Possible working method to get actual process size on Linux

[Per Liden]

On 10/3/19 2:47 PM, Stefan Reich wrote:
> The situation is still confusing. My process has:
> 
> Runtime.totalMemory() = 2.7 GB

This is the current Java heap capacity (some of it may be free/available 
for new allocations).

> Runtime.usedMemory() =~ 1 GB

There is no Runtime.usedMemory(), so I don't know where this number 
comes from.

> 
> ps_mem.py says:
> 
> root at smartbot:~/bin# ps_mem.py -p 4837
>   Private  +   Shared  =  RAM used Program
> 
> 745.5 MiB +   2.4 GiB =   3.1 GiB java
> ---------------------------------
>                            3.1 GiB

This is the total process size, i.e. Java heap, jitted code, VM data 
structures, etc.

> 
> Is the heap counted as shared memory here? The shared memory value seems 
> way too large.

Yes, the ZGC heap is mapped as shared memory.

/Per

> 
> My own tool reports < 1 GB as RSS which seems way too low...
> 
> 
> On Thu, 3 Oct 2019 at 14:32, Per Liden <per.liden at oracle.com 
> <mailto:per.liden at oracle.com>> wrote:
> 
> 
>     On 10/3/19 2:23 PM, Stefan Reich wrote:
>      > Hi Per!
>      >
>      > Yes, I saw, sorry for not responding the other time.
>      >
>      > This problem is, /proc/*/smaps_rollup doesn't exist on one of my
>      > machines (the one with the oldest kernel). On the newer machines,
>     yeah,
>      > it may be an option to use PSS from smaps_rollup.
>      >
>      > Not sure if there are any tools which would help here.
> 
>     I know some of them (e.g. ps_mem.py), works on older kernels that
>     doesn't have /proc/<pid>/smaps_rollup.
> 
>     cheers,
>     Per
> 
>      >
>      > Greetings,
>      > Stefan
>      >
>      > On Thu, 3 Oct 2019 at 14:16, Per Liden <per.liden at oracle.com
>     <mailto:per.liden at oracle.com>
>      > <mailto:per.liden at oracle.com <mailto:per.liden at oracle.com>>> wrote:
>      >
>      >
>      >     Did you see my reply to your previous question on this topic?
>     Tools to
>      >     extract this data (PSS) exist. Are they not doing what you want?
>      >
>      >     cheers,
>      >     Per
>      >
>      >
>      >
>      > --
>      > Stefan Reich
>      > BotCompany.de // Java-based operating systems
> 
> 
> 
> -- 
> Stefan Reich
> BotCompany.de // Java-based operating systems