Subject: Re: procfs/kernfs "required"? [was Re: kernel & libkvm... ]
To: None <Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU, greywolf@captech.com>
From: James Graham - Systems Anarchist <greywolf@defender.VAS.viewlogic.com>
List: current-users
Date: 01/15/1996 14:53:50
#define AUTHOR "Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU (Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU)"

/*

[my size comparison deleted for brevity.  Summary:  procfs "isn't" that big.

 *
 * I don't believe you.  What architecture are you talking about?

This is a SS1+.

 * 
 * on the i386, various procfs files size to:
 * 
 * 12 [sun-lamp] GENERIC % size procfs_*
 * text    data    bss     dec     hex
 * 904     312     0       1216    4c0     procfs_ctl.o
 * 232     0       0       232     e8      procfs_fpregs.o
 * 564     0       0       564     234     procfs_mem.o
 * 60      0       0       60      3c      procfs_note.o
 * 228     0       0       228     e4      procfs_regs.o
 * 924     0       0       924     39c     procfs_status.o
 * 964     0       8       972     3cc     procfs_subr.o
 * 488     52      0       540     21c     procfs_vfsops.o
 * 3076    500     0       3576    df8     procfs_vnops.o
 * 13 [sun-lamp] GENERIC % size ../SUN_LAMP/procfs_*
 * text    data    bss     dec     hex
 * 232     0       0       232     e8      ../SUN_LAMP/procfs_fpregs.o
 * 564     0       0       564     234     ../SUN_LAMP/procfs_mem.o
 * 228     0       0       228     e4      ../SUN_LAMP/procfs_regs.o
 * 
 * the latter set are the 'standard' ones that are used by ptrace (which
 * in a perfect world would live elsewhere and be named differently, but
 * there's history there).
 * 
 * on a different architecture (sparc?) the numbers will be different
 * (and on sparc, i'd expect them to be larger).

I was looking at overall size usage; undoubtedly the procfs parts will
sum up to greater than the whole thing.  They must reference some common
structures or something...

 * Don't forget that, since kernel text is typically rounded to the page
 * size, extra space in the kernel used by the addition of procfs may be
 * 'hidden' because it was previously wasted...  but you're then that
 * much closer to using another page...

...and then there's that, too.  Even considering that, on a
SPARCstation, a "page" is 1k, it's still not that far off.

Thanks for your patience in explaining all this, though.  I can think
of some parties who would have lost their patience with me *LONG* ago!

 * 
 */

#undef AUTHOR	/* "Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU (Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU)" */




				--*greywolf;
--
"This is Betsy; go ahead, Heavens..."