[mythtv-users] mythbackend still eats memory: the current status

Udo van den Heuvel udovdh at xs4all.nl
Thu May 21 11:57:45 UTC 2009


David Lister wrote:
 > (...)

Thanks for the explanation!

> If there was a real leak (i.e. memory allocation without free), the
> lowest BASE of the VSZ would be rising steeply in a linear manner.
> Especially noticeable on sbrk trim drops.

Did you try to graph the numbers I posted when this thread was revived 
most recently? See at the bottom of this message.

> As you can see on [2], during the whole 6 months, there was NO rise
> whatsoever. The bottom line is at 330k the whole time, i.e. no leak.
> 
> Graph [1] - is that one process without interruption? If so, then again,
> no leak - perhaps there's the slightest 1k rise towards the end, but
> that's just too little for too short a time to call it a leak. If you
> mean the big sawtooth, it's properly freed to the OS eventually, that is
> not what you call a leak. If the graph begins with mythbackend startup,
> this peak could even be associated with some initial data collection,
> (custom?) allocator trim kicking in for the first time after initial
> estimations, or whatever - it's irrelevant, because it's freed.

My idea is: the process starts, acquires memory and acquires some more 
as it progresses with doing what it does.
In a process like mythbackend, after a certain time I expect the memory 
consumption to 'level out', i.e.: not grow any furter. All buffers 
necessary have been mallocced, all variables were filled and freed etc.
Please explain if this general idea is wrong and/or where it needs 
correction.
If the general idea is true, then the numbers I collected look strange 
since they would lead to the assumption that if this would continue the 
computer would grind to a halt eventually.


Kind regards,
Udo


%CPU %MEM    VSZ   RSS TTY      STAT START   TIME
11.0  8.7 407028 85280 ?        Ssl  03:06  12:59
10.9 11.6 445264 113104 ?       Ssl  May06 170:32
10.8 14.4 474364 140528 ?       Ssl  May06 325:50
10.8 15.4 482604 149604 ?       Ssl  May06 483:36
10.7 16.3 492400 158516 ?       Ssl  May06 632:38
10.6 17.3 501680 168732 ?       Ssl  May06 781:28
10.7 18.8 515120 182808 ?       Ssl  May06 940:08
10.8 20.7 534032 201016 ?       Ssl  May06 1105:05
10.8 22.0 546336 213748 ?       Ssl  May06 1266:19
10.9 23.3 559368 226224 ?       Ssl  May06 1429:23
10.9 24.9 575364 242112 ?       Ssl  May06 1591:37
10.9 25.7 575424 250272 ?       Ssl  May06 1742:04
10.8 25.7 592900 250248 ?       Ssl  May06 1895:01
10.9 26.8 605720 260412 ?       Ssl  May06 2058:53
10.9 27.2 618236 264712 ?       Ssl  May06 2224:00
10.9 27.4 630772 266556 ?       Ssl  May06 2386:19


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