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Updated: Wednesday, February 10, 2021
 
 

memaslap (1)

Name

memaslap - libmemcached Documentation

Synopsis

memaslap [options]

--help

MEMCACHED_SERVERS

Description

MEMASLAP(1)                      libmemcached                      MEMASLAP(1)



NAME
       memaslap - libmemcached Documentation

SYNOPSIS
       memaslap [options]

       --help

       MEMCACHED_SERVERS

DESCRIPTION
       memaslap is a load generation and benchmark tool for memcached servers.
       It generates configurable workload such as threads, concurrencies, con-
       nections, run time, overwrite, miss rate, key size, value size, get/set
       proportion, expected throughput, and so on. Furthermore, it also testss
       data  verification,  expire-time  verification,  UDP,  binary protocol,
       facebook test, replication test, multi-get and reconnection, etc.

       Memaslap manages network connections like memcached with libevent. Each
       thread of memaslap is bound with a CPU core, all the threads don't com-
       municate with each other, and there are several socket  connections  in
       each  thread.  Each  connection keeps key size distribution, value size
       distribution, and command distribution by itself.

       You can specify servers via the memslap --servers  option  or  via  the
       environment variable MEMCACHED_SERVERS.

FEATURES
       Memslap is developed to for the following purposes:

       Manages network connections with libevent asynchronously.

       Set both TCP and UDP up to use non-blocking IO.

       Improves parallelism: higher performance in multi-threads environments.

       Improves time efficiency: faster processing speed.

       Generates  key  and  value  more efficiently; key size distribution and
       value size distribution are configurable.

       Supports get, multi-get, and set commands; command distribution is con-
       figurable.

       Supports controllable miss rate and overwrite rate.

       Supports data and expire-time verification.

       Supports dumping statistic information periodically.

       Supports thousands of TCP connections.

       Supports binary protocol.

       Supports facebook test (set with TCP and multi-get with UDP) and repli-
       cation test.

DETAILS
   Effective implementation of network.
       For memaslap, both TCP and UDP use non-blocking  network  IO.  All  the
       network events are managed by libevent as memcached. The network module
       of memaslap is similar to memcached. Libevent can ensure  memaslap  can
       handle network very efficiently.

   Effective implementation of multi-threads and concurrency
       Memslap  has  the similar implementation of multi-threads to memcached.
       Memslap creates one or more self-governed threads; each thread is bound
       with one CPU core if the system testss setting CPU core affinity.

       In  addition,  each  thread  has a libevent to manage the events of the
       network; each thread has one or more self-governed  concurrencies;  and
       each concurrency has one or more socket connections. All the concurren-
       cies dont communicate with each other even though they are in the  same
       thread.

       Memslap  can  create  thousands of socket connections, and each concur-
       rency has tens of socket  connections.  Each  concurrency  randomly  or
       sequentially  selects  one socket connection from its socket connection
       pool to run, so memaslap can ensure each concurrency handles one socket
       connection  at  any given time. Users can specify the number of concur-
       rency and socket connections of each  concurrency  according  to  their
       expected workload.

   Effective implementation of generating key and value
       In order to improve time efficiency and space efficiency, memaslap cre-
       ates a random characters table with 10M characters. All the suffixes of
       keys and values are generated from this random characters table.

       Memslap  uses  the  offset in the character table and the length of the
       string to identify a string. It can save much memory.   Each  key  con-
       tains  two  parts,  a prefix and a suffix. The prefix is an uint64_t, 8
       bytes. In order to verify the data set before, memaslap need to  ensure
       each key is unique, so it uses the prefix to identify a key. The prefix
       cannot include illegal characters, such as r, n, 0 and  . And  memaslap
       has an algorithm to ensure that.

       Memslap doesnt generate all the objects (key-value pairs) at the begin-
       ning. It only generates enough objects to fill the task window (default
       10K  objects)  of each concurrency. Each object has the following basic
       information, key prefix, key suffix offset in the character table,  key
       length, value offset in the character table, and value length.

       In  the work process, each concurrency sequentially or randomly selects
       an object from the window to do set operation or get operation. At  the
       same  time,  each  concurrency kicks objects out of its window and adds
       new object into it.

   Simple but useful task scheduling
       Memslap uses libevent to schedule all the concurrencies of threads, and
       each  concurrency  schedules tasks based on the local task window. Mem-
       slap assumes that if each concurrency keeps the same key  distribution,
       value  distribution  and  commands distribution, from outside, memaslap
       keeps all the distribution as a whole.  Each task window includes a lot
       of  objects,  each  object  stores  its basic information, such as key,
       value, expire time, and so on. At any time, all the objects in the win-
       dow keep the same and fixed key and value distribution. If an object is
       overwritten, the value of the object will be updated. Memslap  verifies
       the  data  or expire-time according to the object information stored in
       the task window.

       Libevent selects which concurrency to handle based on a  specific  net-
       work  event. Then the concurrency selects which command (get or set) to
       operate based on the command distribution. If it needs to kick  out  an
       old  object  and  add  a  new object, in order to keep the same key and
       value distribution, the new object must have the same  key  length  and
       value length.

       If  memcached  server  has  two  cache layers (memory and SSD), running
       memaslap with different window  sizes  can  get  different  cache  miss
       rates.  If  memaslap adds enough objects into the windows at the begin-
       ning, and the cache of memcached cannot store all the objects  initial-
       ized,  then memaslap will get some objects from the second cache layer.
       It causes the first cache layer to miss. So the user  can  specify  the
       window size to get the expected miss rate of the first cache layer.

   Useful  implementation  of  multi-servers  , UDP, TCP, multi-get and binary
       protocol
       Because each thread is self-governed,  memaslap  can  assign  different
       threads  to handle different memcached servers. This is just one of the
       ways in which memaslap tests multiple servers. The only  limitation  is
       that  the  number  of  servers  cannot  be  greater  than the number of
       threads. The other way to test  multiple  servers  is  for  replication
       test.  Each  concurrency  has  one  socket connection to each memcached
       server.  For the implementation, memaslap can set some objects  to  one
       memcached server, and get these objects from the other servers.

       By  default,  Memslap  does single get. If the user specifies multi-get
       option, memaslap will collect enough get commands and pack and send the
       commands together.

       Memslap testss both the ASCII protocol and binary protocol, but it runs
       on the ASCII protocol by default.  Memslap by default runs on  the  TCP
       protocol,  but  it  also  tests UDP. Because UDP is unreliable, dropped
       packages and out-of-order packages may occur. Memslap creates a  memory
       buffer to handle these problems. Memslap tries to read all the response
       data of one command from the server and reorders the response data.  If
       some  packages  get  lost,  the  waiting  timeout  mechanism can ensure
       half-baked packages will be discarded and  the  next  command  will  be
       sent.

USAGE
       Below are some usage samples:

       memaslap -s 127.0.0.1:11211 -S 5s

       memaslap -s 127.0.0.1:11211 -t 2m -v 0.2 -e 0.05 -b

       memaslap -s 127.0.0.1:11211 -F config -t 2m -w 40k -S 20s -o 0.2

       memaslap -s 127.0.0.1:11211 -F config -t 2m -T 4 -c 128 -d 20 -P 40k

       memaslap -s 127.0.0.1:11211 -F config -t 2m -d 50 -a -n 40

       memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m

       memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m -p 2

       The  user must specify one server at least to run memaslap. The rest of
       the parameters have default values, as shown below:

       Thread number = 1                    Concurrency = 16

       Run time = 600 seconds                Configuration file = NULL

       Key size = 64                         Value size = 1024

       Get/set = 9:1                         Window size = 10k

       Execute number = 0                   Single get = true

       Multi-get = false                      Number of sockets of  each  con-
       currency = 1

       Reconnect = false                     Data verification = false

       Expire-time verification = false           ASCII protocol = true

       Binary protocol = false                 Dumping statistic information

       periodically = false

       Overwrite proportion = 0%             UDP = false

       TCP = true                           Limit throughput = false

       Facebook test = false                  Replication test = false

   Key size, value size and command distribution.
       All the distributions are read from the configuration file specified by
       user with cfg_cmd option. If the user does not specify a  configuration
       file,  memaslap  will run with the default distribution (key size = 64,
       value size = 1024, get/set = 9:1). For information on how to  edit  the
       configuration file, refer to the Configuration File section.

       The  minimum  key  size is 16 bytes; the maximum key size is 250 bytes.
       The precision of proportion is 0.001. The  proportion  of  distribution
       will be rounded to 3 decimal places.

       The  minimum value size is 1 bytes; the maximum value size is 1M bytes.
       The precision of proportion is 0.001. The  proportion  of  distribution
       will  be  rounded to 3 decimal places.  Currently, memaslap only testss
       set and get commands. And it testss 100% set and  100%  get.  For  100%
       get, it will preset some objects to the server.

   Multi-thread and concurrency
       The  high performance of memaslap benefits from the special schedule of
       thread and concurrency. Its important to specify the proper  number  of
       them. The default number of threads is 1; the default number of concur-
       rency is 16. The user can use  threads  and  --concurrency  to  specify
       these variables.

       If  the  system  tests  setting  CPU affinity and the number of threads
       specified by the user is greater than 1, memaslap will try to bind each
       thread  to a different CPU core. So if you want to get the best perfor-
       mance memaslap, it is better to specify the number of thread  equal  to
       the  number  of  CPU cores. The number of threads specified by the user
       can also be less or greater than the number of CPU  cores.  Because  of
       the  limitation of implementation, the number of concurrencies could be
       the multiple of the number of threads.

       1. For 8 CPU cores system

       For example:

       --threads=2 --concurrency=128

       --threads=8 --concurrency=128

       --threads=8 --concurrency=256

       --threads=12 --concurrency=144

       2. For 16 CPU cores system

       For example:

       --threads=8 --concurrency=128

       --threads=16 --concurrency=256

       --threads=16 --concurrency=512

       --threads=24 --concurrency=288

       The memaslap performs very well, when used to test the  performance  of
       memcached  servers.  Most of the time, the bottleneck is the network or
       the server. If for some reason the user wants to limit the  performance
       of memaslap, there are two ways to do this:

       Decrease the number of threads and concurrencies.  Use the option --tps
       that memaslap provides to limit the throughput. This option allows  the
       user to get the expected throughput. For example, assume that the maxi-
       mum throughput is 50 kops/s for a specific configuration, you can spec-
       ify  the  throughput equal to or less than the maximum throughput using
       --tps option.

   Window size
       Most of the time, the user does not need to specify  the  window  size.
       The  default  window  size is 10k. For Schooner Memcached, the user can
       specify different window sizes to get different cache miss rates  based
       on  the  test case. Memslap testss cache miss rate between 0% and 100%.
       If you use this utility to test the performance of Schooner  Memcached,
       you  can  specify  a  proper window size to get the expected cache miss
       rate. The formula for calculating window size is as follows:

       Assume that the key size is 128 bytes,  and  the  value  size  is  2048
       bytes, and concurrency=128.

       1.  Small cache cache_size=1M, 100% cache miss (all data get from SSD).
       win_size=10k

       2. cache_size=4G

       (1). cache miss rate 0%

       win_size=8k

       (2). cache miss rate 5%

       win_size=11k

       3. cache_size=16G

       (1). cache miss rate 0%

       win_size=32k

       (2). cache miss

       rate 5%

       win_size=46k

       The formula for calculating window size for cache miss rate 0%:

       cache_size / concurrency / (key_size + value_size) * 0.5

       The formula for calculating window size for cache miss rate 5%:

       cache_size / concurrency / (key_size + value_size) * 0.7

   Verification
       Memslap testss both data verification and expire-time verification. The
       user can use "--verify=" or "-v" to specify the proportion of data ver-
       ification. In theory, it testss 100% data verification.  The  user  can
       use  "--exp_verify="  or  "-e" to specify the proportion of expire-time
       verification. In theory, it testss 100% expire-time verification. Spec-
       ify the "--verbose" options to get more detailed error information.

       For  example:  --exp_verify=0.01  verify=0.1  , it means that 1% of the
       objects set with expire-time, 10% of the objects gotten will  be  veri-
       fied.  If  the objects are gotten, memaslap will verify the expire-time
       and value.

   multi-servers and multi-config
       Memslap testss multi-servers based on self-governed thread.  There is a
       limitation that the number of servers cannot be greater than the number
       of threads. Memslap assigns one thread to handle one server  at  least.
       The   user   can  use  the  "--servers="  or  "-s"  option  to  specify
       multi-servers.

       For example:

       --servers=10.1.1.1:11211,10.1.1.2:11212,10.1.1.3:11213      --threads=6
       --concurrency=36

       The above command means that there are 6 threads, with each thread hav-
       ing  6  concurrencies  and  that  threads  0  and  3  handle  server  0
       (10.1.1.1);  threads  1  and 4 handle server 1 (10.1.1.2); and thread 2
       and 5 handle server 2 (10.1.1.3).

       All the threads and concurrencies in memaslap are self-governed.

       So is memaslap. The user can start up several memaslap  instances.  The
       user  can run memaslap on different client machines to communicate with
       the same memcached server at the same. It is recommended that the  user
       start  different memaslap on different machines using the same configu-
       ration.

   Run with execute number mode or time mode
       The default memaslap runs with time mode. The default run  time  is  10
       minutes.  If it times out, memaslap will exit. Do not specify both exe-
       cute number mode and time mode at  the  same  time;  just  specify  one
       instead.

       For example:

       --time=30s (It means the test will run 30 seconds.)

       --execute_number=100000  (It  means that after running 100000 commands,
       the test will exit.)

   Dump statistic information periodically.
       The user can use "--stat_freq=" or "-S" to specify the frequency.

       For example:

       --stat_freq=20s

       Memslap will dump the statistics of the commands (get and set)  at  the
       frequency of every 20 seconds.

       For  more  information  on the format of dumping statistic information,
       refer to Format of Output section.

   Multi-get
       The user can use "--division=" or "-d" to specify multi-get keys count.
       Memslap  by  default does single get with TCP. Memslap also testss data
       verification and expire-time verification for multi-get.

       Memslap testss multi-get with both TCP and UDP. Because of the  differ-
       ent implementation of the ASCII protocol and binary protocol, there are
       some differences between the two.  For  the  ASCII  protocol,  memaslap
       sends  one  multi-get  to  the  server  once.  For the binary protocol,
       memaslap sends several single get commands together as multi-get to the
       server.

   UDP and TCP
       Memslap  testss  both UDP and TCP. For TCP, memaslap does not reconnect
       the memcached server if socket connections are lost. If all the  socket
       connections  are  lost or memcached server crashes, memaslap will exit.
       If the user specifies the --reconnect option  when  socket  connections
       are lost, it will reconnect them.

       User  can  use --udp to enable the UDP feature, but UDP comes with some
       limitations:

       UDP cannot set data more than 1400 bytes.

       UDP is not testsed by the binary protocol because the  binary  protocol
       of memcached does not tests that.

       UDP doesnt tests reconnection.

   Facebook test
       Set  data  with  TCP  and  multi-get  with  UDP.  Specify the following
       options:

       "--facebook --division=50"

       If you want to create thousands of TCP connections, specify the

       "--conn_sock=" option.

       For example: --facebook --division=50 --conn_sock=200

       The above command means that memaslap will do facebook test, each  con-
       currency has 200 socket TCP connections and one UDP socket.

       Memslap  sets  objects  with  the TCP socket, and multi-gets 50 objects
       once with the UDP socket.

       If you specify "--division=50", the key size must be less that 25 bytes
       because the UDP packet size is 1400 bytes.

   Replication test
       For  replication  test,  the  user  must specify at least two memcached
       servers.  The user can use rep_write= option to enable feature.

       For example:

       --servers=10.1.1.1:11211,10.1.1.2:11212 rep_write=2

       The above command means that there are 2 replication memcached servers,
       memaslap  will  set  objects to both server 0 and server 1, get objects
       which are set to server 0 before from server 1, and  also  get  objects
       which  are  set  to server 1 before from server 0. If server 0 crashes,
       memaslap will only get objects from server 1. If server 0 comes back to
       life  again,  memaslap  will  reconnect  server 0. If both server 0 and
       server 1 crash, memaslap will exit.

   Supports thousands of TCP connections
       Start memaslap with "--conn_sock=" or "-n" to enable this feature. Make
       sure that your system can tests opening thousands of files and creating
       thousands of sockets. However, this feature does not tests reconnection
       if sockets disconnect.

       For example:

       --threads=8 --concurrency=128 --conn_sock=128

       The  above command means that memaslap starts up 8 threads, each thread
       has 16 concurrencies, each concurrency has 128 TCP socket  connections,
       and the total number of TCP socket connections is 128 * 128 = 16384.

   Supports binary protocol
       Start  memaslap with "--binary" or "-B" options to enable this feature.
       It testss all the above features except UDP, because  the  latest  mem-
       cached 1.3.3 does not implement binary UDP protocol.

       For example:

       --binary

       Since  memcached  1.3.3 doesn't implement binary UDP protocol, memaslap
       does not tests  UDP.  In  addition,  memcached  1.3.3  does  not  tests
       multi-get.  If you specify "--division=50" option, it just sends 50 get
       commands together as mulit-get to the server.

CONFIGURATION FILE
       This section describes  the  format  of  the  configuration  file.   By
       default  when  no  configuration  file  is specified memaslap reads the
       default one located at ~/.memaslap.cnf.

       Below is a sample configuration file:

          ---------------------------------------------------------------------------
          #comments should start with '#'
          #key
          #start_len end_len proportion
          #
          #key length range from start_len to end_len
          #start_len must be equal to or greater than 16
          #end_len must be equal to or less than 250
          #start_len must be equal to or greater than end_len
          #memaslap will generate keys according to the key range
          #proportion: indicates keys generated from one range accounts for the total
          generated keys
          #
          #example1: key range 16~100 accounts for 80%
          #          key range 101~200 accounts for 10%
          #          key range 201~250 accounts for 10%
          #          total should be 1 (0.8+0.1+0.1 = 1)
          #
          #          16 100 0.8
          #          101 200 0.1
          #          201 249 0.1
          #
          #example2: all keys length are 128 bytes
          #
          #          128 128 1
          key
          128 128 1
          #value
          #start_len end_len proportion
          #
          #value length range from start_len to end_len
          #start_len must be equal to or greater than 1
          #end_len must be equal to or less than 1M
          #start_len must be equal to or greater than end_len
          #memaslap will generate values according to the value range
          #proportion: indicates values generated from one range accounts for the
          total generated values
          #
          #example1: value range 1~1000 accounts for 80%
          #          value range 1001~10000 accounts for 10%
          #          value range 10001~100000 accounts for 10%
          #          total should be 1 (0.8+0.1+0.1 = 1)
          #
          #          1 1000 0.8
          #          1001 10000 0.1
          #          10001 100000 0.1
          #
          #example2: all value length are 128 bytes
          #
          #          128 128 1
          value
          2048 2048 1
          #cmd
          #cmd_type cmd_proportion
          #
          #currently memaslap only testss get and set command.
          #
          #cmd_type
          #set     0
          #get     1
          #
          #example: set command accounts for 50%
          #         get command accounts for 50%
          #         total should be 1 (0.5+0.5 = 1)
          #
          #         cmd
          #         0    0.5
          #         1    0.5
          cmd
          0    0.1
          1.0 0.9

FORMAT OF OUTPUT
       At the beginning, memaslap displays some configuration  information  as
       follows:

       servers : 127.0.0.1:11211

       threads count: 1

       concurrency: 16

       run time: 20s

       windows size: 10k

       set proportion: set_prop=0.10

       get proportion: get_prop=0.90

   Where
       servers : "servers"
          The servers used by memaslap.

       threads count
          The number of threads memaslap runs with.

       concurrency
          The number of concurrencies memaslap runs with.

       run time
          How long to run memaslap.

       windows size
          The task window size of each concurrency.

       set proportion
          The proportion of set command.

       get proportion
          The proportion of get command.

       The output of dynamic statistics is something like this:

          ---------------------------------------------------------------------------------------------------------------------------------
          Get Statistics
          Type  Time(s)  Ops   TPS(ops/s)  Net(M/s)  Get_miss  Min(us)  Max(us)
          Avg(us)  Std_dev    Geo_dist
          Period   5   345826  69165     65.3      0         27      2198     203
          95.43      177.29
          Global  20  1257935  62896     71.8      0         26      3791     224
          117.79     192.60


          Set Statistics
          Type  Time(s)  Ops   TPS(ops/s)  Net(M/s)  Get_miss  Min(us)  Max(us)
          Avg(us)  Std_dev    Geo_dist
          Period   5    38425   7685      7.3       0         42      628     240
          88.05      220.21
          Global   20   139780  6989      8.0       0         37      3790    253
          117.93     224.83


          Total Statistics
          Type  Time(s)  Ops   TPS(ops/s)  Net(M/s)  Get_miss  Min(us)  Max(us)
          Avg(us)  Std_dev    Geo_dist
          Period   5   384252   76850     72.5      0        27      2198     207
          94.72      181.18
          Global  20  1397720   69886     79.7      0        26      3791     227
          117.93     195.60
          ---------------------------------------------------------------------------------------------------------------------------------

   Where
       Get Statistics
          Statistics information of get command

       Set Statistics
          Statistics information of set command

       Total Statistics
          Statistics information of both get and set command

       Period
          Result within a period

       Global
          Accumulated results

       Ops
          Total operations

       TPS
          Throughput, operations/second

       Net
          The rate of network

       Get_miss
          How many objects cant be gotten

       Min
          The minimum response time

       Max
          The maximum response time

       Avg:
          The average response time

       Std_dev
          Standard deviation of response time

       Geo_dist
          Geometric distribution based on natural exponential function

       At the end, memaslap will output something like this:

          ---------------------------------------------------------------------------------------------------------------------------------
          Get Statistics (1257956 events)
            Min:        26
            Max:      3791
            Avg:       224
            Geo:    192.60
            Std:    116.23
                            Log2 Dist:
                              4:        0       10    84490   215345
                              8:   484890   459823    12543      824
                             12:       31

           Set Statistics (139782 events)
              Min:        37
              Max:      3790
              Avg:       253
              Geo:    224.84
              Std:    116.83
              Log2 Dist:
                4:        0        0     4200 16988
                8:    50784    65574 2064      167
                12:        5

            Total Statistics (1397738 events)
                Min:        26
                Max:      3791
                Avg:       227
                Geo:    195.60
                Std:    116.60
                Log2 Dist:
                  4:        0       10    88690   232333
                  8:   535674   525397    14607      991
                  12:       36

          cmd_get: 1257969
          cmd_set: 139785
          get_misses: 0
          verify_misses: 0
          verify_failed: 0
          expired_get: 0
          unexpired_unget: 0
          written_bytes: 242516030
          read_bytes: 1003702556
          object_bytes: 152086080
          packet_disorder: 0
          packet_drop: 0
          udp_timeout: 0

          Run time: 20.0s Ops: 1397754 TPS: 69817 Net_rate: 59.4M/s
          ---------------------------------------------------------------------------------------------------------------------------------

   Where
       Get Statistics
          Get statistics of response time

       Set Statistics
          Set statistics of response time

       Total Statistics
          Both get and set statistics of response time

       Min
          The accumulated and minimum response time

       Max
          The accumulated and maximum response time

       Avg
          The accumulated and average response time

       Std
          Standard deviation of response time

       Log2 Dist
          Geometric distribution based on logarithm 2

       cmd_get
          Total get commands done

       cmd_set
          Total set commands done

       get_misses
          How many objects cant be gotten from server

       verify_misses
          How many objects need to verify but cant get them

       verify_failed
          How many objects with insistent value

       expired_get
          How many objects are expired but we get them

       unexpired_unget
          How many objects are unexpired but we cant get them

       written_bytes
          Total written bytes

       read_bytes
          Total read bytes

       object_bytes
          Total object bytes

       packet_disorder
          How many UDP packages are disorder

       packet_drop
          How many UDP packages are lost

       udp_timeout
          How many times UDP time out happen

       Run time
          Total run time

       Ops
          Total operations

       TPS
          Throughput, operations/second

       Net_rate
          The average rate of network

OPTIONS
       -s, --servers=
              List  one or more servers to connect. Servers count must be less
              than  threads   count.   e.g.:   --servers=localhost:1234,local-
              host:11211

       -T, --threads=
              Number  of  threads  to  startup,  better  equal to CPU numbers.
              Default 8.

       -c, --concurrency=
              Number of concurrency to simulate with load. Default 128.

       -n, --conn_sock=
              Number of TCP socks per concurrency. Default 1.

       -x, --execute_number=
              Number of operations(get and set) to execute for the given test.
              Default 1000000.

       -t, --time=
              How long the test to run, suffix: s-seconds, m-minutes, h-hours,
              d-days e.g.: --time=2h.

       -F, --cfg_cmd=
              Load the configure file to get command,key and  value  distribu-
              tion list.

       -w, --win_size=
              Task  window  size  of  each  concurrency,  suffix:  K,  M e.g.:
              --win_size=10k.  Default 10k.

       -X, --fixed_size=
              Fixed length of value.

       -v, --verify=
              The proportion of date verification, e.g.: --verify=0.01

       -d, --division=
              Number of keys to multi-get once. Default 1, means single get.

       -S, --stat_freq=
              Frequency of dumping statistic information.  suffix:  s-seconds,
              m-minutes, e.g.: --resp_freq=10s.

       -e, --exp_verify=
              The  proportion  of  objects  with expire time, e.g.: --exp_ver-
              ify=0.01.  Default no object with expire time

       -o, --overwrite=
              The  proportion  of  objects  need  overwrite,   e.g.:   --over-
              write=0.01.  Default never overwrite object.

       -R, --reconnect
              Reconnect  tests,  when  connection  is closed it will be recon-
              nected.

       -U, --udp
              UDP tests, default memaslap uses TCP, TCP port and UDP  port  of
              server must be same.

       -a, --facebook
              Whether  it  enables  facebook  test  feature,  set with TCP and
              multi-get with UDP.

       -B, --binary
              Whether it enables binary protocol. Default with ASCII protocol.

       -P, --tps=
              Expected throughput, suffix: K, e.g.: --tps=10k.

       -p, --rep_write=
              The first nth servers can write data, e.g.: --rep_write=2.

       -b, --verbose
              Whether it outputs detailed information when verification fails.

       -h, --help
              Display this message and then exit.

       -V, --version
              Display the version of the application and then exit.

EXAMPLES
       memaslap -s 127.0.0.1:11211 -S 5s

       memaslap -s 127.0.0.1:11211 -t 2m -v 0.2 -e 0.05 -b

       memaslap -s 127.0.0.1:11211 -F config -t 2m -w 40k -S 20s -o 0.2

       memaslap -s 127.0.0.1:11211 -F config -t 2m -T 4 -c 128 -d 20 -P 40k

       memaslap -s 127.0.0.1:11211 -F config -t 2m -d 50 -a -n 40

       memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m

       memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m -p 2

HOME
       To find out more information please check: http://libmemcached.org/

AUTHORS
       Mingqiang  Zhuang  <mingqiangzhuang@hengtiansoft.com>  (Schooner  Tech-
       nolgy) Brian Aker, <brian@tangent.org>


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+----------------------+
       |ATTRIBUTE TYPE |   ATTRIBUTE VALUE    |
       +---------------+----------------------+
       |Availability   | library/libmemcached |
       +---------------+----------------------+
       |Stability      | Uncommitted          |
       +---------------+----------------------+
SEE ALSO
       memcached(1) libmemcached(3)

AUTHOR
       Brian Aker

COPYRIGHT
       2011-2013, Brian Aker DataDifferential, http://datadifferential.com/



NOTES
       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source     was     downloaded    from     https://launchpad.net/libmem-
       cached/1.0/1.0.18/+download/libmemcached-1.0.18.tar.gz

       Further information about this software can be found on the open source
       community website at http://libmemcached.org/libMemcached.html.



1.0.18                         February 09, 2014                   MEMASLAP(1)