Messages in this thread | | | Date | Sat, 20 Apr 2002 17:06:09 -0700 | From | Dan Kegel <> | Subject | Saving RAM on an all-RAM system by compressing executables? |
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I'm working with an all-RAM system (where a host processor pokes the linux kernel and initial ramdisk into RAM, then releases the reset line). The kernel is 2.4.17 or so. I have only 64 MB (or 32 or 16, depending), so every megabyte is precious. The C++ app I'm running on this system is 5MB, kinda fat. I'd like to save a couple megabytes somehow, either by compressing the executable, or by using execute-in-place.
I made a cramfs image of the app; that shrunk it from 5MB down to 2MB. You can't mount cramfs images from tmpfs, so I made a little ramfs, and loopback mounted it from there, then measured ram usage on a 64MB system with the app both running and not running.
/bin/free reported (kb): in tmpfs, not running: 47888 in tmpfs, running: 47244 in cramfs, not running:46972 in cramfs, running: 46336
Looks like I lose! Using cramfs to compress the app appears to *waste* a megabyte over just using the noncompressed app.
From what I can tell, there's no support for execute-in-place except on MIPS with a hacked gcc.
OK, I've exhausted my stock of clever ideas; does anyone have a suggestion about how to save RAM in my situation? (gzexe won't do it, nor will upx, as they all create a temporary uncompressed file on execution...)
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