Very Computer

by **Raj Sistl** » Sat, 23 Mar 2002 09:39:12

My executable links to a shared object (.so). When I run multiple copies of
the executable, the memory footprint of each instance reflects that an
instance of the shared object is getting loaded in to memory for each
executable instance.

Is this normal? I was expecting shared objects to behave like DLLs - code
segment if not replicated in RAM across multiple instances of the calling
executable.

Any suggestions?

Thanks much
Raj

by **Jimmy Zhan** » Sat, 23 Mar 2002 17:55:46

You might be looking at the virtual memory, the real physical content could
be
mapped to different processes. So it might be appear to you that way.

>My executable links to a shared object (.so). When I run multiple copies of
>the executable, the memory footprint of each instance reflects that an
>instance of the shared object is getting loaded in to memory for each
>executable instance.

>Is this normal? I was expecting shared objects to behave like DLLs - code
>segment if not replicated in RAM across multiple instances of the calling
>executable.

>Any suggestions?

>Thanks much
>Raj

by **Raj Sistl** » Sun, 24 Mar 2002 07:12:20

Well, I viewed the memory usage using "cat /proc/meminfo" and found that the
"MemFree" was decreasing by an equal amount with each successive instance of
the process.

Isn't MemFree the amount of free memory available?

Thanks
Raj

> You might be looking at the virtual memory, the real physical content
could
> be
> mapped to different processes. So it might be appear to you that way.

> >My executable links to a shared object (.so). When I run multiple copies
of
> >the executable, the memory footprint of each instance reflects that an
> >instance of the shared object is getting loaded in to memory for each
> >executable instance.

> >Is this normal? I was expecting shared objects to behave like DLLs - code
> >segment if not replicated in RAM across multiple instances of the calling
> >executable.

> >Any suggestions?

> >Thanks much
> >Raj

by **Jimmy Zhan** » Mon, 25 Mar 2002 18:59:08

Hmm...

Someone corrects me if I am wrong here.
.so could be static shared lib, the linker does the address patching, in
this
case no mem sharing takes place.

Or, .so is dynamic shared lib, the *loader* does the address patching, you
can expect mem sharing in this case.

Check the compiling flags to figure out if the lib is staticly or dynamicly
shared.

>Well, I viewed the memory usage using "cat /proc/meminfo" and found that
the
>"MemFree" was decreasing by an equal amount with each successive instance
of
>the process.

>Isn't MemFree the amount of free memory available?

>Thanks
>Raj

>> You might be looking at the virtual memory, the real physical content
>could
>> be
>> mapped to different processes. So it might be appear to you that way.

>> >My executable links to a shared object (.so). When I run multiple copies
>of
>> >the executable, the memory footprint of each instance reflects that an
>> >instance of the shared object is getting loaded in to memory for each
>> >executable instance.

>> >Is this normal? I was expecting shared objects to behave like DLLs -
code
>> >segment if not replicated in RAM across multiple instances of the
calling
>> >executable.

>> >Any suggestions?

>> >Thanks much
>> >Raj

Very Computer

Shared Library Issue

Shared Library Issue

Shared Library Issue

Shared Library Issue

Shared Library Issue