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    <p>I believe there is no good reason to make your process wake up if it has nothing to do. Simply set the timeout to when you first <em>need</em> to do something. For example, if your server has a semantic of disconnecting a client after N seconds of inactivity, set the epoll timeout to the time after the first client would have to be disconnected assuming no activity. In other words, set it to:</p> <p>min{expire_time(client); for each client} - current_time</p> <p>Or, if that's negative, you can disconnect at least one client immediately. In general, this works not only for disconnecting clients; you can abstract the above into "software timers" within your application.</p> <p>I'm failing to see this compromise you've mentioned. If you use a timeout any smaller than you have to, you'll wake up before you <em>have</em> to, then, presumably, go back to sleep because you have nothing to do. What good does that do? On the other hand, you <em>must not</em> use a timeout any larger than what you have to - because that would make your program not respect the disconnect timeout policy.</p> <p>If your program is not waiting for any time-based event (like disconnecting clients), just give epoll_wait() timeout value -1, making it wait forever.</p> <p><strong>UPDATE</strong> If you're worried that this process being given less CPU when other processes are active, just give it lower nice value (scheduler priority). On the other hand, if you're worried that your server process will be swapped out to disk in favour of other processes when it's idle, it is possible to <a href="https://unix.stackexchange.com/questions/10214/per-process-swapiness-for-linux">avoid swapping it out</a>. (or you can just lower /proc/sys/vm/swappiness, affecting all processes)</p>
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    1. POepoll performance for smaller timeout values
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    1. USAmbroz Bizjak
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    1. COUnless the disconnect policy is not a hard one. One could even argue that it is sufficient to disconnect dead clients if other clients are contacting the server -- no need to free resources that are unused anyway.
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      1. USSimon Richter
    2. COThanks Amborz/Simon, my question is that if I give too small timeout value, will this hurt the performance in anyway.. like more cpu utilization etc
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    3. COYes, waking up will utilize CPU, obviously, and if you wake up to do nothing, this CPU time will be wasted. How much CPU will be wasted depends on how often you wake up. Shouldn't be too hard to test in practice.
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