Date: Thu, 6 Sep 2007 14:59:38 -0700 From: Alfred Perlstein <alfred@freebsd.org> To: net@freebsd.org Subject: take II: Allocating AF constants for vendors. Message-ID: <20070906215938.GL87451@elvis.mu.org>
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* Alfred Perlstein <alfred@freebsd.org> [070821 14:13] wrote: > Hello all, > > I would like to reserve about 64 entries for VENDOR specific address > families in sys/socket.h. > > I think this will allow vendors to comfortably use the array of > address families without worrying about overlap with FreeBSD > protocols. > > If no one objects I plan to commit this in the next few days. > > The format will be along the lines of: > > AF_VENDOR0 -> AF_VENDOR63 > > Suggestions? Sam asked that I provide some numbers for this proposal, I have them, however in the meanwhile another proposal I've floated was implementing a reservation system where FreeBSD would allocate every even number in the AF_ set of constants and leave the odd numbers for vendors. Q: "What if a vendor wants to then contribute code to FreeBSD?" A: They should have asked FreeBSD to reserve a number, now they can allocate a FreeBSD one. The numbers are specifically meant for internal address families. Here's the numbers for simply bumping AF_MAX: Here's what I have for sizing it up 59 entries. =========================================================================== GDB commands to get sizes of structures related to AF_MAX: printf "AF_MAX: %d\n", sizeof(((struct ifnet *)0)->if_afdata) / sizeof(void*) printf "struct netexport: %d\n", sizeof(struct netexport) printf "struct ifnet: %d\n", sizeof(struct ifnet) printf "route.c:rt_tables: %d\n", sizeof(rt_tables) =========================================================================== Data from AF_MAX = 37 (FreeBSD-stable) AF_MAX: 37 Kernel size: /usr/src/sys/i386/compile/JUNIPER_6_2_SMP % size kernel.debugSMALLMAX text data bss dec hex filename 5964450 791752 367916 7124118 6cb496 kernel.debugSMALLMAX /usr/src/sys/i386/compile/JUNIPER_6_2_SMP % gdb kernel.debugSMALLMAX GNU gdb 6.1.1 [FreeBSD] Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-marcel-freebsd"... (gdb) printf "AF_MAX: %d\n", sizeof(((struct ifnet *)0)->if_afdata) / sizeof(void*) AF_MAX: 37 (gdb) printf "struct netexport: %d\n", sizeof(struct netexport) struct netexport: 316 (gdb) printf "struct ifnet: %d\n", sizeof(struct ifnet) struct ifnet: 644 (gdb) printf "route.c:rt_tables: %d\n", sizeof(rt_tables) route.c:rt_tables: 152 (gdb) =========================================================================== Data from AF_MAX = 96 (FreeBSD-stable + 59 entries) AF_MAX: 96 /usr/src/sys/i386/compile/JUNIPER_6_2_SMP % size kernel.debug text data bss dec hex filename 5964450 791752 368140 7124342 6cb576 kernel.debug .(14:22:56)(alfred@pants.juniper.net) !!! SANDBOX UNSET!!! /usr/src/sys/i386/compile/JUNIPER_6_2_SMP % gdb kernel.debug GNU gdb 6.1.1 [FreeBSD] Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-marcel-freebsd"... (gdb) printf "AF_MAX: %d\n", sizeof(((struct ifnet *)0)->if_afdata) / sizeof(void*) AF_MAX: 96 (gdb) printf "struct netexport: %d\n", sizeof(struct netexport) struct netexport: 552 (gdb) printf "struct ifnet: %d\n", sizeof(struct ifnet) struct ifnet: 880 (gdb) printf "route.c:rt_tables: %d\n", sizeof(rt_tables) route.c:rt_tables: 388 (gdb) % =========================================================================== Summary of differences: size: text data bss dec hex filename 5964450 791752 367916 7124118 6cb496 kernel.debugSMALLMAX 5964450 791752 368140 7124342 6cb576 kernel.debug AF_MAX: 37 struct netexport: 316 struct ifnet: 644 route.c:rt_tables: 152 AF_MAX: 96 struct netexport: 552 struct ifnet: 880 route.c:rt_tables: 388 bss diff: bytes: 224 percent: 1% dec diff: bytes: 224 percent: 1% AF_MAX: difference: 59 percent: 62% struct netexport: bytes: 236 percent: 43% struct ifnet: bytes: 236 percent: 27% route.c:rt_tables: bytes: 236 percent: 61% =========================================================================== Unknown: (I don't know how to get a static variable from gdb) unknown: netatm/atm_if.c: -> atm_ifouttbl =========================================================================== Source inpection reveals the following iterations over AF_MAX: vfs_free_addrlist: iterates whenever a filesystem exports are changed. net/if.c: when deleting an interface, the rt_tables are walked to delete all routes. =========================================================================== Misc information: Both PF_MAX and NET_MAXID are influenced by AF_MAX, but they do not appear to influence the size of anything in the kernel. =========================================================================== Summary: bss diff: bytes: 224 percent: 1% dec diff: bytes: 224 percent: 1% AF_MAX: difference: 59 percent: 62% struct netexport: bytes: 236 percent: 43% struct ifnet: bytes: 236 percent: 27% route.c:rt_tables: bytes: 236 percent: 61% -- - Alfred Perlstein
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