Re: [libmicrohttpd] libmicrohttpd binary size?

[Christian Grothoff]

On 02/22/2012 07:13 PM, Glenn wrote:
> I've been getting familiar with libmicrohttpd and the more more I understand 
> it, the more I like it. One thing I haven't been able to figure out, though, is 
> why the binaries I've been able to build are so large.
>
> Executing './configure --disable-https --disable-messages 
> --disable-postprocessor --disable-dauth', then 'make' (CFLAGS=-Os 
> -fomit-frame-pointer in my environment) and finally 'sudo make install' results 
> in sizes of 152226 and 122697 for libmicrohttpd.a and libmicrohttpd.so.10.14.0, 
> respectively. (Linux Ubuntu 11.10, Intel i686 32 bit, gcc 4.5.4). --Not exactly 
> the 32k that is advertised.
>
> Can someone provide a pointer to where this has already been discussed? If not, 
> then maybe someone can answer directly: Why are my libmicrohttpd binaries so 
> big?

Hmm. I just tried your command (please make sure CFLAGS is in your 
environment *before* running configure; I suspect that might be part of 
your problem) and on my system (gcc 4.6.2) I then get:

$ ls -al *.14.0
-rwxr-xr-x 1 grothoff grothoff 50897 Feb 23 14:08 libmicrohttpd.so.10.14.0

Now, you can further reduce the size by stripping the binary:

$ strip libmicrohttpd.so.10.14.0

After that, I get:

$ ls -al *.14.0
-rwxr-xr-x 1 grothoff grothoff 41296 Feb 23 14:08 libmicrohttpd.so.10.14.0


Now, this is on AMD64 -- and the instruction set plays some role in how 
big the binary is.  If you only care about size on disk, you could also 
gzip it:

$ gzip *.14.0

$ ls -al *.gz
-rwxr-xr-x 1 grothoff grothoff 18922 Feb 23 14:08 
libmicrohttpd.so.10.14.0.gz


Now, if I do the same on ARM, I get:

# ls -al
-rwxr-xr-x 1 root root 41093 2012-02-23 07:17 libmicrohttpd.so.10.14.0
# strip libmicrohttpd.so.10.14.0
# ls -al
libmicrohttpd.so.10.14.0
-rwxr-xr-x 1 root root 30724 2012-02-23 07:17 libmicrohttpd.so.10.14.0

This is where our "32k" claim comes from (as IMO ARM is what matters for 
embedded devices, not Intel).  Again, if you compress, you can get a bit 
more:

# gzip *.14.0
-rwxr-xr-x 1 root root 16729 2012-02-23 07:17 libmicrohttpd.so.10.14.0.gz



Ultimately, on really small devices, none of these numbers are entirely 
meaningful as you also need to consider which functions from libc/POSIX 
you need for TCP/IP support, etc.  Some revisions ago we eliminated use 
of 'sscanf' in MHD to allow a more "minimal" version of libc to suffice 
for MHD.

IIRC some members on this list run MHD on systems with as little as 128K 
code space, so in such cases libc size does matter a lot.  See also
https://gnunet.org/bugs/view.php?id=1688


Happy hacking!

Christian