Subject: re: improving ssh performance on sun4m systems
To: None <email@example.com>
From: Brian A. Seklecki <firstname.lastname@example.org>
Date: 03/09/2002 22:45:55
On Sat, 9 Mar 2002, Todd Vierling wrote:
> On Sun, 10 Mar 2002, matthew green wrote:
> : [note: -mcpu=v8 means the resulting code will not run on sparc v7 and
> : older systems.]
> : this isn't true; we emulate these instructions in the kernel.
> However, it's ungodly slow, since the emulation makes the already slow
> sun4's and sun4c's have to do even more work.
> : /etc/ld.so.conf work needs to be done for sparc.
> Yes. I've already said precisely what needs to be done in the past to make
> this less grotty, and it's pretty simple, but I simply don't have the
In the mean time are these details sufficient enough to compose a chapter
for "The NetBSD Guide" on optimizing for different ports (at least i386,
sparc, etc. where there are CPUs of different steppings) ?
> machinery in easy reach to test it on the varying architectures:
> * A flag indicating presence of v8 instructions needs to be in the machdep
> sysctl tree. I don't know if there is one there already capable of being
> used in ld.so.conf.
> * Given the above, a small `libc_v8.so', in the vein of `libm387.so' for
> i386, can be created that simply contains the v8 instruction replacements
> for the libcalls:
> .mul .umul .div .udiv .rem .urem
> * ld.so.conf can be shipped by default with a libc override, such as:
> libc.so.12 machdep.v8_present 1:libc_v8.so.0,libc.so.12
> With all of the above, you gain *nearly* all the speed all around for v8
> instructions on sun4m and sun4u-32 architectures (modulo the overhead of
> layering libc_v8 on libc), without hosing speed for the same binaries on v7
> -- Todd Vierling <email@example.com> * Wasabi & NetBSD: Run with it.
> -- CDs, Integration, Embedding, Support -- http://www.wasabisystems.com/
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