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On Sat, May 3, 2014 at 10:16 AM, Chris Stankevitz <chrisstankevitz@×××××.com |
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> wrote: |
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> Hello, |
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> |
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> I have a small system: |
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> |
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> - 6GB drive |
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> |
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> - ext4 partition mounted readonly |
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> |
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> - swap partition that is not listed in fstab and not enabled. (I will |
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> swapon it every few weeks or so if I need it for a large compile job) |
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> |
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> - 2 GB RAM |
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> |
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> When the system boots it processing video from a USB camera. The |
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> program dynamically allocates and releases memory while it runs, but |
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> stores no data in memory or on disk (read-only). The memory usage |
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> does not grow over time. |
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> |
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> When things are going well, top looks like so: |
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> |
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> === |
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> |
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> Tasks: 68 total, 1 running, 67 sleeping, 0 stopped, 0 zombie |
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> %Cpu0 : 88.3 us, 11.7 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, |
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> 0.0 st |
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> %Cpu1 : 25.5 us, 2.3 sy, 0.0 ni, 72.1 id, 0.0 wa, 0.0 hi, 0.0 si, |
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> 0.0 st |
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> %Cpu2 : 6.0 us, 0.7 sy, 0.0 ni, 93.3 id, 0.0 wa, 0.0 hi, 0.0 si, |
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> 0.0 st |
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> %Cpu3 : 25.7 us, 2.3 sy, 0.0 ni, 72.0 id, 0.0 wa, 0.0 hi, 0.0 si, |
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> 0.0 st |
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> KiB Mem: 1861644 total, 161648 used, 1699996 free, 6948 buffers |
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> KiB Swap: 0 total, 0 used, 0 free, 57728 cached |
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> |
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> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND |
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> 2129 root 20 0 1774440 81712 25388 S 160.0 4.4 25:55.46 obt |
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> 705 root 20 0 0 0 0 S 1.0 0.0 0:07.87 kswapd0 |
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> 2049 ueyed 20 0 620472 14092 13652 S 1.0 0.8 0:09.34 |
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> ueyeusbd |
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> |
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> |
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> ==== |
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> |
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> |
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> Q1: Why does the kswapd0 process from time to time take up 100% CPU? |
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> |
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> Q2: Why does top show "cached swap" eventhough I do not have swap mounted? |
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> |
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> Q3: Is there anything I can do to prevent kswapd0 from using CPU on my |
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> system? e.g. disable SWAP in the kernel config |
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> |
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> I suspect the answer to Q1 is: |
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> |
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> a) kernel is not configured properly for my hardware |
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> or |
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> b) there is some bad side effect to my readonly root fs |
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> |
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> Thank you, |
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> |
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> Chris |
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> |
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> |
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