Understanding my Processor RRD?


  • Banned

    I'm trying to find what my average % CPU utilization is on my box.

    On my dashboard the CPU usage is usually 5-8% when I'm looking at it. The 15 minute load averages I've seen anywhere from ~ .04 to .25, but usually around ~.1.

    When I look at my RRD under Processors if I add the averages of everything but processes (as I understand that's simply the number of processes running) then it comes out to 1.6%
    For the last month: 1.48%
    Last hour: 1.38%

    So these values are pretty consistent, but very different from what I see in CPU utilization.
    If I bring the granularity down to 1 minute in the last 8 hours, it shows Maximum usage of 49.43%.

    The only two things I can think of are that I am not reading my RRD's right and I can't get average CPU usage by adding the averages of user+nice+system utils+interrupts (don't think interrupts should b added but did so anyways since it's so small).

    Or, running the WebGUI where I can see the Dashboard CPU monitoring dramatically increases CPU load, but the massive majority of a time no one is accessing the WebGUI so loads are really way lower.

    Still, I don't see how my i5-2400 is averaging <2% CPU. I only have  home 50/5 connection, but LAN runs over a VPN @ AES-256 & there is a VPN server (not often used) that connects clients at AES-128 and then sends traffic out through the AES-256 VPN. Also running pfBlockerNG.

    i5-2400 does have AES-NI and is obviously overpowered, and my connection is not fast. But I still expected more of a CPU usage than <2%.

    Anyone have any input on this, why it's so slow or what I'm doing wrong?



  • @pfBasic:

    I'm trying to find what my average % CPU utilization is on my box.

    On my dashboard the CPU usage is usually 5-8% when I'm looking at it. The 15 minute load averages I've seen anywhere from ~ .04 to .25, but usually around ~.1.

    When I look at my RRD under Processors if I add the averages of everything but processes (as I understand that's simply the number of processes running) then it comes out to 1.6%
    For the last month: 1.48%
    Last hour: 1.38%

    So these values are pretty consistent, but very different from what I see in CPU utilization.
    If I bring the granularity down to 1 minute in the last 8 hours, it shows Maximum usage of 49.43%.

    The only two things I can think of are that I am not reading my RRD's right and I can't get average CPU usage by adding the averages of user+nice+system utils+interrupts (don't think interrupts should b added but did so anyways since it's so small).

    That's just it, you're getting the average CPU usage. The 49% peak wont affect the average much unless it sustained for an extended period.

    Or, running the WebGUI where I can see the Dashboard CPU monitoring dramatically increases CPU load, but the massive majority of a time no one is accessing the WebGUI so loads are really way lower.

    Still, I don't see how my i5-2400 is averaging <2% CPU. I only have  home 50/5 connection, but LAN runs over a VPN @ AES-256 & there is a VPN server (not often used) that connects clients at AES-128 and then sends traffic out through the AES-256 VPN. Also running pfBlockerNG.

    i5-2400 does have AES-NI and is obviously overpowered, and my connection is not fast. But I still expected more of a CPU usage than <2%.

    Anyone have any input on this, why it's so slow or what I'm doing wrong?

    That ~2% seems about right to me. You'll probably never hit over 40k packets per second with 50Mbps and I don't think it should stress the CPU too much. Moreover, you'll probably max out your download bandwidth only occasionally (?) and those peaks won't affect the average that much.


  • Banned

    Well good to know, thank you!

    For anyone that's interested. With my setup running as previously described:

    i5-2400
    some HDD, I think a WD Blue 500+GB?
    intel PRO/1000 dual NIC

    Consumes about 40W on average with not enough fluctuation to mention.

    $0.12/kWh: $42/yr (US avg)
    $0.25/kWh: $88/yr (in-betweener)
    $0.37/kWh: $130/yr (HI avg)

    To put that in contrast, an SG-1000 runs at 2.5W idle, so if for simplicity we say it runs an average of 4W in use…. it's using about 10% of the power of my dusty old PC build.
    My build would cost you about $100-130 to buy if you don't have anything sitting around, vs the SG-1000 at $150 (includes support I think).
    Granted, the SG-1000 does not have even a fraction of the horsepower and probably wouldn't serve even my very modest VPN uses. But it's still a good bracket for real world cost to operate vs a dusty old PC.

    Ultimately, long term it will certainly pay to buy or put something together that will serve your needs for hopefully many years while remaining low power.

    Once I can justify it I'll probably switch to a newer low power fanless pentium or celeron or maybe even an atom if it's at a cheap enough price/perf point, combined with an i340 or 350 and a SATA DOM.

    I'd like to get down to about 15W without paying a ton up front and retaining some processing power.


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