tree: 7bbdb470f0ec255652027c8d06f7937cb49d39fc [path history] [tgz]
  1. BUILD.gn
  2. OWNERS
  3. README.md
  4. action.h
  5. data/
  6. loadbench.cc
  7. measurement.h
  8. meta/
  9. object.h
  10. random.h
  11. tracing.cc
  12. tracing.h
  13. tracing_unittest.cc
  14. utility.cc
  15. utility.h
  16. worker.h
  17. workload.cc
  18. workload.h
  19. workload_unittest.cc
src/testing/loadbench/README.md

Loadbench: Configurable Workload Simulator

Introduction

Loadbench is a tool for stressing the system in interesting ways to validate performance, latency, and stability under load. It provides a simple JSON-based configuration language to describe workload behavior, including interactions with kernel objects, synchronization primitives, and timing.

The tool is intended to support the following use cases:

  • Manually testing kernel and system behavior, in conjunction with tracing, to observe and validate correctness and performance under directed stress.
  • Providing a framework for automated load metrics and stress testing.
  • Supporting development of a suite of regression tests to capture minimal reproduction cases of issues found in real world applications.

General Usage

The loadbench package is not included in any standard product build. To use the tool for local manual testing, add the following to your fx set command:

$ fx set <other args> --with-base //src/testing:testing

Once the tool is included in a build and flashed to the device, it can be driven from the commandline using the run command:

$ fx shell run loadbench --help

Use the --file <path> option to specify a JSON workload specification file to execute:

$ fx scp ./my_test_load.json "[$(fx get-device-addr)]:/tmp/"
$ fx shell run loadbench --file /tmp/my_test_load.json

Note: /tmp/r/sys/fuchsia.com:loadbench:0#meta:loadbench.cmx will not be present until the loadbench package is run for the first time after device boot. To explicitly create this directory from the commandline use:

$ fx shell mkdir -p /tmp/r/sys/fuchsia.com:loadbench:0\#meta:loadbench.cmx/

Workload specification files can also be built into the package. This is useful for workloads intended for automated and regression testing. These files can be run manually by referencing them relative to the /pkg/data/ path prefix:

$ fx shell run loadbench --file /pkg/data/simple_load.json

Workload Specification Files

Workload specification files are standard JSON format, with extensions to allow trailing commas and single // ... and multi-line /* ... */ comments.

The primary document element of a specification file is always a JSON object:

{
  // Top-level specification members ...
}

Top-Level Specification Members

The primary document element may contain any of the following members.

name - Workload Name (optional)

The name member is an optional string to print when running the workload. The value of this member must be a string.

Example:

{
  "name": "Example workload name string."
  // ...
}

config - Workload Config Options (optional)

The config member is an optional JSON object that may contain the following options:

  • priority: Integer specifying the priority to set the main control thread to before kicking off the worker threads. This may be used to prevent high priority workers from delaying the main control thread.
  • interval: Specifies the duration to run the benchmark. See duration spec for permitted values and formats.

Example:

{
  "config": {
    "priority": 25,
    "interval": "30s",
  }
  // ...
}

intervals - Named Intervals (optional)

The intervals member is an optional JSON object that specifies named intervals that worker threads may specify as parameters to time-based actions. The key of each member of this object specifies the interval's name, while the value is an object that specifies its duration.

The duration object may have one of the following key/value pairs:

  • duration: Specifies the numeric duration of the interval.
  • uniform: A JSON object that specifies the min and max durations to select from a random uniform distribution.

See duration spec for permitted values and formats.

Example:

{
  "intervals": {
    "fast inverval": { "duration": "250us" },
    "short random interval": { "uniform": { "min": "1ms", "max": "5ms" } },
    "long random interval": { "uniform": { "min": "10s", "max": "20s" } },
  },
  // ...
}

objects - Global Objects (optional)

The objects member is an optional JSON object that specifies named objects that worker threads may interact with. The key of each member of this object specifies the object‘s name, while the value is a JSON object that specifies the object’s type and parameters.

Example:

{
  "objects": {
    "main timer": { "type": "timer" },
    "port a": { "type": "port" },
    "port b": { "type": "port" },
  },
  // ...
}

The following types are currently supported:

  • channel: Zircon channel object.
  • event: Zircon event object.
  • port: Zircon port object.
  • timer: Zircon timer object.

Other object types and parameters will be introduced over time.

behaviors - Global Behaviors (optional)

The behaviors member is an optional JSON object that specifies named behaviors that may be referenced by worker threads. Named behaviors make it easier to add a common action or set of actions to workers without verbose repetition in each worker spec.

The key of each member of this object specifies the behavior's name, while the value may either be a JSON action spec or an array of JSON action specs. See action spec for more details on actions.

Example:

{
  "behaviors": {
    "spinner": { "action": "spin", "duration": "10m" },
    "half load": [
      { "action": "spin", "duration": "5ms" },
      { "action": "sleep", "duration": "5ms" },
    ]
  },
  // ...
}

workers - Worker Specification

The workers member is an array of JSON objects that specify the number, behavior, and grouping parameters of worker threads making up the workload.

Each array element is a JSON object representing one or more worker threads. A worker spec may have the following members:

name - Worker Name (optional)

The name member is an optional string value to associate with each worker spawned by the containing worker spec. The name is printed in statistics output and also used as a secondary grouping key in aggregate statistics calculations.

group - Worker Group (optional)

The group member is an optional string value that is used to group worker threads during aggregate statistics calculations. The group name is the primary grouping key.

instances - Worker Instances (optional)

The instances member is an optinal integer specifying the number of workers to spawn from the containing worker spec.

The default value is 1.

priority - Worker Priority (optional)

The priority member is an optional integer or JSON object that specifies the fair priority or the deadline parameters, respectively, of the workers spawned from the containing worker spec.

How the value is interpreted depends on whether it is an integer or a JSON object. When the value is an integer, it is interpreted as a fair priority and the workers are bound to a fair priority profile. When the value is a JSON object, it is interpreted as a deadline parameter set and must contain the string keys “capacity”, “deadline”, and “period”. The values of these keys are durations representing the corresponding deadline parameters. The workers are bound to a deadline profile with the given parameters.

Example:

// Worker spec with fair priority.
{
  "priority": 24,
  // ...
}

// Worker spec with deadline priority.
{
  "priority": { "capacity": "2ms", "deadline": "10ms", "period": "10ms" },
  // ...
}
actions - Worker Actions

The actions member is an array of JSON objects that describe the sequence of actions for the worker to perform. In general, actions are performed in the order specified in the array. When the last action is reached, the worker loops back to the first action and the sequence is repeated.

The sequence of actions is performed either until the overall workload interval expires or until an early exit action is executed.

See action spec for more details on actions.

Example:

{
  // ...
  "workers": [
    // First worker spec defining a group of 8 identical workers.
    {
      "instances": 8,
      "group": "High Priority",
      "name": "CPU Bound",
      "priority": 24,
      "actions": [
        { "action": "spin", "duration": "10m" },
      ]
    },
    // Second worker spec defining a group of 8 identical workers with different
    // behavior.
    {
      "instances": 8,
      "group": "High Priority",
      "name": "Bursty",
      "priority": 24,
      "actions": [
        { "action": "spin", "uniform": { "min": "1ms", "max": "10ms"} },
        { "action": "sleep", "uniform": { "min": "100ms", "max": "1s"} },
      ]
    },
    // Third worker spec defining a group of 8 identical workers with different
    // priority from the first.
    {
      "instances": 8,
      "group": "Low Priority",
      "name": "CPU Bound",
      "priority": 12,
      "actions": [
        { "action": "spin", "duration": "10m" },
      ]
    },
    // Fourth worker spec defining a group of 8 identical workers with different
    // priority from the second.
    {
      "instances": 8,
      "group": "Low Priority",
      "name": "Bursty",
      "priority": 12,
      "actions": [
        { "action": "spin", "uniform": { "min": "1ms", "max": "10ms"} },
        { "action": "sleep", "uniform": { "min": "100ms", "max": "1s"} },
      ]
    }
  ],
  // ...
}

tracing - Kernel Tracing Specification (optional)

The tracing member is an optional member that provides configuration parameters for running kernel tracing on the workload. Tracing defaults to off whenever this member is not present.

group mask - Kernel Tracing Group Mask (optional)

The group mask member may be an unsigned int or a string. It specifies the group mask to set up kernel tracing with. If this member is missing, the group mask defaults to KTRACE_GRP_ALL.

The following groups are supported:

  • KTRACE_GRP_ALL: 0xFFF
  • KTRACE_GRP_META: 0x001
  • KTRACE_GRP_LIFECYCLE: 0x002
  • KTRACE_GRP_SCHEDULER: 0x004
  • KTRACE_GRP_TASKS: 0x008
  • KTRACE_GRP_IPC: 0x010
  • KTRACE_GRP_IRQ: 0x020
  • KTRACE_GRP_PROBE: 0x040
  • KTRACE_GRP_ARCH: 0x080
  • KTRACE_GRP_SYSCALL: 0x100
filepath - Human Readable Kernel Tracing Translation Filepath (optional)

The filepath member is a string that indicates where a human readable translation of the read kernel traces should be saved. If this member is missing, no human readable translation is generated.

The loadbench package has permission to write to /tmp inside its own namespace. If accessing from the shell, this directory will be located at

/tmp/r/sys/fuchsia.com:loadbench:0#meta:loadbench.cmx
string ref - Kernel Trace String Reference (optional)

The string ref member is a string that indicates a string ref to look for when generating trace stats. If this member is missing, no kernel trace stats are generated. Similarly, if the provided string ref is not found in the string ref table or no events are found that match it, no trace stats are generated.

Example:

"tracing": {
  "group mask": "KTRACE_GRP_ALL",
  "filepath": "/tmp/latest.ktrace",
  "string ref": "clock_read",
},

Duration Spec

Various objects have duration perameters, incuding intervals, time-based actions, and deadline profiles. A duration value may either be an integer or a string containing an integer scalar value and a unit suffix.

When the duration value is an integer, it is taken in units of nanoseconds.

String values must include one of the following units:

  • Hours: “h”
  • Minutes: “m”
  • Seconds: “s”
  • Milliseconds: “ms”
  • Microseconds: “us”
  • Nanoseconds: “ns”

Example:


{ "action": "spin", "duration": 1000 } // Spin for 1000ns or 1us. { "action": "sleep", "uniform": { "min": "1s", "max": "10s" } } // Sleep for between 1 and 10 s. { "priority": { "capacity": "1ms", "deadline": "10ms", "period": "20ms" } }

Action Spec

Actions are JSON objects that describe a discrete action for a worker to execute. All actions have an action member with a string value specifying the type of action. Actions may require additional members to specify relevant parameters, such as intervals, objects, and even other actions.

The following actions are supported:

spin - Spin for an Interval

The spin action causes the worker to enter a spin loop for the given interval. The interval may either be a simple duration or a uniform distribution.

Example:

{ "action": "spin", "duration": "2m" }

{ "action": "spin", "uniform": { "min": "1ms", "max": "3ms" } }

duration

When the spin action contains a duration member, the spin will continue for the constant value given as a duration spec.

uniform

When the spin action contains a uniform member, the spin will continue for the duration selected from a uniform distrubution. The value must be a JSON object string keys for the min and max duration specs defining the uniform range.

sleep - Sleep for an Interval

The sleep action causes the worker to sleep for the given interval. This action supports the same parameters as the spin action.

write - Write to a Channel

The write action causes the worker to write a message with the given number of bytes to the given named channnel object.

channel

The channel member specifies the string name of the channel object to write to.

Example:

{ "action": "write", "channel": "main channel", "side": 0, "bytes": 1024 }

side

The side member specifies which side of the channel object to write to. The value must be an integer with either the value 0 or 1.

bytes

The bytes member specifies how many bytes to write in the message.

read - Read from a Channel

The read action is similar to the write action, except that the given number of bytes is read from the channel instead of written.

behavior - Execute a Named Behavior

The behavior action causes the worker to execute the given named behavior from the top-level behavior member.

Example:

{ "action": "behavior", "name": "spin action" }

name

The name member specifies the string name of the behavior to execute.

wait_async - Async Wait on an Object

The wait_async action causes the worker to perform zx_object_wait_async on the given port and object.

Example:

{ "action": "wait_async", "port": "port name", "object": "object name", "signals": 8 }

port

The port member specifies the string name of the port object to register with.

object

The object member specifies the string name of the object to register with the port.

signals

The signals member specifies the integer signal mask of events to wait for.

wait_one - Wait on an Object

The wait_one action causes the worker to perform zx_object_wait_one on the given object.

Example:

{ "action": "wait_one", "object": "object name", "signals": 8, "deadline": "5s" }

object

The object member specifies the string name of the object to wait on.

signals

The signals member specifies the integer signal mask of events to wait for.

deadline (optional)

The deadline member optionally specifies the timeout duration of the wait operation.

port_wait - Wait on a Port

The port_wait action causes the worker to perform zx_port_wait on the given port object.

Example:

{ "action": "port_wait", "port": "port name", "deadline": "5s" }

port

The port member specifies the string name of the port object to wait on.

deadline (optional)

The deadline member optionally specifies the timeout duration of the wait operation.

signal - Signal an Object

The signal action causes the worker to perform zx_object_signal on the given object.

Example:

{ "action": "signal", "object": "object name", "clear": 0, "set": 8 }

object

The object member specifies the string name of the object to signal.

clear

The clear member specifies the integer mask of the events to clear.

set

The set member specifies the integer mask of the events to set.

timer_set - Set a Timer Object

The timer_set object sets the given timer to the given relative deadline and optional slack.

Example:

{ "action": "timer_set", "timer": "timer name", "deadline": "100ms", "slack": "250us" }

timer

The timer member specifies the string name of the timer object to set.

deadline

The deadline member specifies the deadline of the timeout, relative to the current time, as a duration.

slack

The slack member specifies the timer slack as a duration.

exit - Exit the Action Loop Early

The exit action causes the worker to exit the action loop and idle until the end of the workload run.

Example:

{ "action": "exit" }