Mutilate

Mutilate is a memcached load generator designed for high request rates, good tail-latency measurements, and realistic request stream generation.

Requirements

1. A C++0x compiler
2. scons
3. libevent
4. gengetopt
5. zeromq (optional)

Mutilate has only been thoroughly tested on Ubuntu 11.10. We'll flesh out compatibility over time.

Building

apt-get install scons libevent-dev gengetopt libzmq-dev
scons

Usage

Type './mutilate -h' for a full list of command-line options. At minimum, a server must be specified.

$ ./mutilate -s localhost
#type       avg     min     1st     5th    10th    90th    95th    99th
read       52.4    41.0    43.1    45.2    48.1    55.8    56.6    71.5
update      0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0
op_q        1.5     1.0     1.0     1.1     1.1     1.9     2.0     2.0

Total QPS = 18416.6 (92083 / 5.0s)

Misses = 0 (0.0%)

RX   22744501 bytes :    4.3 MB/s
TX    3315024 bytes :    0.6 MB/s

Mutilate reports the latency (average, minimum, and various percentiles) for get and set commands, as well as achieved QPS and network goodput.

To achieve high request rate, you must configure mutilate to use multiple threads, multiple connections, connection pipelining, or remote agents.

$ ./mutilate -s zephyr2-10g -T 24 -c 8
#type       avg     min     1st     5th    10th    90th    95th    99th
read      598.8    86.0   437.2   466.6   482.6   977.0  1075.8  1170.6
update      0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0
op_q        1.5     1.0     1.0     1.1     1.1     1.9     1.9     2.0

Total QPS = 318710.8 (1593559 / 5.0s)

Misses = 0 (0.0%)

RX  393609073 bytes :   75.1 MB/s
TX   57374136 bytes :   10.9 MB/s

Command-line Options

Usage: mutilate -s server[:port] [options]

"High-performance" memcached benchmarking tool

-h, --help Print help and exit --version Print version and exit -v, --verbose Verbosity. Repeat for more verbose. --quiet Disable log messages.

Basic options: -s, --server=STRING Memcached server hostname[:port]. Repeat to specify multiple servers. -q, --qps=INT Target aggregate QPS. 0 = peak QPS. (default=0') -t, --time=INT Maximum time to run (seconds). (default=5') -K, --keysize=STRING Length of memcached keys (distribution). (default=30') -V, --valuesize=STRING Length of memcached values (distribution). (default=200') -r, --records=INT Number of memcached records to use. If multiple memcached servers are given, this number is divided by the number of servers. (default=10000') -u, --update=FLOAT Ratio of set:get commands. (default=0.0')

Advanced options: -T, --threads=INT Number of threads to spawn. (default=1') -c, --connections=INT Connections to establish per server. (default=1') -d, --depth=INT Maximum depth to pipeline requests. (default=1') -R, --roundrobin Assign threads to servers in round-robin fashion. By default, each thread connects to every server. -i, --iadist=STRING Inter-arrival distribution (distribution). Note: The distribution will automatically be adjusted to match the QPS given by --qps. (default=exponential') --noload Skip database loading. --loadonly Load database and then exit. -B, --blocking Use blocking epoll(). May increase latency. -D, --no_nodelay Don't use TCP_NODELAY. -w, --warmup=INT Warmup time before starting measurement. -W, --wait=INT Time to wait after startup to start measurement. -S, --search=N:X Search for the QPS where N-order statistic < Xus. (i.e. --search 95:1000 means find the QPS where 95% of requests are faster than 1000us). --scan=min:max:step Scan latency across QPS rates from min to max.

Agent-mode options: -A, --agentmode Run client in agent mode. -a, --agent=host Enlist remote agent. -l, --lambda_mul=INT Lambda multiplier. Increases share of QPS for this client. (default=`1')

Some options take a 'distribution' as an argument. Distributions are specified by [:[,...]]. Parameters are not required. The following distributions are supported:

[fixed:] Always generates . uniform: Uniform distribution between 0 and . normal:, Normal distribution. exponential: Exponential distribution. pareto:,, Generalized Pareto distribution. gev:,, Generalized Extreme Value distribution.

To recreate the Facebook "ETC" request stream from [1], the following hard-coded distributions are also provided:

fb_value = a hard-coded discrete and GPareto PDF of value sizes fb_key = "gev:30.7984,8.20449,0.078688", key-size distribution fb_ia = "pareto:0.0,16.0292,0.154971", inter-arrival time dist.

[1] Berk Atikoglu et al., Workload Analysis of a Large-Scale Key-Value Store, SIGMETRICS 2012