/// <summary>
/// Do the actual work in processing a task in the queue
/// </summary>
/// <param name="job"></param>
/// <param name="cpuPercentage"></param>
/// <returns></returns>
private void ProcessJob(IProcessJob job, int cpuPercentage)
{
// If we can't process, we'll discard this job, and pick it
// up again in future during the next GetPendingJobs call.
if (job.CanProcess)
{
string jobName = job.GetType().Name;
SetStatus($"{job.Name}", JobStatus.Running, cpuPercentage);
Logging.LogVerbose($"Processing job type: {jobName}");
Stopwatch stopwatch = new Stopwatch($"ProcessJob{jobName}");
try
{
job.Process();
}
catch (Exception ex)
{
Logging.LogError($"Exception processing {job.Description}: {ex.Message}");
}
finally
{
stopwatch.Stop();
}
// Now, decide how much we need to sleep, in order to throttle CPU to the desired percentage
// E.g., if the job took 2.5s to execute, then in order to maintain 25% CPU usage, we need to
// sleep for 7.5s. Similarly, if the job took 0.5s, and we want to maintain 75% CPU usage,
// we'd sleep for 0.33s.
double sleepFactor = (1.0 / (cpuPercentage / 100.0)) - 1;
if (sleepFactor > 0)
{
// Never ever sleep for more than 10s. Otherwise a long-running job that takes a minute
// to complete could end up freezing the worker thread for 3 minutes, which makes no
// sense whatsoeever. :)
const int maxWaitTime = 10 * 1000;
int waitTime = Math.Min((int)(sleepFactor * stopwatch.ElapsedTime), maxWaitTime);
Logging.LogVerbose($"Job '{jobName}' took {stopwatch.ElapsedTime}ms, so sleeping {waitTime} to give {cpuPercentage}% CPU usage.");
Thread.Sleep(waitTime);
}
}
}
