Hi, Running OpenSSH 3.5p1 or 3.7.1p2 on two SGI orgin 300 systems of IRIX 6.5.17 with 4 600MHz CPU and gigabits network. Transfer a 1GB file with ftp took 28 seconds. Transfer a 1GB file with scp took 148 seconds. Use "snoop" to capture all network packets between these two systems. Ftp tansmitted about 107840 packets, but scp transmitted about 763339 packets. Is this normal? Why? Also, did the same test on two IBM AIX 4.3.3 systems with 1 CPU and 10Mb network. Transfer a 1GB file with ftp took 1080 seconds Transfer a 1GB file with scp using blowfish took 1059 seconds. Ftp tansmitted about 207070 packets, but scp only transmitted only about 190290 packets. What a difference! Why? Thanks. Jay Chen
On Thu, 2003-11-06 at 09:21, Jay Chen wrote:> What a difference! Why?Coincidentally a topic of discussion recently on /. http://ask.slashdot.org/article.pl?sid=03/10/14/2134216&mode=nested&tid=126&tid=172&tid=95
Hi All, In one of our HP-UX system, the display of the terminal settings is not working when I configure my .profile file with the shell command [who -Rm]. I use "who -Rm" in my .profile for root user. When I login thro ssh, sometimes, the current terminal details are not printed, when the shell [I am using ksh] commands in the .profile file is executed. When we introduce a sleep command in the profile file before this who command, all the time the current terminal details gets printed. Is this an issue with the sshd that the child reads the utmp entry before the tty and records are properly written to utmp? Do anyone shed some light, how we can avoid this? Advance Thanks, Kumaresh. ----- Original Message ----- From: "Jay Chen" <jchen at pop500.gsfc.nasa.gov> To: <openssh-unix-dev at mindrot.org> Sent: Thursday, November 06, 2003 9:51 PM Subject: scp vs ftp performance on SGI IRIX????????> Hi, > > Running OpenSSH 3.5p1 or 3.7.1p2 on two SGI orgin 300 systems of IRIX > 6.5.17 with > 4 600MHz CPU and gigabits network. > > Transfer a 1GB file with ftp took 28 seconds. > Transfer a 1GB file with scp took 148 seconds. > > Use "snoop" to capture all network packets between these two systems. Ftp > tansmitted > about 107840 packets, but scp transmitted about 763339 packets. > > Is this normal? Why? > > Also, did the same test on two IBM AIX 4.3.3 systems with 1 CPU and 10Mb > network. > > Transfer a 1GB file with ftp took 1080 seconds > Transfer a 1GB file with scp using blowfish took 1059 seconds. > Ftp tansmitted about 207070 packets, but scp only transmitted only about > 190290 packets. > > What a difference! Why? > > Thanks. > > Jay Chen > _______________________________________________ > openssh-unix-dev mailing list > openssh-unix-dev at mindrot.org > http://www.mindrot.org/mailman/listinfo/openssh-unix-dev >--- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.520 / Virus Database: 318 - Release Date: 9/18/2003
On Thu, 6 Nov 2003, Jay Chen wrote:> Hi, > > Running OpenSSH 3.5p1 or 3.7.1p2 on two SGI orgin 300 systems of IRIX > 6.5.17 with > 4 600MHz CPU and gigabits network. > > Transfer a 1GB file with ftp took 28 seconds. > Transfer a 1GB file with scp took 148 seconds. >Which protocol? v1 or v2? what encryption is used? [..]> > What a difference! Why? >Could be as simple as the AIX server may be better at number crunching and the IRIX box can't encrypt fast enough to keep up with the stream of data. Good example is comparing a SS20 150mhz with a Intel 586 150mhz. The SS20 even at the speed of 150mhz is extremely poor at doing encyption. It was shown clearly in early version of OpenSSH v2 key exchange where it would "hang" for up to a minute and half. The Intel box cranked it right out and was done in less than half the time. - Ben
Jay Chen wrote:> > Hi, > > Running OpenSSH 3.5p1 or 3.7.1p2 on two SGI orgin 300 systems of IRIX > 6.5.17 with > 4 600MHz CPU and gigabits network. > > Transfer a 1GB file with ftp took 28 seconds. > Transfer a 1GB file with scp took 148 seconds. > > Use "snoop" to capture all network packets between these two systems > . Ftp tansmitted about 107840 packets, but scp transmitted about > 763339 packets.So, 1GB is 1048576 KB. 1048576 KB divided by 107840 packets is 9956.8 bytes per packet. That seems rather odd because it is larger even than the bytes per packet I would expect if JumboFrame (9000 byte MTU) were enabled. Does Irix 6.5.17 do "large send" over the GbE NIC? Perhaps there is a "sendfile()-like" call in Irix 6.5.17 that the Irix FTP uses With the scp, that is more like 1406 bytes per packet, which is more consistent with an MTU of 1500 bytes. Or perhaps scp has some application-level block size - I can never remember the specifics of SSL !-( It is somewhat "consistent" that the case that sent ~7x the packets took ~7x the time.> Also, did the same test on two IBM AIX 4.3.3 systems with 1 CPU and > 10Mb network. > > Transfer a 1GB file with ftp took 1080 seconds > Transfer a 1GB file with scp using blowfish took 1059 seconds. > Ftp tansmitted about 207070 packets, but scp only transmitted only > about 190290 packets.In this case, it is showing >> 1460 bytes per packet which is I believe rather impossible for a 10Mb network - I don't think any 10 Mbit/s NICs do jumboframes and I'm confident that AIX 4.3.3 doesnot support large send - I believe that came-in with patches to AIX 5.mumble (it is one of the reasons IBM has the SPECweb scores they do) Now, if there is compression of some sort I suppose that might explain some of it. Any chance that either ftp or scp were compressing the data? It might be a good idea to take snapshots of the netstat statistics from before and after each transfer - it is possible that the snoop traces aren't getting all the packets. You can then run the before and after netstats through "beforeafter" which you can find at ftp://ftp.cup.hp.com/dist/networking/tools/ source is included and I suspect it would compile without too much trouble on Irix and AIX. rick jones -- Wisdom Teeth are impacted, people are affected by the effects of events. these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to raj in cup.hp.com but NOT BOTH...
Jay Chen wrote:> Running OpenSSH 3.5p1 or 3.7.1p2 on two SGI orgin 300 systems of IRIX > 6.5.17 with > 4 600MHz CPU and gigabits network. > > Transfer a 1GB file with ftp took 28 seconds. > Transfer a 1GB file with scp took 148 seconds. > > Use "snoop" to capture all network packets between these two systems. Ftp > tansmitted > about 107840 packets, but scp transmitted about 763339 packets.Wild guess: does changing the shell pipe size (probably "ulimit -p") make any difference to scp? What's it set to by default? Also, do you have compression on or off? -- Darren Tucker (dtucker at zip.com.au) GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4 37C9 C982 80C7 8FF4 FA69 Good judgement comes with experience. Unfortunately, the experience usually comes from bad judgement.