. Show detailed SMC-D statistics since module load in JSON format:
         # smcd -da stats json

       5. Show SMC-R statistics since module load:
         # smcr -a stats

SEE ALSO

       smcd(8), smcr(8)

smc-tools                                           June 2021                                      SMCD-STATS(8)