Re: scp performance degredation [ssh v3.4p1->3.7.1p2]

From: stor__sten (stor__sten_at_hotmail.com)
Date: 04/22/04 

Date: Thu, 22 Apr 2004 13:57:08 GMT

dtucker@dodgy.net.au (Darren Tucker) wrote in
news:c67mk1$nf0$1@gate.dodgy.net.au:

> Compare "scp -vvv" output between old and new versions and see if
> there's anything different.
>
> Start taking things out of the equation. Start with a single host and
> do scp you scp test.
>
> Then take scp out and test just ssh throughput, eg
> $ dd if=/dev/zero of=/tmp/file bs=1k count=128k
> $ time ssh localhost "cat /tmp/file" >/tmp/file2
>
> Then take file IO out:
> $ time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
>
> Hopefully these tests will single out something for a closer look.
>

As promised, here's the results of the testing...
---------------------
:/usr/platform/sun4u/sbin/prtdiag
System Configuration: Sun Microsystems sun4u 8-slot Sun Enterprise
E4500/E5500
System clock frequency: 100 MHz
Memory size: 16384Mb

========================= CPUs =========================

                    Run Ecache CPU CPU
Brd CPU Module MHz MB Impl. Mask
--- --- ------- ----- ------ ------ ----
 0 0 0 400 8.0 US-II 10.0
 0 1 1 400 8.0 US-II 10.0
 2 4 0 400 8.0 US-II 10.0
 2 5 1 400 8.0 US-II 10.0
 4 8 0 400 8.0 US-II 10.0
 4 9 1 400 8.0 US-II 10.0
 6 12 0 400 8.0 US-II 10.0
 6 13 1 400 8.0 US-II 10.0

========================= Memory =========================

                                              Intrlv. Intrlv.
Brd Bank MB Status Condition Speed Factor With
--- ----- ---- ------- ---------- ----- ------- -------
 0 0 2048 Active OK 60ns 8-way A
 0 1 2048 Active OK 60ns 8-way A
 2 0 2048 Active OK 60ns 8-way A
 2 1 2048 Active OK 60ns 8-way A
 4 0 2048 Active OK 60ns 8-way A
 4 1 2048 Active OK 60ns 8-way A
 6 0 2048 Active OK 60ns 8-way A
 6 1 2048 Active OK 60ns 8-way A
------------------
:ssh -vvv 127.0.0.1
OpenSSH_3.4p1, SSH protocols 1.5/2.0, OpenSSL 0x0090603f
debug1: Reading configuration data /usr/local/etc/ssh_config
debug1: /usr/local/etc/ssh_config line 25: Deprecated option
"FallBackToRsh"
debug1: /usr/local/etc/ssh_config line 26: Deprecated option "UseRsh"
debug3: cipher ok: blowfish-cbc [blowfish-cbc,aes128-cbc,3des-
cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: cipher ok: aes128-cbc [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: cipher ok: 3des-cbc [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: cipher ok: cast128-cbc [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: cipher ok: arcfour [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: cipher ok: aes192-cbc [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: cipher ok: aes256-cbc [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug3: ciphers ok: [blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc]
debug1: Rhosts Authentication disabled, originating port will not be
trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to 127.0.0.1 [127.0.0.1] port 22.
debug1: Connection established.
debug1: identity file /opt/home/user/.ssh/identity type 0
debug1: identity file /opt/home/user/.ssh/id_rsa type -1
debug3: Not a RSA1 key file /opt/home/user/.ssh/id_dsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: no key found
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: no key found
debug1: identity file /opt/home/user/.ssh/id_dsa type 2
debug1: Remote protocol version 2.0, remote software version OpenSSH_
3.4p1
debug1: match: OpenSSH_3.4p1 pat OpenSSH*
Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.4p1
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-
hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: blowfish-cbc,aes128-cbc,3des-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-
hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: server->client blowfish-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: client->server blowfish-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 122/256
debug1: bits set: 1575/3191
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /opt/home/user/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug1: Host '127.0.0.1' is known and matches the DSA host key.
debug1: Found key in /opt/home/user/.ssh/known_hosts:2
debug1: bits set: 1572/3191
debug1: ssh_dss_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT
debug1: authentications that can continue: publickey,password,keyboard-
interactive
debug3: start over, passed a different list publickey,password,keyboard-
interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: next auth method to try is publickey
debug1: try privkey: /opt/home/user/.ssh/id_rsa
debug3: no such identity: /opt/home/user/.ssh/id_rsa
debug1: try pubkey: /opt/home/user/.ssh/id_dsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: input_userauth_pk_ok: pkalg ssh-dss blen 433 lastkey 10bdb0 hint
2
debug2: input_userauth_pk_ok: fp
87:79:73:a6:af:97:1d:80:27:d8:34:b1:23:75:ba:96
debug3: sign_and_send_pubkey
debug1: read PEM private key done: type DSA
debug1: ssh-userauth2 successful: method publickey
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug1: send channel open 0
debug1: Entering interactive session.
debug2: callback start
debug1: ssh_session2_setup: id 0
debug1: channel request 0: pty-req
debug3: tty_make_modes: ospeed 38400
debug3: tty_make_modes: ispeed 38400
debug3: tty_make_modes: 1 3
debug3: tty_make_modes: 2 28
debug3: tty_make_modes: 3 127
debug3: tty_make_modes: 4 21
debug3: tty_make_modes: 5 4
debug3: tty_make_modes: 6 0
debug3: tty_make_modes: 7 0
debug3: tty_make_modes: 8 17
debug3: tty_make_modes: 9 19
debug3: tty_make_modes: 10 26
debug3: tty_make_modes: 11 25
debug3: tty_make_modes: 12 18
debug3: tty_make_modes: 13 23
debug3: tty_make_modes: 14 22
debug3: tty_make_modes: 16 0
debug3: tty_make_modes: 18 15
debug3: tty_make_modes: 30 0
debug3: tty_make_modes: 31 0
debug3: tty_make_modes: 32 0
debug3: tty_make_modes: 33 0
debug3: tty_make_modes: 34 0
debug3: tty_make_modes: 35 0
debug3: tty_make_modes: 36 1
debug3: tty_make_modes: 37 0
debug3: tty_make_modes: 38 1
debug3: tty_make_modes: 39 0
debug3: tty_make_modes: 40 0
debug3: tty_make_modes: 41 1
debug3: tty_make_modes: 50 1
debug3: tty_make_modes: 51 1
debug3: tty_make_modes: 52 0
debug3: tty_make_modes: 53 1
debug3: tty_make_modes: 54 1
debug3: tty_make_modes: 55 1
debug3: tty_make_modes: 56 0
debug3: tty_make_modes: 57 0
debug3: tty_make_modes: 58 0
debug3: tty_make_modes: 59 1
debug3: tty_make_modes: 60 1
debug3: tty_make_modes: 61 1
debug3: tty_make_modes: 62 0
debug3: tty_make_modes: 70 1
debug3: tty_make_modes: 71 0
debug3: tty_make_modes: 72 1
debug3: tty_make_modes: 73 0
debug3: tty_make_modes: 74 0
debug3: tty_make_modes: 75 0
debug3: tty_make_modes: 90 1
debug3: tty_make_modes: 91 1
debug3: tty_make_modes: 92 0
debug3: tty_make_modes: 93 0
debug1: channel request 0: shell
debug1: fd 4 setting TCP_NODELAY
debug2: callback done
debug1: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 131072
-----------------------
:ssh -vvv 127.0.0.1
OpenSSH_3.7.1p2, SSH protocols 1.5/2.0, OpenSSL 0.9.7c 30 Sep 2003
debug1: Reading configuration data /usr/local/etc/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to 127.0.0.1 [127.0.0.1] port 22.
debug1: Connection established.
debug1: identity file /opt/home/user/.ssh/identity type 0
debug1: identity file /opt/home/user/.ssh/id_rsa type -1
debug3: Not a RSA1 key file /opt/home/user/.ssh/id_dsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /opt/home/user/.ssh/id_dsa type 2
debug1: Remote protocol version 2.0, remote software version OpenSSH_
3.7.1p2
debug1: match: OpenSSH_3.7.1p2 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.7.1p2
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-
hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-
ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-
ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-
hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-
ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-
ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 122/256
debug2: bits set: 1571/3191
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /opt/home/user/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug1: Host '127.0.0.1' is known and matches the DSA host key.
debug1: Found key in /opt/home/user/.ssh/known_hosts:2
debug2: bits set: 1564/3191
debug1: ssh_dss_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /opt/home/user/.ssh/id_rsa (0)
debug2: key: /opt/home/user/.ssh/id_dsa (648f0)
debug1: Authentications that can continue: publickey,password,keyboard-
interactive
debug3: start over, passed a different list publickey,password,keyboard-
interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /opt/home/user/.ssh/id_rsa
debug3: no such identity: /opt/home/user/.ssh/id_rsa
debug1: Offering public key: /opt/home/user/.ssh/id_dsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-dss blen 433
debug2: input_userauth_pk_ok: fp
87:79:73:a6:af:97:1d:80:27:d8:34:b1:23:75:ba:96
debug3: sign_and_send_pubkey
debug1: read PEM private key done: type DSA
debug1: Authentication succeeded (publickey).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Entering interactive session.
debug2: callback start
debug2: ssh_session2_setup: id 0
debug2: channel 0: request pty-req
debug3: tty_make_modes: ospeed 38400
debug3: tty_make_modes: ispeed 38400
debug3: tty_make_modes: 1 3
debug3: tty_make_modes: 2 28
debug3: tty_make_modes: 3 127
debug3: tty_make_modes: 4 21
debug3: tty_make_modes: 5 4
debug3: tty_make_modes: 6 0
debug3: tty_make_modes: 7 0
debug3: tty_make_modes: 8 17
debug3: tty_make_modes: 9 19
debug3: tty_make_modes: 10 26
debug3: tty_make_modes: 11 25
debug3: tty_make_modes: 12 18
debug3: tty_make_modes: 13 23
debug3: tty_make_modes: 14 22
debug3: tty_make_modes: 16 0
debug3: tty_make_modes: 18 15
debug3: tty_make_modes: 30 0
debug3: tty_make_modes: 31 0
debug3: tty_make_modes: 32 0
debug3: tty_make_modes: 33 0
debug3: tty_make_modes: 34 0
debug3: tty_make_modes: 35 0
debug3: tty_make_modes: 36 1
debug3: tty_make_modes: 37 0
debug3: tty_make_modes: 38 1
debug3: tty_make_modes: 39 0
debug3: tty_make_modes: 40 0
debug3: tty_make_modes: 41 1
debug3: tty_make_modes: 50 1
debug3: tty_make_modes: 51 1
debug3: tty_make_modes: 52 0
debug3: tty_make_modes: 53 1
debug3: tty_make_modes: 54 1
debug3: tty_make_modes: 55 1
debug3: tty_make_modes: 56 0
debug3: tty_make_modes: 57 0
debug3: tty_make_modes: 58 0
debug3: tty_make_modes: 59 1
debug3: tty_make_modes: 60 1
debug3: tty_make_modes: 61 1
debug3: tty_make_modes: 62 0
debug3: tty_make_modes: 70 1
debug3: tty_make_modes: 71 0
debug3: tty_make_modes: 72 1
debug3: tty_make_modes: 73 0
debug3: tty_make_modes: 74 0
debug3: tty_make_modes: 75 0
debug3: tty_make_modes: 90 1
debug3: tty_make_modes: 91 1
debug3: tty_make_modes: 92 0
debug3: tty_make_modes: 93 0
debug2: channel 0: request shell
debug2: fd 4 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 131072
---------------------
THE FOLLOWING TESTS WERE DONE WITH VERSION 3.7.1p2
---------------------
:dd if=/dev/zero of=/tmp/file bs=1k count=128k
131072+0 records in
131072+0 records out
:time ssh localhost "cat /tmp/file" >/tmp/file2

real 0m32.456s
user 0m27.230s
sys 0m3.280s
:time ssh localhost "cat /tmp/file" >/tmp/file2

real 0m32.824s
user 0m27.220s
sys 0m3.330s
:time ssh localhost "cat /tmp/file" >/tmp/file2

real 0m33.358s
user 0m26.980s
sys 0m3.570s
---------------------
:time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
32768+0 records in
32768+0 records out

real 0m10.848s
user 0m8.020s
sys 0m0.750s
:time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
32768+0 records in
32768+0 records out

real 0m10.795s
user 0m8.040s
sys 0m0.770s
:time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
32768+0 records in
32768+0 records out

real 0m10.730s
user 0m7.890s
sys 0m0.860s
:time ssh localhost "dd if=/dev/zero bs=1k count=128k" >/dev/null
131072+0 records in
131072+0 records out

real 0m38.037s
user 0m28.560s
sys 0m3.260s
:time ssh localhost "dd if=/dev/zero bs=1k count=128k" >/dev/null
131072+0 records in
131072+0 records out

real 0m38.256s
user 0m28.430s
sys 0m3.160s
:time ssh localhost "dd if=/dev/zero bs=1k count=128k" >/dev/null
131072+0 records in
131072+0 records out

real 0m37.491s
user 0m28.540s
sys 0m3.330s
---------------------
THE FOLLOWING TESTS WERE DONE WITH VERSION 3.4p1
---------------------
:time ssh localhost "cat /tmp/file" >/tmp/file2

real 0m21.294s
user 0m17.080s
sys 0m3.240s
:time ssh localhost "cat /tmp/file" >/tmp/file2

real 0m20.932s
user 0m17.020s
sys 0m3.390s
:time ssh localhost "cat /tmp/file" >/tmp/file2

real 0m21.138s
user 0m17.030s
sys 0m3.350s
---------------------
:time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
32768+0 records in
32768+0 records out

real 0m7.515s
user 0m4.980s
sys 0m0.780s
:time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
32768+0 records in
32768+0 records out

real 0m7.176s
user 0m4.950s
sys 0m0.950s
:time ssh localhost "dd if=/dev/zero bs=1k count=32k" >/dev/null
32768+0 records in
32768+0 records out

real 0m7.372s
user 0m5.030s
sys 0m0.820s
:time ssh localhost "dd if=/dev/zero bs=1k count=128k" >/dev/null
131072+0 records in
131072+0 records out

real 0m25.995s
user 0m18.820s
sys 0m3.110s
:time ssh localhost "dd if=/dev/zero bs=1k count=128k" >/dev/null
131072+0 records in
131072+0 records out

real 0m26.187s
user 0m18.320s
sys 0m3.330s
:time ssh localhost "dd if=/dev/zero bs=1k count=128k" >/dev/null
131072+0 records in
131072+0 records out

real 0m27.104s
user 0m18.450s
sys 0m3.200s
---------------------
and my own tests:
with version 3.4p1
:mkfile 100m file100m.bin
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
|*************************************************| 100 MB 00:16
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
|*************************************************| 100 MB 00:15
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
|*************************************************| 100 MB 00:15
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
|*************************************************| 100 MB 00:15

with version 3.7.1p2
:mkfile 100m file100m.bin
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
100MB 3.8MB/s 00:24
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
100MB 3.7MB/s 00:24
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
100MB 3.7MB/s 00:25
:scp file100m.bin 127.0.0.1:file100m.bin.2
file100m.bin 100%
100MB 3.8MB/s 00:23
---------------------

It certainly shows what I perceive to be a large disparity in performance
between versions. Any further thoughts/help would be greatly
appreciated.

stor

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