CpuIdleMetric.cpp

/*
* If not stated otherwise in this file or this component's LICENSE file the
* following copyright and licenses apply:
*
* Copyright 2023 Sky UK
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#ifdef ENABLE_CPU_IDLE_METRICS

#include "CpuIdleMetric.h"
#include "Log.h"
#include "Procrank.h"
#include <sys/prctl.h>


CpuIdleMetric::CpuIdleMetric(std::shared_ptr<JsonReportGenerator> reportGenerator) :
        mReportGenerator(std::move(reportGenerator)),
        mIdleMetrics({})
{

}


void CpuIdleMetric::StartCollection([[maybe_unused]] const std::chrono::seconds frequency)
{
    // Check if collectd is running in the background. If it is, it might interfere with the stat collection since
    // the idle metrics are globally scoped
    LOG_INFO("Starting CPU idle metric collection");

    Procrank procrank;
    auto runningProcesses = procrank.GetMemoryUsage();

    auto collectRunning = std::any_of(runningProcesses.begin(), runningProcesses.end(),
                                      [](const Procrank::ProcessMemoryUsage &proc)
                                      {
                                          return proc.process.name().find("collectd") != std::string::npos;
                                      });

    if (collectRunning) {
        LOG_WARN("*** WARNING:: Collectd is running in the background. This may cause incorrect CPU idle readings ***");
    }

    // Start by resetting the stats
    auto ret = prctl(PR_GET_IDLE_METRICS, &mIdleMetrics, IDLE_METRICS_VERSION_V2, 0, 0);
    if (ret != 0) {
        LOG_ERROR("Failed to reset idle stats with error %d (%s)", ret, strerror(errno));
    }

    // Nothing to do now until we stop collection
}

void CpuIdleMetric::StopCollection()
{
    // Get the latest stats
    LOG_INFO("Stopping CPU idle metric collection");
    auto ret = prctl(PR_GET_IDLE_METRICS, &mIdleMetrics, IDLE_METRICS_VERSION_V2, 0, 0);
    if (ret != 0)
    {
        LOG_ERROR("Failed to get idle stats with error %d (%s)", ret, strerror(errno));
    }
}

void CpuIdleMetric::SaveResults()
{
    mReportGenerator->addCpuIdleMetrics(mIdleMetrics);
}

#endif