[indiana-discuss] [perf-discuss] Memory leak somewhere, maybe in libc (libc_hwcap2.so.1 / SXCE b105 x64) ?

[Martin Bochnig]

Hi!

On Thu, Feb 12, 2009 at 4:05 AM, Bob Friesenhahn
<bfriesen at simple.dallas.tx.us> wrote:

> Your 'top' program obviously has some sort of bug but otherwise I don't see
> anything necessarily out of the ordinary in the top listings.


Does this explain why a wget process grew to 2.2GB (where I killed it) ??
Then wget must have exactly the same bug, which is unlikely. Therefore
the bug must be in a shared lib which both use. This suggests (but is
not limited to) libc.


> Some releases
> of top work much better under Solaris than others.  Top is a very handy tool
> but neither 'SIZE' or 'RES' is indicative of a problem.  For example 'SIZE'
> is increased by simply memory mapping a file or device since it is based on
> the number of allocated virtual memory pages.  Virtual memory pages may be
> shared between processes.  RES is a bit more useful since it indicates the
> amount of those virtual memory pages which are mapped into RAM, but it is
> also misleading since pages may remain mapped into RAM due to lack of
> pressure for memory (from other processes) as well as pressure from memory
> from the running process.

Yes. But I also checked with a csw-version of top.
I decided, however, to attach screenshots depicting the version of top
which ships as part of SXCE, as reference (because it has probably
been ARC-reviewed and co-checked a 100 times).

> If you want to learn more about how memory is
> being used by a Solaris process, then see 'pmap'.

Okay, let me read its man page. But first, here is its current output
for one of the still running wget processes:

# pmap 11017
11017:	wget -m -p -k www.opensolaris.org
11017:	wget -m -p -k www.opensolaris.org
08045000      12K rw---    [ stack ]
08050000     208K r-x--  /usr/bin/wget
08093000      20K rwx--  /usr/bin/wget
08098000  553652K rwx--    [ heap ]
FEB10000      64K rwx--    [ anon ]
FEB23000       4K rwxs-    [ anon ]
FEB30000      24K rwx--    [ anon ]
FEB40000    1276K r-x--  /usr/lib/libc/libc_hwcap2.so.1
FEC8F000      32K rwx--  /usr/lib/libc/libc_hwcap2.so.1
FEC97000       8K rwx--  /usr/lib/libc/libc_hwcap2.so.1
FECA0000       4K rwx--    [ anon ]
FECB0000    1276K r-x--  /lib/libcrypto.so.0.9.8
FEDFF000      88K rw---  /lib/libcrypto.so.0.9.8
FEE15000      12K rw---  /lib/libcrypto.so.0.9.8
FEE20000     264K r-x--  /lib/libssl.so.0.9.8
FEE72000      16K rw---  /lib/libssl.so.0.9.8
FEE80000     624K r-x--  /lib/libnsl.so.1
FEF2C000      24K rw---  /lib/libnsl.so.1
FEF32000      20K rw---  /lib/libnsl.so.1
FEF40000      56K r-x--  /lib/libsocket.so.1
FEF5E000       4K rw---  /lib/libsocket.so.1
FEF70000       4K rwx--    [ anon ]
FEF80000       4K r-x--  /lib/libdl.so.1
FEF90000       4K r-x--  /lib/libmd5.so.1
FEFA0000       4K r-x--  /lib/libintl.so.1
FEFB0000       4K rwx--    [ anon ]
FEFBD000     184K r-x--  /lib/ld.so.1
FEFFB000       8K rwx--  /lib/ld.so.1
FEFFD000       4K rwx--  /lib/ld.so.1
 total    557904K
#

So, as you can see it has 545MB on Heap.
> It does seem a bit unusual that any swap is used at all.  Double check to
> make sure that you have not copied a bunch of large files to /tmp since /tmp
> comes out of the total memory/swap budget.

Sure, thanks.
But of course I don't use /tmp for storing big files anymore (as this
box has 2.4 TB of ZFS storage). And also no big file got stored there
by FireFox's download manager or stuff like that.

Proof:

bash-3.2$ du -h /tmp
  12K	/tmp/.removable
   4K	/tmp/hsperfdata_root
   4K	/tmp/.X11-unix
   4K	/tmp/.X11-pipe
  36K	/tmp/hsperfdata_noaccess
  28K	/tmp/plugtmp-1
   4K	/tmp/.ICE-unix
   4K	/tmp/fam-martin
   4K	/tmp/x
   8K	/tmp/plugtmp
   4K	/tmp/hsperfdata_martin
   4K	/tmp/65535_sun_studio_12
   4K	/tmp/plugtmp-2
   8K	/tmp/plugtmp-3
   8K	/tmp/.vbox-martin-ipc
   8K	/tmp/plugtmp-4
  31M	/tmp
bash-3.2$

> Perhaps the algorithm that 'wget' uses requires a lot of memory to keep
> track of things, or perhaps the version you are using has a memory leak.
>
> Bob


I use the default versions shipping with SXCE (/usr/bin/top and
/usr/sfw/bin/wget)

Both my version of wget shall have a bug and my version of top?
Seriously, how likely is this?
Isn't it more likely that there is a problem in a shared library that
both happen to use?

%martin