Subject: Re: difference in key calculations for ssh
To: Andrew Gillham <gillhaa@ghost.whirlpool.com>
From: Grey Wolf <greywolf@siteROCK.com>
List: current-users
Date: 05/25/2000 13:59:57
On Thu, 25 May 2000, Andrew Gillham wrote:

# Grey Wolf writes:
# > Why is it that a SPARCstation takes so much longer to calculate keys
# > in ssh than does an i386?
# 
# My guess would be for the same reasons rc5des is significantly faster
# on Intel.  My understanding is that the Intel is much faster at certain
# instructions (shifts?) that are heavily used by the encryption code.
# 
# > My ss5/170 takes disproportionately longer to calculate keys and
# > challenges and stuff for ssh than the PII/300 next to it -- the
# > SS5/170 takes about 30 seconds to respond with a password prompt, while
# > the PII/300 responds fairly instantaneously.
# 
# I am not seeing anything on the order of 30 times slower.
# time ssh <remote box> /usr/bin/true
# p133 (1.4.2) -> sparc2 (1.3.3, 50mhz no L2cache): 
# 0.899u 0.059s 0:08.71 10.7%     0+0k 8+4io 0pf+0w
# 
# p133 (1.4.2) -> p133 (1.4.2)
# 0.915u 0.039s 0:02.35 40.0%     0+0k 0+1io 0pf+0w

p450 (1.4Y) -> ultra 1 (Solaris 2.5)
0.165u 0.310s 0:06.59 7.1%	0+0k 0+0io 0pf+0w

p450 (1.4Y) -> p500 (Linux 2.2.12)
0.177u 0.305s 0:00.78 60.2%	0+0k 0+0io 0pf+0w

p450 (1.4Y) -> localhost
0.174u 0.307s 0:00.98 47.9%	0+0k 0+0io 0pf+0w

ss5/170 (1.4Y) -> localhost
10.603u 0.070s 0:32.82 32.5%    0+0k 0+1io 2pf+0w

WTF?!?

# So comparing the processor speeds, lack of L2 cache on the sparc, I am
# not all that surprised by the numbers.
# Your numbers though, sound horrible.  My sparc2 (50mhz) is kicking your
# SS5/170's butt. :-)
# 
# Try comparing the following on the machines:
# time ssh localhost /usr/bin/true
# 
# sparc: 4.843u 0.080s 0:12.63 38.9%     0+0k 0+5io 13pf+0w
# i386 : 0.899u 0.058s 0:02.49 37.7%     0+0k 0+8io 0pf+0w
# 
# So, about 5 times slower.  Let's see, 2.66 times slower clock speed, then
# some factor for no L2 cache, and a possibly faster set of instructions on
# the Intel.  Hmm, not totally out of line I guess.
# 
# 
# -Andrew
# -- 
# -----------------------------------------------------------------
# Andrew Gillham                            | NetBSD ist Affengeil.
# gillham@whirlpool.com                     | Nachts ist es kaelter
# I speak for myself, not for my employer.  | als draussen.
# 


				--*greywolf;

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