zircon/system/fidl/fuchsia-kernel/kernel-counter.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.kernel;

using fuchsia.mem;
using zx;

/// Protocol for retrieving kcounter information.
[Discoverable, Layout = "Simple"]
protocol Counter {
    /// Retrives a VMO containining summarized kcounter data. The vmo returned
    /// in |buffer| is in "inspect-vmo" format, documented elsewhere.
    GetInspectVMO() -> (zx.status status, fuchsia.mem.Buffer buffer);

    /// Request that the previously-returned VMO buffer's data be updated. The
    /// data may not be updated if it was already recently updated (updates are
    /// limited to an unspecified rate, but approximately every few seconds).
    UpdateInspectVMO() -> (zx.status status);
};