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Updated: Thursday, June 13, 2019
 
 

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 don't 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  doesn't  generate  all  the  objects  (key-value pairs) at the
       beginning. It only generates enough objects to  fill  the  task  window
       (default  10K objects) of each concurrency. Each object has the follow-
       ing 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 configura-
       tion 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. It's 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 spec-
       ify 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 maximum throughput is 50 kops/s for a specific configuration,
       you can specify 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 doesn't 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 can't 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 can't be gotten from server

       verify_misses
          How many objects need to verify but can't 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 can't 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)