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Re: [linux] Re: How to find out what/who started a certain process?

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  • J
    ... Yep... suspend is the S3 sleep state which is a low-power state that essentially shuts down all but the most critical components providing enough power to
    Message 1 of 15 , Aug 2, 2013
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      On Thu, Aug 1, 2013 at 11:08 PM, thad_floryan <thad@...> wrote:

      > HOWEVER, there is a VERY important consideration for those who use
      > laptops and want to hibernate or suspend: you'll need a swap space
      > larger than RAM because both RAM and a lot of context (e.g., which
      > programs, etc.) need to be saved there for a hibernate/suspend. I
      > don't use my laptops that way but many do and I'm sure there are some
      > guidelines that can be found by searching the 'Net. Here's what I
      > just searched for and it found what appears to be very good advice:
      >
      > how much swap space for linux to allow hibernate or suspend
      >
      > Hmmm, I may have erred using the term "suspend [to RAM]"; "sleep"
      > seems to be the situation using the swap area per glancing over the
      > précis of each hit from the above search.

      Yep... suspend is the S3 sleep state which is a low-power state that
      essentially shuts down all but the most critical components providing
      enough power to keep the RAM state and be able to revive the system on
      a pre-defined event like a lid-open or RTC alarm or button press.
      AFAIK, the disk is never touched when doing an S3 sleep unless the
      system just happened to be doing a write to disk when S3 was
      initiated, but swap shouldn't come into it.

      S4, or Hibernate, writes the contents of RAM and then some to disk, as
      Thad explained. My general recommendation for laptops is 1.5xRAM...
      so a 4GB laptop would be perfectly safe with a 6GB swap partition.
      But YMMV and Use Common Sense... becuase on an 8GB Laptop, you really
      don't need 12GB of Swap, unless you want it.

      My view on swap in general is that if you are at a point where you
      need swap, you need more RAM and you need to run less stuff (or you've
      got something with a nasty memory leak).

      That said, my server type machines all have 1GB swap files just to
      provide a little buffer, though it's never hit because I don't run
      them hard enough to need disk swapping of memory pages.
    • thad_floryan
      ... Right. I have a swap area setup more out of habit (over the years) than any perceived real need. I will regularly have 20 instances of Firefox up and
      Message 2 of 15 , Aug 3, 2013
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        --- In linux@yahoogroups.com, J <dreadpiratejeff@...> wrote:
        > [...]
        > My view on swap in general is that if you are at a point where you
        > need swap, you need more RAM and you need to run less stuff (or you've
        > got something with a nasty memory leak).
        >
        > That said, my server type machines all have 1GB swap files just to
        > provide a little buffer, though it's never hit because I don't run
        > them hard enough to need disk swapping of memory pages.

        Right. I have a swap area setup more out of habit (over the years) than
        any perceived real need. I will regularly have >20 instances of
        Firefox up and running (since I grab pages before they disappear on
        news sites) even on systems with only 4GB RAM and no problems at all;
        for the curious, I don't like tabbed browsing since it complicates
        how one backs up to the beginning, so clicking a URL while holding the
        shift key down brings up a new FF with the clicked-on URL page. It's
        fast and I see neither any inefficiencies nor swap usage.

        With a few exceptions, due to my budget most of my "new" computer
        purchases of the past 6 years have been refurbs which I quickly max
        out with RAM and HD, often upgrading the CPUs (AMD and Intel) to the
        "fastest" supported by the BIOS and motherboard, and replacing stock PSUs with newer "green" PSUs capable of higher power demands and they
        actually use less power thanks also to CPU scaling. For example, see
        this screenshot:

        http://thadlabs.com/PIX/CentOS_6.2_desktop.jpg 122kB

        noting both CPU monitors at the top are showing "1GHz" -- those scale
        up to 2.3GHz (and up to 2.6GHz on my second dc5850) when I really do
        some number crunching or compiling.

        Weirdest thing is the new PSUs must be doing something "funny" to the
        power lines because [up to a point] the more systems I power up the
        less electrical power is being charged that day (I have a Time-of-Use
        SmartMeter). I generally average 15-18kW/day usage (except on laundry
        days) and when running 4-5 computers more than usual the billable
        usage will drop to around 14kW -- I have no explanation for this and
        I'm not complaining as it must be some phasing interactions since the
        incoming power is 3-phase 240VAC which is split to single-phase 120VAC
        for all circuits except the stove, main oven, and clothes dryer which
        operate on 240VAC. Here's the power meter:

        http://thadlabs.com/PIX/Thad_TOU_power_meter.jpg 148kB

        Thad
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