git.m6w6.name Git - awesomized/libmemcached/blob - docs/source/bin/memaslap.rst

   1 ==================================================
   2 memaslap - Load testing  and benchmarking a server
   3 ==================================================
   4
   5 SYNOPSIS
   6 --------
   7
   8 |client_prefix|\aslap [options]
   9
  10 .. program:: memaslap
  11
  12 .. option:: --help
  13 .. option:: --servers
  14
  15 .. envvar:: MEMCACHED_SERVERS
  16
  17 DESCRIPTION
  18 -----------
  19
  20 :program:`memaslap` is a load generation and benchmark tool for memcached
  21 servers. It generates configurable workload such as threads, concurrency,
  22 connections, run time, overwrite, miss rate, key size, value size, get/set
  23 proportion, expected throughput, and so on. Furthermore, it also tests data
  24 verification, expire-time verification, UDP, binary protocol, facebook test,
  25 replication test, multi-get and reconnection, etc.
  26
  27 Memaslap manages network connections like memcached with
  28 libevent. Each thread of memaslap is bound with a CPU core, all
  29 the threads don't communicate with each other, and there are several socket
  30 connections in each thread. Each connection keeps key size distribution,
  31 value size distribution, and command distribution by itself.
  32
  33 You can specify servers via the :option:`memaslap --servers` option or via the
  34 environment variable :envvar:`MEMCACHED_SERVERS`.
  35
  36 FEATURES
  37 --------
  38
  39 Memslap is developed to for the following purposes:
  40
  41 Manages network connections with libevent asynchronously.
  42
  43 Set both TCP and UDP up to use non-blocking IO.
  44
  45 Improves parallelism: higher performance in multi-threads environments.
  46
  47 Improves time efficiency: faster processing speed.
  48
  49 Generates key and value more efficiently; key size distribution and value size distribution are configurable.
  50
  51 Supports get, multi-get, and set commands; command distribution is configurable.
  52
  53 Supports controllable miss rate and overwrite rate.
  54
  55 Supports data and expire-time verification.
  56
  57 Supports dumping statistic information periodically.
  58
  59 Supports thousands of TCP connections.
  60
  61 Supports binary protocol.
  62
  63 Supports facebook test (set with TCP and multi-get with UDP) and replication test.
  64
  65 DETAILS
  66 -------
  67
  68 Effective implementation of network.
  69 ____________________________________
  70
  71 For memaslap, both TCP and UDP use non-blocking network IO. All
  72 the network events are managed by libevent as memcached. The network module
  73 of memaslap is similar to memcached. Libevent can ensure
  74 memaslap can handle network very efficiently.
  75
  76 Effective implementation of multi-threads and concurrency
  77 _________________________________________________________
  78
  79 Memslap has the similar implementation of multi-threads to
  80 memcached. Memslap creates one or more self-governed threads;
  81 each thread is bound with one CPU core if the system tests setting CPU
  82 core affinity.
  83
  84 In addition, each thread has a libevent to manage the events of the network;
  85 each thread has one or more self-governed concurrency; and each
  86 concurrency has one or more socket connections. All the concurrent tasks don't
  87 communicate with each other even though they are in the same thread.
  88
  89 Memslap can create thousands of socket connections, and each
  90 concurrency has tens of socket connections. Each concurrency randomly or
  91 sequentially selects one socket connection from its socket connection pool
  92 to run, so memaslap can ensure each concurrency handles one
  93 socket connection at any given time. Users can specify the number of
  94 concurrency and socket connections of each concurrency according to their
  95 expected workload.
  96
  97 Effective implementation of generating key and value
  98 ____________________________________________________
  99
 100 In order to improve time efficiency and space efficiency,
 101 memaslap creates a random characters table with 10M characters. All the
 102 suffixes of keys and values are generated from this random characters table.
 103
 104 Memslap uses the offset in the character table and the length
 105 of the string to identify a string. It can save much memory.
 106 Each key contains two parts, a prefix and a suffix. The prefix is an
 107 uint64_t, 8 bytes. In order to verify the data set before,
 108 memaslap need to ensure each key is unique, so it uses the prefix to identify
 109 a key. The prefix cannot include illegal characters, such as '\r', '\n',
 110 '\0' and ' '. And memaslap has an algorithm to ensure that.
 111
 112 Memslap doesn't generate all the objects (key-value pairs) at
 113 the beginning. It only generates enough objects to fill the task window
 114 (default 10K objects) of each concurrency. Each object has the following
 115 basic information, key prefix, key suffix offset in the character table, key
 116 length, value offset in the character table, and value length.
 117
 118 In the work process, each concurrency sequentially or randomly selects an
 119 object from the window to do set operation or get operation. At the same
 120 time, each concurrency kicks objects out of its window and adds new object
 121 into it.
 122
 123 Simple but useful task scheduling
 124 _________________________________
 125
 126 Memslap uses libevent to schedule all concurrent tasks of
 127 threads, and each concurrency schedules tasks based on the local task
 128 window. Memslap assumes that if each concurrency keeps the same
 129 key distribution, value distribution and commands distribution, from
 130 outside, memaslap keeps all the distribution as a whole.
 131 Each task window includes a lot of objects, each object stores its basic
 132 information, such as key, value, expire time, and so on. At any time, all
 133 the objects in the window keep the same and fixed key and value
 134 distribution. If an object is overwritten, the value of the object will be
 135 updated. Memslap verifies the data or expire-time according to
 136 the object information stored in the task window.
 137
 138 Libevent selects which concurrency to handle based on a specific network
 139 event. Then the concurrency selects which command (get or set) to operate
 140 based on the command distribution. If it needs to kick out an old object and
 141 add a new object, in order to keep the same key and value distribution, the
 142 new object must have the same key length and value length.
 143
 144 If memcached server has two cache layers (memory and SSD), running
 145 memaslap with different window sizes can get different cache
 146 miss rates. If memaslap adds enough objects into the windows at
 147 the beginning, and the cache of memcached cannot store all the objects
 148 initialized, then memaslap will get some objects from the second
 149 cache layer. It causes the first cache layer to miss. So the user can
 150 specify the window size to get the expected miss rate of the first cache
 151 layer.
 152
 153 Useful implementation of multi-servers , UDP, TCP, multi-get and binary protocol
 154 ________________________________________________________________________________
 155
 156 Because each thread is self-governed, memaslap can assign
 157 different threads to handle different memcached servers. This is just one of
 158 the ways in which memaslap tests multiple servers. The only
 159 limitation is that the number of servers cannot be greater than the number
 160 of threads. The other way to test multiple servers is for replication
 161 test. Each concurrency has one socket connection to each memcached server.
 162 For the implementation, memaslap can set some objects to one
 163 memcached server, and get these objects from the other servers.
 164
 165 By default, Memslap does single get. If the user specifies
 166 multi-get option, memaslap will collect enough get commands and
 167 pack and send the commands together.
 168
 169 Memslap tests both the ASCII protocol and binary protocol,
 170 but it runs on the ASCII protocol by default.
 171 Memslap by default runs on the TCP protocol, but it also
 172 tests UDP. Because UDP is unreliable, dropped packages and out-of-order
 173 packages may occur. Memslap creates a memory buffer to handle
 174 these problems. Memslap tries to read all the response data of
 175 one command from the server and reorders the response data. If some packages
 176 get lost, the waiting timeout mechanism can ensure half-baked packages will
 177 be discarded and the next command will be sent.
 178
 179 USAGE
 180 -----
 181
 182 Below are some usage samples:
 183
 184 memaslap -s 127.0.0.1:11211 -S 5s
 185
 186 memaslap -s 127.0.0.1:11211 -t 2m -v 0.2 -e 0.05 -b
 187
 188 memaslap -s 127.0.0.1:11211 -F config -t 2m -w 40k -S 20s -o 0.2
 189
 190 memaslap -s 127.0.0.1:11211 -F config -t 2m -T 4 -c 128 -d 20 -P 40k
 191
 192 memaslap -s 127.0.0.1:11211 -F config -t 2m -d 50 -a -n 40
 193
 194 memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m
 195
 196 memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m -p 2
 197
 198 The user must specify one server at least to run memaslap. The
 199 rest of the parameters have default values, as shown below:
 200
 201 Thread number = 1                     Concurrency = 16
 202
 203 Run time = 600 seconds                Configuration file = NULL
 204
 205 Key size = 64                         Value size = 1024
 206
 207 Get/set = 9:1                         Window size = 10k
 208
 209 Execute number = 0                    Single get = true
 210
 211 Multi-get = false                     Number of sockets of each concurrency = 1
 212
 213 Reconnect = false                     Data verification = false
 214
 215 Expire-time verification = false      ASCII protocol = true
 216
 217 Binary protocol = false               Dumping statistic information periodically = false
 218
 219 Overwrite proportion = 0%             UDP = false
 220
 221 TCP = true                            Limit throughput = false
 222
 223 Facebook test = false                 Replication test = false
 224
 225 Key size, value size and command distribution.
 226 ______________________________________________
 227
 228 All the distributions are read from the configuration file specified by user
 229 with "—cfg_cmd" option. If the user does not specify a configuration file,
 230 memaslap will run with the default distribution (key size = 64,
 231 value size = 1024, get/set = 9:1). For information on how to edit the
 232 configuration file, refer to the "Configuration File" section.
 233
 234 The minimum key size is 16 bytes; the maximum key size is 250 bytes. The
 235 precision of proportion is 0.001. The proportion of distribution will be
 236 rounded to 3 decimal places.
 237
 238 The minimum value size is 1 bytes; the maximum value size is 1M bytes. The
 239 precision of proportion is 0.001. The proportion of distribution will be
 240 rounded to 3 decimal places.
 241 Currently, memaslap only tests set and get commands. And it
 242 testss 100% set and 100% get. For 100% get, it will preset some objects to
 243 the server.
 244
 245 Multi-thread and concurrency
 246 ____________________________
 247
 248 The high performance of memaslap benefits from the special
 249 schedule of thread and concurrency. It's important to specify the proper
 250 number of them. The default number of threads is 1; the default number of
 251 concurrency is 16. The user can use "—threads" and "--concurrency" to
 252 specify these variables.
 253
 254 If the system tests setting CPU affinity and the number of threads
 255 specified by the user is greater than 1, memaslap will try to
 256 bind each thread to a different CPU core. So if you want to get the best
 257 performance memaslap, it is better to specify the number of
 258 thread equal to the number of CPU cores. The number of threads specified by
 259 the user can also be less or greater than the number of CPU cores. Because
 260 of the limitation of implementation, the number of concurrencies could be
 261 the multiple of the number of threads.
 262
 263 1. For 8 CPU cores system
 264
 265 For example:
 266
 267 --threads=2 --concurrency=128
 268
 269 --threads=8 --concurrency=128
 270
 271 --threads=8 --concurrency=256
 272
 273 --threads=12 --concurrency=144
 274
 275 2. For 16 CPU cores system
 276
 277 For example:
 278
 279 --threads=8 --concurrency=128
 280
 281 --threads=16 --concurrency=256
 282
 283 --threads=16 --concurrency=512
 284
 285 --threads=24 --concurrency=288
 286
 287 The memaslap performs very well, when
 288 used to test the performance of memcached servers.
 289 Most of the time, the bottleneck is the network or
 290 the server. If for some reason the user wants to
 291 limit the performance of memaslap, there
 292 are two ways to do this:
 293
 294 Decrease the number of threads and concurrencies.
 295 Use the option "--tps" that memaslap
 296 provides to limit the throughput. This option allows
 297 the user to get the expected throughput. For
 298 example, assume that the maximum throughput is 50
 299 kops/s for a specific configuration, you can specify
 300 the throughput equal to or less than the maximum
 301 throughput using "--tps" option.
 302
 303 Window size
 304 ___________
 305
 306 Most of the time, the user does not need to specify the window size. The
 307 default window size is 10k. For Schooner Memcached, the user can specify
 308 different window sizes to get different cache miss rates based on the test
 309 case. Memslap testss cache miss rate between 0% and 100%.
 310 If you use this utility to test the performance of Schooner Memcached, you
 311 can specify a proper window size to get the expected cache miss rate. The
 312 formula for calculating window size is as follows:
 313
 314 Assume that the key size is 128 bytes, and the value size is 2048 bytes, and
 315 concurrency=128.
 316
 317 1. Small cache cache_size=1M, 100% cache miss (all data get from SSD).
 318 win_size=10k
 319
 320 2. cache_size=4G
 321
 322 (1). cache miss rate 0%
 323
 324 win_size=8k
 325
 326 (2). cache miss rate 5%
 327
 328 win_size=11k
 329
 330 3. cache_size=16G
 331
 332 (1). cache miss rate 0%
 333
 334 win_size=32k
 335
 336 (2). cache miss
 337
 338 rate 5%
 339
 340 win_size=46k
 341
 342 The formula for calculating window size for cache miss rate 0%:
 343
 344 cache_size / concurrency / (key_size + value_size) \* 0.5
 345
 346 The formula for calculating window size for cache miss rate 5%:
 347
 348 cache_size / concurrency / (key_size + value_size) \* 0.7
 349
 350 Verification
 351 ____________
 352
 353 Memslap testss both data verification and expire-time
 354 verification. The user can use "--verify=" or "-v" to specify the proportion
 355 of data verification. In theory, it testss 100% data verification. The
 356 user can use "--exp_verify=" or "-e" to specify the proportion of
 357 expire-time verification. In theory, it testss 100% expire-time
 358 verification. Specify the "--verbose" options to get more detailed error
 359 information.
 360
 361 For example: --exp_verify=0.01 –verify=0.1 , it means that 1% of the objects
 362 set with expire-time, 10% of the objects gotten will be verified. If the
 363 objects are gotten, memaslap will verify the expire-time and
 364 value.
 365
 366 multi-servers and multi-config
 367 _______________________________
 368
 369 Memslap testss multi-servers based on self-governed thread.
 370 There is a limitation that the number of servers cannot be greater than the
 371 number of threads. Memslap assigns one thread to handle one
 372 server at least. The user can use the "--servers=" or "-s" option to specify
 373 multi-servers.
 374
 375 For example:
 376
 377 --servers=10.1.1.1:11211,10.1.1.2:11212,10.1.1.3:11213 --threads=6 --concurrency=36
 378
 379 The above command means that there are 6 threads, with each thread having 6
 380 concurrencies and that threads 0 and 3 handle server 0 (10.1.1.1); threads 1
 381 and 4 handle server 1 (10.1.1.2); and thread 2 and 5 handle server 2
 382 (10.1.1.3).
 383
 384 All the threads and concurrencies in memaslap are self-governed.
 385
 386 So is memaslap. The user can start up several
 387 memaslap instances. The user can run memaslap on different client
 388 machines to communicate with the same memcached server at the same. It is
 389 recommended that the user start different memaslap on different
 390 machines using the same configuration.
 391
 392 Run with execute number mode or time mode
 393 _________________________________________
 394
 395 The default memaslap runs with time mode. The default run time
 396 is 10 minutes. If it times out, memaslap will exit. Do not
 397 specify both execute number mode and time mode at the same time; just
 398 specify one instead.
 399
 400 For example:
 401
 402 --time=30s (It means the test will run 30 seconds.)
 403
 404 --execute_number=100000 (It means that after running 100000 commands, the test will exit.)
 405
 406 Dump statistic information periodically.
 407 ________________________________________
 408
 409 The user can use "--stat_freq=" or "-S" to specify the frequency.
 410
 411 For example:
 412
 413 --stat_freq=20s
 414
 415 Memslap will dump the statistics of the commands (get and set) at the frequency of every 20
 416 seconds.
 417
 418 For more information on the format of dumping statistic information, refer to "Format of Output" section.
 419
 420 Multi-get
 421 _________
 422
 423 The user can use "--division=" or "-d" to specify multi-get keys count.
 424 Memslap by default does single get with TCP. Memslap also testss data
 425 verification and expire-time verification for multi-get.
 426
 427 Memslap testss multi-get with both TCP and UDP. Because of
 428 the different implementation of the ASCII protocol and binary protocol,
 429 there are some differences between the two. For the ASCII protocol,
 430 memaslap sends one "multi-get" to the server once. For the
 431 binary protocol, memaslap sends several single get commands
 432 together as "multi-get" to the server.
 433
 434 UDP and TCP
 435 ___________
 436
 437 Memslap testss both UDP and TCP. For TCP,
 438 memaslap does not reconnect the memcached server if socket connections are
 439 lost. If all the socket connections are lost or memcached server crashes,
 440 memaslap will exit. If the user specifies the "--reconnect"
 441 option when socket connections are lost, it will reconnect them.
 442
 443 User can use "--udp" to enable the UDP feature, but UDP comes with some
 444 limitations:
 445
 446 UDP cannot set data more than 1400 bytes.
 447
 448 UDP is not tested by the binary protocol because the binary protocol of
 449 memcached does not tests that.
 450
 451 UDP doesn't tests reconnection.
 452
 453 Facebook test
 454 _____________
 455
 456 Set data with TCP and multi-get with UDP. Specify the following options:
 457
 458 "--facebook --division=50"
 459
 460 If you want to create thousands of TCP connections, specify the
 461
 462 "--conn_sock=" option.
 463
 464 For example: --facebook --division=50 --conn_sock=200
 465
 466 The above command means that memaslap will do facebook test,
 467 each concurrency has 200 socket TCP connections and one UDP socket.
 468
 469 Memslap sets objects with the TCP socket, and multi-gets 50
 470 objects once with the UDP socket.
 471
 472 If you specify "--division=50", the key size must be less that 25 bytes
 473 because the UDP packet size is 1400 bytes.
 474
 475 Replication test
 476 ________________
 477
 478 For replication test, the user must specify at least two memcached servers.
 479 The user can use "—rep_write=" option to enable feature.
 480
 481 For example:
 482
 483 --servers=10.1.1.1:11211,10.1.1.2:11212 –rep_write=2
 484
 485 The above command means that there are 2 replication memcached servers,
 486 memaslap will set objects to both server 0 and server 1, get
 487 objects which are set to server 0 before from server 1, and also get objects
 488 which are set to server 1 before from server 0. If server 0 crashes,
 489 memaslap will only get objects from server 1. If server 0 comes
 490 back to life again, memaslap will reconnect server 0. If both
 491 server 0 and server 1 crash, memaslap will exit.
 492
 493 Supports thousands of TCP connections
 494 _____________________________________
 495
 496 Start memaslap with "--conn_sock=" or "-n" to enable this
 497 feature. Make sure that your system can tests opening thousands of files
 498 and creating thousands of sockets. However, this feature does not tests
 499 reconnection if sockets disconnect.
 500
 501 For example:
 502
 503 --threads=8 --concurrency=128 --conn_sock=128
 504
 505 The above command means that memaslap starts up 8 threads, each
 506 thread has 16 concurrencies, each concurrency has 128 TCP socket
 507 connections, and the total number of TCP socket connections is 128 \* 128 =
 508 16384.
 509
 510 Supports binary protocol
 511 ________________________
 512
 513 Start memaslap with "--binary" or "-B" options to enable this
 514 feature. It testss all the above features except UDP, because the latest
 515 memcached 1.3.3 does not implement binary UDP protocol.
 516
 517 For example:
 518
 519 --binary
 520
 521 Since memcached 1.3.3 doesn't implement binary UDP protocol,
 522 memaslap does not tests UDP. In addition, memcached 1.3.3 does not tests
 523 multi-get. If you specify "--division=50" option, it just sends 50 get
 524 commands together as "multi-get" to the server.
 525
 526 Configuration file
 527 ------------------
 528
 529 This section describes the format of the configuration file.  By default
 530 when no configuration file is specified memaslap reads the default
 531 one located at ~/.memaslap.cnf.
 532
 533 Below is a sample configuration file:
 534
 535 .. code-block:: perl
 536
 537   ---------------------------------------------------------------------------
 538   #comments should start with '#'
 539   #key
 540   #start_len end_len proportion
 541   #
 542   #key length range from start_len to end_len
 543   #start_len must be equal to or greater than 16
 544   #end_len must be equal to or less than 250
 545   #start_len must be equal to or greater than end_len
 546   #memaslap will generate keys according to the key range
 547   #proportion: indicates keys generated from one range accounts for the total
 548   generated keys
 549   #
 550   #example1: key range 16~100 accounts for 80%
 551   #          key range 101~200 accounts for 10%
 552   #          key range 201~250 accounts for 10%
 553   #          total should be 1 (0.8+0.1+0.1 = 1)
 554   #
 555   #          16 100 0.8
 556   #          101 200 0.1
 557   #          201 249 0.1
 558   #
 559   #example2: all keys length are 128 bytes
 560   #
 561   #          128 128 1
 562   key
 563   128 128 1
 564   #value
 565   #start_len end_len proportion
 566   #
 567   #value length range from start_len to end_len
 568   #start_len must be equal to or greater than 1
 569   #end_len must be equal to or less than 1M
 570   #start_len must be equal to or greater than end_len
 571   #memaslap will generate values according to the value range
 572   #proportion: indicates values generated from one range accounts for the
 573   total generated values
 574   #
 575   #example1: value range 1~1000 accounts for 80%
 576   #          value range 1001~10000 accounts for 10%
 577   #          value range 10001~100000 accounts for 10%
 578   #          total should be 1 (0.8+0.1+0.1 = 1)
 579   #
 580   #          1 1000 0.8
 581   #          1001 10000 0.1
 582   #          10001 100000 0.1
 583   #
 584   #example2: all value length are 128 bytes
 585   #
 586   #          128 128 1
 587   value
 588   2048 2048 1
 589   #cmd
 590   #cmd_type cmd_proportion
 591   #
 592   #currently memaslap only testss get and set command.
 593   #
 594   #cmd_type
 595   #set     0
 596   #get     1
 597   #
 598   #example: set command accounts for 50%
 599   #         get command accounts for 50%
 600   #         total should be 1 (0.5+0.5 = 1)
 601   #
 602   #         cmd
 603   #         0    0.5
 604   #         1    0.5
 605   cmd
 606   0    0.1
 607   1.0 0.9
 608
 609 Format of output
 610 ----------------
 611
 612 At the beginning, memaslap displays some configuration information as follows:
 613
 614 servers : 127.0.0.1:11211
 615
 616 threads count: 1
 617
 618 concurrency: 16
 619
 620 run time: 20s
 621
 622 windows size: 10k
 623
 624 set proportion: set_prop=0.10
 625
 626 get proportion: get_prop=0.90
 627
 628 Where
 629 _____
 630
 631 servers : "servers"
 632
 633  The servers used by memaslap.
 634
 635 threads count
 636
 637  The number of threads memaslap runs with.
 638
 639 concurrency
 640
 641  The number of concurrencies memaslap runs with.
 642
 643 run time
 644
 645  How long to run memaslap.
 646
 647 windows size
 648
 649  The task window size of each concurrency.
 650
 651 set proportion
 652
 653  The proportion of set command.
 654
 655 get proportion
 656
 657  The proportion of get command.
 658
 659 The output of dynamic statistics is something like this:
 660
 661 .. code-block:: perl
 662
 663   ---------------------------------------------------------------------------------------------------------------------------------
 664   Get Statistics
 665   Type  Time(s)  Ops   TPS(ops/s)  Net(M/s)  Get_miss  Min(us)  Max(us)
 666   Avg(us)  Std_dev    Geo_dist
 667   Period   5   345826  69165     65.3      0         27      2198     203
 668   95.43      177.29
 669   Global  20  1257935  62896     71.8      0         26      3791     224
 670   117.79     192.60
 671   Set Statistics
 672
 673   Type  Time(s)  Ops   TPS(ops/s)  Net(M/s)  Get_miss  Min(us)  Max(us)
 674   Avg(us)  Std_dev    Geo_dist
 675   Period   5    38425   7685      7.3       0         42      628     240
 676   88.05      220.21
 677   Global   20   139780  6989      8.0       0         37      3790    253
 678   117.93     224.83
 679   Total Statistics
 680
 681   Type  Time(s)  Ops   TPS(ops/s)  Net(M/s)  Get_miss  Min(us)  Max(us)
 682   Avg(us)  Std_dev    Geo_dist
 683   Period   5   384252   76850     72.5      0        27      2198     207
 684   94.72      181.18
 685   Global  20  1397720   69886     79.7      0        26      3791     227
 686   117.93     195.60
 687   ---------------------------------------------------------------------------------------------------------------------------------
 688
 689 Where
 690 _____
 691
 692 Get Statistics
 693
 694  Statistics information of get command
 695
 696 Set Statistics
 697
 698  Statistics information of set command
 699
 700 Total Statistics
 701
 702  Statistics information of both get and set command
 703
 704 Period
 705
 706  Result within a period
 707
 708 Global
 709
 710  Accumulated results
 711
 712 Ops
 713
 714  Total operations
 715
 716 TPS
 717
 718  Throughput, operations/second
 719
 720 Net
 721
 722  The rate of network
 723
 724 Get_miss
 725
 726  How many objects can't be gotten
 727
 728 Min
 729
 730  The minimum response time
 731
 732 Max
 733
 734  The maximum response time
 735
 736 Avg:
 737
 738  The average response time
 739
 740 Std_dev
 741
 742  Standard deviation of response time
 743
 744 Geo_dist
 745
 746  Geometric distribution based on natural exponential function
 747
 748 At the end, memaslap will output something like this:
 749
 750 .. code-block:: perl
 751
 752    ---------------------------------------------------------------------------------------------------------------------------------
 753    Get Statistics (1257956 events)
 754      Min:        26
 755      Max:      3791
 756      Avg:       224
 757      Geo:    192.60
 758      Std:    116.23
 759                      Log2 Dist:
 760                        4:        0       10    84490   215345
 761                        8:   484890   459823    12543      824
 762                       12:       31
 763
 764     Set Statistics (139782 events)
 765        Min:        37
 766        Max:      3790
 767        Avg:       253
 768        Geo:    224.84
 769        Std:    116.83
 770        Log2 Dist:
 771          4:        0        0     4200 16988
 772          8:    50784    65574 2064      167
 773          12:        5
 774
 775      Total Statistics (1397738 events)
 776          Min:        26
 777          Max:      3791
 778          Avg:       227
 779          Geo:    195.60
 780          Std:    116.60
 781          Log2 Dist:
 782            4:        0       10    88690   232333
 783            8:   535674   525397    14607      991
 784            12:       36
 785
 786    cmd_get: 1257969
 787    cmd_set: 139785
 788    get_misses: 0
 789    verify_misses: 0
 790    verify_failed: 0
 791    expired_get: 0
 792    unexpired_unget: 0
 793    written_bytes: 242516030
 794    read_bytes: 1003702556
 795    object_bytes: 152086080
 796    packet_disorder: 0
 797    packet_drop: 0
 798    udp_timeout: 0
 799
 800    Run time: 20.0s Ops: 1397754 TPS: 69817 Net_rate: 59.4M/s
 801    ---------------------------------------------------------------------------------------------------------------------------------
 802
 803 Where
 804 _____
 805
 806 Get Statistics
 807
 808  Get statistics of response time
 809
 810 Set Statistics
 811
 812  Set statistics of response time
 813
 814 Total Statistics
 815
 816  Both get and set statistics of response time
 817
 818 Min
 819
 820  The accumulated and minimum response time
 821
 822 Max
 823
 824  The accumulated and maximum response time
 825
 826 Avg
 827
 828  The accumulated and average response time
 829
 830 Std
 831
 832  Standard deviation of response time
 833
 834 Log2 Dist
 835
 836  Geometric distribution based on logarithm 2
 837
 838 cmd_get
 839
 840  Total get commands done
 841
 842 cmd_set
 843
 844  Total set commands done
 845
 846 get_misses
 847
 848  How many objects can't be gotten from server
 849
 850 verify_misses
 851
 852  How many objects need to verify but can't get them
 853
 854 verify_failed
 855
 856  How many objects with insistent value
 857
 858 expired_get
 859
 860  How many objects are expired but we get them
 861
 862 unexpired_unget
 863
 864  How many objects are unexpired but we can't get them
 865
 866 written_bytes
 867
 868  Total written bytes
 869
 870 read_bytes
 871
 872  Total read bytes
 873
 874 object_bytes
 875
 876  Total object bytes
 877
 878 packet_disorder
 879
 880  How many UDP packages are disorder
 881
 882 packet_drop
 883
 884  How many UDP packages are lost
 885
 886 udp_timeout
 887
 888  How many times UDP time out happen
 889
 890 Run time
 891
 892  Total run time
 893
 894 Ops
 895
 896  Total operations
 897
 898 TPS
 899
 900  Throughput, operations/second
 901
 902 Net_rate
 903
 904  The average rate of network
 905
 906 OPTIONS
 907 -------
 908
 909 -s, --servers=
 910     List one or more servers to connect. Servers count must be less than
 911     threads count. e.g.: --servers=localhost:1234,localhost:11211
 912
 913 -T, --threads=
 914     Number of threads to startup, better equal to CPU numbers. Default 8.
 915
 916 -c, --concurrency=
 917     Number of concurrency to simulate with load. Default 128.
 918
 919 -n, --conn_sock=
 920     Number of TCP socks per concurrency. Default 1.
 921
 922 -x, --execute_number=
 923     Number of operations(get and set) to execute for the
 924     given test. Default 1000000.
 925
 926 -t, --time=
 927     How long the test to run, suffix: s-seconds, m-minutes, h-hours,
 928     d-days e.g.: --time=2h.
 929
 930 -F, --cfg_cmd=
 931     Load the configure file to get command,key and value distribution list.
 932
 933 -w, --win_size=
 934     Task window size of each concurrency, suffix: K, M e.g.: --win_size=10k.
 935     Default 10k.
 936
 937 -X, --fixed_size=
 938     Fixed length of value.
 939
 940 -v, --verify=
 941     The proportion of date verification, e.g.: --verify=0.01
 942
 943 -d, --division=
 944     Number of keys to multi-get once. Default 1, means single get.
 945
 946 -S, --stat_freq=
 947     Frequency of dumping statistic information. suffix: s-seconds,
 948     m-minutes, e.g.: --resp_freq=10s.
 949
 950 -e, --exp_verify=
 951     The proportion of objects with expire time, e.g.: --exp_verify=0.01.
 952     Default no object with expire time
 953
 954 -o, --overwrite=
 955     The proportion of objects need overwrite, e.g.: --overwrite=0.01.
 956     Default never overwrite object.
 957
 958 -R, --reconnect
 959     Reconnect tests, when connection is closed it will be reconnected.
 960
 961 -U, --udp
 962     UDP tests, default memaslap uses TCP, TCP port and UDP port of
 963     server must be same.
 964
 965 -a, --facebook
 966     Whether it enables facebook test feature, set with TCP and multi-get with UDP.
 967
 968 -B, --binary
 969     Whether it enables binary protocol. Default with ASCII protocol.
 970
 971 -P, --tps=
 972     Expected throughput, suffix: K, e.g.: --tps=10k.
 973
 974 -p, --rep_write=
 975     The first nth servers can write data, e.g.: --rep_write=2.
 976
 977 -b, --verbose
 978     Whether it outputs detailed information when verification fails.
 979
 980 -h, --help
 981     Display this message and then exit.
 982
 983 -V, --version
 984     Display the version of the application and then exit.
 985
 986 EXAMPLES
 987 --------
 988
 989 memaslap -s 127.0.0.1:11211 -S 5s
 990
 991 memaslap -s 127.0.0.1:11211 -t 2m -v 0.2 -e 0.05 -b
 992
 993 memaslap -s 127.0.0.1:11211 -F config -t 2m -w 40k -S 20s -o 0.2
 994
 995 memaslap -s 127.0.0.1:11211 -F config -t 2m -T 4 -c 128 -d 20 -P 40k
 996
 997 memaslap -s 127.0.0.1:11211 -F config -t 2m -d 50 -a -n 40
 998
 999 memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m
1000
1001 memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m -p 2
1002
1003 NOTES
1004 -----
1005
1006 .. include:: common/note_program_prefix.rst
1007 .. include:: common/note_contrib_options.rst
1008
1009 SEE ALSO
1010 --------
1011
1012 .. only:: man
1013
1014   :manpage:`memcached(1)` :manpage:`libmemcached(3)`