Varnish memory usage

[Ken Brownfield]

>   966403669          .            .   SMA outstanding bytes

There's your 1GB cache buffer, which is what you're setting.  Obviously, Varnish needs memory to do other things, so you'll see a fixed couple of hundred extra megs.  Also, each thread (e.g., worker) will allocate its own memory, including a stack.  This memory usage will scale and contract as load spawns and reaps threads.  This is true of any server, especially examples such as Squid and MySQLd.

Linux (including 10.04) sets a default stack size of 8MB:

-s: stack size (kbytes)        8192

With 500 threads, you could in theory see up to 4GB of VIRT.

Run "pmap -x PID" on the child process (or grandchildren), and you will see where the memory goes.  It should reflect the above -- you'll see 500+ 8MB stacks, plus a lot of other 1MB allocations, which is the block size used by jemalloc IIRC.

If you really only want to use 1G, specify something like "malloc,800M".

Hope it helps,
-- 
Ken

On Jun 9, 2010, at 5:29 PM, Michael Lenaghan wrote:

> What a way to start! Obviously, I accidentally hit "send." Let's try
> this again...
> 
> I'm running Varnish 2.1 on Ubuntu 10.04. We ran a test to purposely
> fill Varnish's cache. We've defined that cache as "malloc,1G". After
> running our test, "top" shows:
> 
> 1486m VIRT memory
> 1.3g RES memory
> 81m SHR memory
> 
> Either I've mis-configured something or mis-understood something.
> Either way, help is appreciated.
> 
> In case it's of use the output of varnishstat follows.
> 
> 0+05:22:49                                               domU-12-31-38-00-9D-27
> Hitrate ratio:       10      100     1000
> Hitrate avg:     0.0381   0.0813   0.0705
> 
>        3889         0.00         0.20 Client connections accepted
>      227735         0.99        11.76 Client requests received
>       10916         0.00         0.56 Cache hits
>      215592         0.00        11.13 Cache misses
>      211160         0.00        10.90 Backend conn. success
>          12         0.00         0.00 Backend conn. failures
>        5646         0.99         0.29 Backend conn. reuses
>      211144         0.00        10.90 Backend conn. was closed
>      216791         0.99        11.19 Backend conn. recycles
>        4575         0.99         0.24 Fetch with Length
>      212231         0.00        10.96 Fetch chunked
>          31          .            .   N struct sess_mem
>           2          .            .   N struct sess
>      205011          .            .   N struct object
>      205014          .            .   N struct objectcore
>      205014          .            .   N struct objecthead
>           1          .            .   N struct vbe_conn
>         500          .            .   N worker threads
>         500         0.00         0.03 N worker threads created
>     1259710         0.00        65.04 N worker threads limited
>           2          .            .   N backends
>       10569          .            .   N expired objects
>        4425          .            .   N LRU moved objects
>      216589         0.99        11.18 Objects sent with write
>        3889         0.00         0.20 Total Sessions
>      227735         0.99        11.76 Total Requests
>        1226         0.99         0.06 Total pass
>      216806         0.99        11.19 Total fetch
>    97606086       221.79      5039.29 Total header bytes
>   833650072         2.97     43040.43 Total body bytes
>          13         0.00         0.00 Session Closed
>      231611         0.99        11.96 Session herd
>    21199614        59.41      1094.51 SHM records
>      697327         2.97        36.00 SHM writes
>          38         0.00         0.00 SHM MTX contention
>           8         0.00         0.00 SHM cycles through buffer
>      432162         0.99        22.31 SMA allocator requests
>      410022          .            .   SMA outstanding allocations
>   966403669          .            .   SMA outstanding bytes
> 27988956353          .            .   SMA bytes allocated
> 27022552684          .            .   SMA bytes free
>          13         0.00         0.00 SMS allocator requests
>        3670          .            .   SMS bytes allocated
>        3670          .            .   SMS bytes freed
>      216806         0.99        11.19 Backend requests made
>           1         0.00         0.00 N vcl total
>           1         0.00         0.00 N vcl available
>           1          .            .   N total active purges
>           1         0.00         0.00 N new purges added
>       19369         1.98         1.00 Client uptime
> 
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