On 7/09/2012 8:49 p.m., Daniel Beschorner wrote:
On 7/09/2012 2:54 a.m., Daniel Beschorner wrote:
The shared memory cache is harder to follow in its memory use than in 3.1,
am I right that the "cached" value of the "free" output is somehow related
due to shared mem?
Where are you spotting this?
I'm trying to get the feel of tuning/monitoring the cache_mem parameter in 3.2 
SMP.
Little real mem used, don't know exactly where to look right.

config: linux 64bit, workers 2, no disk cache, 3GB shared mem cache:

Cache information for squid:
        Hits as % of all requests:      5min: 11.3%, 60min: 13.0%
        Hits as % of bytes sent:        5min: 2.1%, 60min: 1.4%
        Memory hits as % of hit requests:       5min: 55.3%, 60min: 52.8%
        Disk hits as % of hit requests: 5min: 25.2%, 60min: 12.7% (?without 
disk cache?)
        Storage Swap size:      0 KB
        Storage Swap capacity:   0.0% used,  0.0% free
        Storage Mem size:       2997120 KB

3GB cache_mem ^^^

        Storage Mem capacity:   95.3% used,  4.7% free
        Mean Object Size:       0.00 KB
        Requests given to unlinkd:      0
Resource usage for squid:
        UP Time:        63270.597 seconds
        CPU Time:       2165.255 seconds
        CPU Usage:      3.42%
        CPU Usage, 5 minute avg:        12.62%
        CPU Usage, 60 minute avg:       11.93%
        Process Data Segment Size via sbrk(): 117432 KB
        Maximum Resident Size: 6111728 KB
        Page faults with physical i/o: 0
Memory usage for squid via mallinfo():
        Total space in arena:  117696 KB
        Ordinary blocks:       105553 KB   3734 blks
        Small blocks:               0 KB      0 blks
        Holding blocks:          2816 KB      8 blks
        Free Small blocks:          0 KB
        Free Ordinary blocks:   12143 KB
        Total in use:           12143 KB 10%
        Total free:             12143 KB 10%
        Total size:            120512 KB
Memory accounted for:
        Total accounted:        61336 KB  51%

61MB accounted for by MemPools feature in Squid. This is most of the memory used by Squid, but not everything, and does seem to omit the 3GB of shared memory cache.

        memPool accounted:      61336 KB  51%
        memPool unaccounted:    59176 KB  49%

59MB in that omitted group. Counted by mallinfo() but not by Squid MemPools.

Total of about 100MB other memory. Its not clear from here whether that is across al processes, or for just one. But ...

        memPoolAlloc calls: 495209534
        memPoolFree calls:  497771963
Internal Data Structures:
          5509 StoreEntries
          5509 StoreEntries with MemObjects
         93660 Hot Object Cache Items
             0 on-disk objects


free output: (only 300M "normal" mem used? but also only 1,4GB in "cached", if 
shared mem is accounted there?)

              total       used       free     shared    buffers     cached
Mem:       3926544    1841484    2085060          0     103584    1434028
-/+ buffers/cache:     303872    3622672
Swap:      2095100          0    2095100


top output:

   PID USER      PR  NI  VIRT  RES  SHR S   %CPU %MEM    TIME+  COMMAND
  8118 nobody    20   0 3167m 724m 676m S      7 18.9  18:02.57 squid
  8119 nobody    20   0 3189m 783m 713m S      5 20.4  18:44.31 squid

3.2GB of virtual memory used by each process. That would be 3GB memory cache and ~100MB of other memory use by each Squid process.

Amos

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