ssbench 0.1.0

Scenarios

A “scenario” (sometimes called a “CRUD scenario”) is a utf8-encoded JSON file defining a benchmark run. Specifically, it defines:

• A name for the scenario (an arbitrary string)

• A sizes list of “object size” classes. Each object size class has a name, a size_min minimum object size, a size_max maximum object size (in bytes), and an optional crud_profile for just this size. If crud_profile is not given for a size, the top-level crud_profile will be used. The crud_profile here is just like the top-level one, an array of 4 numbers whose relative sizes determine the percent chance of a Create, Read, Update, or Delete operation. Objects created or updated within an object size class will have a size (in bytes) chosen at random uniformly between the minimum and maximum sizes.

• An initial_files dictionary of initial file-counts per size class. Each size class can have zero or more objects uploaded prior to the benchmark run itself. The proportion of initial files also defines the probability distribution of object sizes during the benchmark run itself. So if a particular object size class is not included in initial_files or has a value of 0 in initial_files, then no objects in that size class will be used during the benchmark run.

• An operation_count of operations to perform during the benchmark run. An operation is either a CREATE, READ, UPDATE, or DELETE of an object. This value may be overridden for any given run with the -o COUNT flag to ssbench-master run-scenario.

• A crud_profile which determines the distribution of each kind of operation. For instance, [3, 4, 2, 2] would mean 27% CREATE, 36% READ, 18% UPDATE, and 18% DELETE.

• A user_count which determines the maxiumum client concurrency during the benchmark run. The user is responsible for ensuring there are enough workers running to support the scenario’s defined user_count. (Each ssbench-worker process uses gevent to achive very efficeint concurrency for the benchmark client requests.) This value may be overridden for any given run with the -u COUNT flag to ssbench-master run-scenario.

• A container_count which determines how many Swift containers are used for the benchmark run. This key is optional in the scenario file and defaults to 100. This value may be overridden for any given run with the -c COUNT flag to ssbench-master run-scenario.

• A container_concurrency value which determines the level of client concurrency used by ssbench-master to create the benchmark containers. This value is optional and defaults to 10.

For each operation of the benchmark run, a size category is first chosen based on the relative counts for each size category in the initial_files dictionary. This probability for each size category appears under the “% Ops” column in the report. Then an operation type is chosen based on that size category’s CRUD profile (which can be individually specified or may be inherited from the “top level” CRUD profile).

If each size category has its own CRUD profile, then the overall CRUD profile of the benchmark run will be a weighted average between the values in the “% Ops” column and the CRUD profile of each size category. This weighted average CRUD profile is included in the report on the “CRUD weighted average” line.

ssbench comes with a few canned scenarios, but users are encouraged to experiment and define their own.

Here is an example JSON scenario file:

{
  "name": "Small test scenario",
  "sizes": [{
    "name": "tiny",
    "size_min": 4096,
    "size_max": 65536
  }, {
    "name": "small",
    "size_min": 100000,
    "size_max": 200000
  }],
  "initial_files": {
    "tiny": 100,
    "small": 10
  },
  "operation_count": 500,
  "crud_profile": [3, 4, 2, 2],
  "user_count": 7
}

Beware: hand-editing JSON is error-prone. Watch out for trailing commas, in particular.

Installation

ssbench has been developed for and tested with Python 2.7 (Python 2.6 might work if the argparse module is installed, but I haven’t tested that.)

You will first need to install libevent and Beanstalkd. On Ubuntu, the packages are libevent-dev and beanstalkd. On the Mac, they may both be installed with Homebrew. I have not tested ssbench against gevent v1.x, but according to a dated blog post, gevent v1.x will bundle libev and not require the installation of libevent or libev_. If you try ssbench with gevent 1.x, please let me know how that goes…

You may install this module (ssbench) and its Python module dependencies via pip.

You will also need an OpenStack Swift cluster to benchmark.

Usage

The ssbench-worker script:

$ ssbench-worker --help
usage: ssbench-worker [-h] [--qhost QHOST] [--qport QPORT] [-c CONCURRENCY]
                      [--retries RETRIES] [-p COUNT] [-v]
                      worker_id

Benchmark your Swift installation

positional arguments:
  worker_id             An integer ID number; must be unique among all workers

optional arguments:
  -h, --help            show this help message and exit
  --qhost QHOST         beanstalkd host (default: 127.0.0.1)
  --qport QPORT         beanstalkd port (default: 11300)
  -c CONCURRENCY, --concurrency CONCURRENCY
                        Maximum concurrency this worker will provide.
                        (default: 256)
  --retries RETRIES     Maximum number of times to retry a job. (default: 10)
  -p COUNT, --profile-count COUNT
                        Profile COUNT work jobs, starting with the first.
                        (default: 0)
  -v, --verbose         Enable more verbose output. (default: False)

Basic usage of ssbench-master (requires one sub-command of run-scenario to actually run a benchmark scenario, or report-scenario to report on an existing scenario result data file:

usage: ssbench-master [-h] [-v] {run-scenario,report-scenario} ...

Benchmark your Swift installation

positional arguments:
  {run-scenario,report-scenario}
    run-scenario        Run CRUD scenario, saving statistics. You must supply
                        *either* the -A, -U, and -K options, or the -S and -T
                        options.
    report-scenario     Generate a report from saved scenario statistics

optional arguments:
  -h, --help            show this help message and exit
  -v, --verbose         Enable more verbose output. (default: False)

The run-scenario sub-command of ssbench-master which actually runs a benchmark scenario:

$ ssbench-master run-scenario -h
usage: ssbench-master run-scenario [-h] -f SCENARIO_FILE [--qhost QHOST]
                                   [--qport QPORT] [-A AUTH_URL] [-U USER]
                                   [-K KEY] [-S STORAGE_URL] [-T TOKEN]
                                   [-c COUNT] [-u COUNT] [-o COUNT] [-q]
                                   [--profile] [--noop] [-s STATS_FILE] [-r]
                                   [--pctile PERCENTILE]

optional arguments:
  -h, --help            show this help message and exit
  -f SCENARIO_FILE, --scenario-file SCENARIO_FILE
  --qhost QHOST         beanstalkd host (default: localhost)
  --qport QPORT         beanstalkd port (default: 11300)
  -A AUTH_URL, --auth-url AUTH_URL
                        Auth URL for the Swift cluster under test. (default:
                        http://192.168.22.100/auth/v1.0)
  -U USER, --user USER  The X-Auth-User value to use for authentication.
                        (default: dev:admin)
  -K KEY, --key KEY     The X-Auth-Key value to use for authentication.
                        (default: admin)
  -S STORAGE_URL, --storage-url STORAGE_URL
                        A specific X-Storage-Url to use; mutually exclusive
                        with -A, -U, and -K; requires -T (default: None)
  -T TOKEN, --token TOKEN
                        A specific X-Storage-Token to use; mutually exclusive
                        with -A, -U, and -K; requires -S (default: None)
  -c COUNT, --container-count COUNT
                        Override the container count specified in the scenario
                        file. (default: value from scenario)
  -u COUNT, --user-count COUNT
                        Override the user count (concurrency) specified in the
                        scenario file. (default: value from scenario)
  -o COUNT, --op-count COUNT
                        Override the operation count specified in the scenario
                        file. (default: value from scenario)
  -q, --quiet           Suppress most output (including progress characters
                        during run). (default: False)
  --profile             Profile the main benchmark run. (default: False)
  --noop                Exercise benchmark infrastructure without talking to
                        cluster. (default: False)
  -s STATS_FILE, --stats-file STATS_FILE
                        File into which benchmarking statistics will be saved
                        (default: /tmp/ssbench-
                        results/<scenario_name>.<timestamp>.stat)
  -r, --no-default-report
                        Suppress the default immediate generation of a
                        benchmark report to STDOUT after saving stats-file
                        (default: False)
  --pctile PERCENTILE   Report on the N-th percentile, if generating a report.
                        (default: 95)

The report-scenario sub-command of ssbench-master which can report on a previously-run benchmark scenario:

$ ssbench-master report-scenario -h
usage: ssbench-master report-scenario [-h] -s STATS_FILE [-f REPORT_FILE]
                                      [--pctile PERCENTILE] [-r RPS_HISTOGRAM]

optional arguments:
  -h, --help            show this help message and exit
  -s STATS_FILE, --stats-file STATS_FILE
                        An existing stats file from a previous --run-scenario
                        invocation (default: None)
  -f REPORT_FILE, --report-file REPORT_FILE
                        The file to which the report should be written
                        (default: <open file '<stdout>', mode 'w' at
                        0x1002511e0>)
  --pctile PERCENTILE   Report on the N-th percentile. (default: 95)
  -r RPS_HISTOGRAM, --rps-histogram RPS_HISTOGRAM
                        Also write a CSV file with requests completed per
                        second histogram data (default: None)

Example Run

First make sure beanstalkd is running. Each greenthread in ssbench-worker used to have its own connection to beanstalkd which meant the maximum file descriptor limit for beanstalkd would probably need to be raised. However, now there is just one connection for ssbench-master and two connections per ssbench-worker process.:

$ beanstalkd -l 127.0.0.1 &

Then, start one or more ssbench-worker processes (each ssbench-worker process defaults to a maximum gevent-based concurrency of 256, but the -c option can override that default):

$ ssbench-worker 1 &
$ ssbench-worker 2 &

Finally, run one ssbench-master process which will manage and coordinate the benchmark run:

$ ssbench-master run-scenario -f scenarios/very_small.scenario -u 4 -c 100 -o 613 --pctile 90
INFO:root:Starting scenario run for "Small test scenario"
INFO:root:Ensuring 100 containers (ssbench_*) exist; concurrency=10...
INFO:root:Initializing cluster with stock data (up to 4 concurrent workers)
INFO:root:Starting benchmark run (up to 4 concurrent workers)
Benchmark Run:
  .  <  1s first-byte-latency
  o  <  3s first-byte-latency
  O  < 10s first-byte-latency
  * >= 10s first-byte-latency
  X    work job raised an exception
  _    no first-byte-latency available
...............................................................................
...............................................................................
...............................................................................
...............................................................................
...............................................................................
...............................................................................
...............................................................................
............................................................
INFO:root:Deleting population objects from cluster
INFO:root:Calculating statistics for 613 result items...

Small test scenario
Worker count:   1   Concurrency:   4  Ran 2013-02-17 01:20:00 UTC to 2013-02-17 01:20:14 UTC (13s)

% Ops    C   R   U   D       Size Range       Size Name
 91%   % 27  36  18  18        4 kB -  66 kB  tiny
  9%   % 27  36  18  18      100 kB - 200 kB  small
---------------------------------------------------------------------
         27  36  18  18      CRUD weighted average

TOTAL
       Count:   613  Average requests per second:  47.3
                            min       max      avg      std_dev  90%-ile                   Worst latency TX ID
       First-byte latency:  0.006 -   0.275    0.040  (  0.048)    0.105  (all obj sizes)  tx21f0a21d5b8743c481e8548210b3617d
       Last-byte  latency:  0.006 -   0.334    0.083  (  0.070)    0.190  (all obj sizes)  txf01ccd23344c4b94b26b24f7afbbb93d
       First-byte latency:  0.006 -   0.275    0.041  (  0.049)    0.107  (    tiny objs)  tx21f0a21d5b8743c481e8548210b3617d
       Last-byte  latency:  0.006 -   0.334    0.084  (  0.071)    0.196  (    tiny objs)  txf01ccd23344c4b94b26b24f7afbbb93d
       First-byte latency:  0.006 -   0.169    0.031  (  0.034)    0.051  (   small objs)  tx48b6768ca9894588b0bdb5e24dec51a2
       Last-byte  latency:  0.015 -   0.239    0.076  (  0.056)    0.169  (   small objs)  tx46463f2296d64fc9a16c541592c7b2ea

CREATE
       Count:   178  Average requests per second:  13.8
                            min       max      avg      std_dev  90%-ile                   Worst latency TX ID
       First-byte latency:  N/A   -   N/A      N/A    (  N/A  )    N/A    (all obj sizes)
       Last-byte  latency:  0.025 -   0.334    0.127  (  0.069)    0.227  (all obj sizes)  txf01ccd23344c4b94b26b24f7afbbb93d
       First-byte latency:  N/A   -   N/A      N/A    (  N/A  )    N/A    (    tiny objs)
       Last-byte  latency:  0.025 -   0.334    0.128  (  0.070)    0.231  (    tiny objs)  txf01ccd23344c4b94b26b24f7afbbb93d
       First-byte latency:  N/A   -   N/A      N/A    (  N/A  )    N/A    (   small objs)
       Last-byte  latency:  0.049 -   0.190    0.108  (  0.044)    0.180  (   small objs)  tx899c24b465a94db79edc08a516675570

READ
       Count:   207  Average requests per second:  16.1
                            min       max      avg      std_dev  90%-ile                   Worst latency TX ID
       First-byte latency:  0.006 -   0.059    0.018  (  0.010)    0.032  (all obj sizes)  tx1aaca8cc64c944088e87ee4a8046bd04
       Last-byte  latency:  0.006 -   0.086    0.025  (  0.014)    0.044  (all obj sizes)  tx9ed06a526c054ef9970828faa62bb60b
       First-byte latency:  0.006 -   0.059    0.018  (  0.010)    0.032  (    tiny objs)  tx1aaca8cc64c944088e87ee4a8046bd04
       Last-byte  latency:  0.006 -   0.066    0.023  (  0.012)    0.041  (    tiny objs)  tx9541abbe77fe4633b367912c5446957d
       First-byte latency:  0.006 -   0.035    0.016  (  0.008)    0.028  (   small objs)  tx2c0a585b9fda4a63be2ffaafe327fe8b
       Last-byte  latency:  0.015 -   0.086    0.040  (  0.017)    0.061  (   small objs)  tx9ed06a526c054ef9970828faa62bb60b

UPDATE
       Count:   123  Average requests per second:   9.5
                            min       max      avg      std_dev  90%-ile                   Worst latency TX ID
       First-byte latency:  N/A   -   N/A      N/A    (  N/A  )    N/A    (all obj sizes)
       Last-byte  latency:  0.039 -   0.259    0.119  (  0.062)    0.217  (all obj sizes)  txd0a4ed87775a4e7e980c0ca819da90ca
       First-byte latency:  N/A   -   N/A      N/A    (  N/A  )    N/A    (    tiny objs)
       Last-byte  latency:  0.039 -   0.259    0.117  (  0.062)    0.213  (    tiny objs)  txd0a4ed87775a4e7e980c0ca819da90ca
       First-byte latency:  N/A   -   N/A      N/A    (  N/A  )    N/A    (   small objs)
       Last-byte  latency:  0.072 -   0.239    0.134  (  0.063)    0.234  (   small objs)  tx46463f2296d64fc9a16c541592c7b2ea

DELETE
       Count:   105  Average requests per second:   8.1
                            min       max      avg      std_dev  90%-ile                   Worst latency TX ID
       First-byte latency:  0.020 -   0.275    0.083  (  0.062)    0.176  (all obj sizes)  tx21f0a21d5b8743c481e8548210b3617d
       Last-byte  latency:  0.020 -   0.276    0.083  (  0.062)    0.176  (all obj sizes)  tx21f0a21d5b8743c481e8548210b3617d
       First-byte latency:  0.020 -   0.275    0.085  (  0.063)    0.181  (    tiny objs)  tx21f0a21d5b8743c481e8548210b3617d
       Last-byte  latency:  0.020 -   0.276    0.085  (  0.063)    0.181  (    tiny objs)  tx21f0a21d5b8743c481e8548210b3617d
       First-byte latency:  0.030 -   0.169    0.065  (  0.044)    0.149  (   small objs)  tx48b6768ca9894588b0bdb5e24dec51a2
       Last-byte  latency:  0.030 -   0.169    0.065  (  0.044)    0.149  (   small objs)  tx48b6768ca9894588b0bdb5e24dec51a2

INFO:root:Scenario run results saved to /tmp/ssbench-results/Small_test_scenario.2013-02-16.171956.stat
INFO:root:You may generate a report with:
  ssbench-master report-scenario -s /tmp/ssbench-results/Small_test_scenario.2013-02-16.171956.stat

The No-op Mode

To test the maximum throughput of the ssbench-master ==> beantalkd ==> ssbench-worker infrastructure, you can add --noop to a ssbench-master run-scenario command and the scenario will be “run” but the ssbench-worker processes will not actually talk to the Swift cluster.

In this manner, you may determine your maximum requests per second if talking to the Swift cluster were free.

The reported “Average requests per second:” value in the “TOTAL” section of the report should be higher than you expect to get out of the Swift cluster itself. My 2012 15” Retina Macbook Pro can get ~2,700 requests per second with --noop using a local beanstalkd, one ssbench-worker, and a user count (concurrency) of 4.

Contributing to ssbench

First, please use the Github Issues for the project when submitting bug reports or feature requests.

Code submissions should be submitted as pull requests and all code should be PEP8 (v. 1.4.2) compliant. Current unit test line coverage is not 100%, but code contributions should not lower the code coverage (so please include new tests or update existing ones as part of your change).

If contributing code which implements a feature or fixes a bug, please ensure a Github Issue exists prior to submitting the pull request and reference the Issue number in your commit message.

When submitting your first pull request, please also update AUTHORS to include yourself, maintaining alphabetical ordering by last name.

If any of the file(s) you change do not yet have a copyright line with your name, please add one at the bottom of the others, above the license text (but never remove any existing copyright lines). Your copyright line should look something like:

# Copyright (c) 2013 FirstName LastName