src/devices/tests/ddk-schedule-work/schedule-work.test.fidl

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.device.schedule.work.test;

using zx;

/// Buckets are arranged as following:
/// [0] => [0ns, 100ns]
/// [1] => [100ns, 250ns]
/// [2] => [250ns, 500ns]
/// [3] => [500ns, 1us]
/// [4] => [1us, 2us]
/// [5] => [2us, 4us]
/// [6] => [4us, 7us]
/// [7] => [7us, 15us]
/// [8] => [15us, 30us]
/// [9] => [30us, infinity]
struct LatencyHistogram {
    array<uint64>:10 buckets;
};

protocol TestDevice {
    /// Schedules work. |batch_size| refers to how many work_items to keep
    /// outstanding at any given time, while |num_work_items| refers to total
    /// number of work items.
    ScheduleWork(uint32 batch_size, uint32 num_work_items) -> () error zx.status;

    /// Spawns a thread which schedules work.
    ScheduleWorkDifferentThread() -> () error zx.status;

    /// Triggers once all outstanding work is complete.
    GetDoneEvent() -> (handle<event> event) error zx.status;

    /// Returns whether how many work items ran since last time it was invoked.
    ScheduledWorkRan() -> (uint32 work_items_run, LatencyHistogram histogram);

    /// Spawns an thread with a dedicated async loop.
    GetChannel(request<OwnedChannelDevice> test) -> () error zx.status;
};

// This is only necessary because it is currently not possible to
// asynchronously reply to a fidl message.
protocol OwnedChannelDevice {
    /// Schedules work and blocks until it completes. |batch_size| refers to how
    /// many work_items to keep outstanding at any given time, while
    /// |num_work_items| refers to total number of work items.
    ScheduleWork(uint32 batch_size, uint32 num_work_items)
        -> (LatencyHistogram histogram) error zx.status;
};