* 127.0.0.1 considered harmful
@ 2020-07-11 11:04 Richard Miller
2020-07-11 15:46 ` [9fans] " Ethan Gardener
0 siblings, 1 reply; 6+ messages in thread
From: Richard Miller @ 2020-07-11 11:04 UTC (permalink / raw)
To: 9fans
This seems weird to me:
cpu% echo $sysname
atom
cpu% ndb/query sys atom ip
192.168.23.25
cpu% ndb/query sys localhost ip
127.0.0.1
cpu% srv atom atom /n/atom
post...
cpu% srv localhost localhost /n/localhost
post...
cpu% time cp /n/atom/386/9pccpuf /dev/null
0.00u 0.02s 0.37r cp /n/atom/386/9pccpuf /dev/null
cpu% time cp /n/localhost/386/9pccpuf /dev/null
0.00u 0.00s 24.54r cp /n/localhost/386/9pccpuf /dev/null
cpu% time cp /n/atom/386/9pccpuf /dev/null
0.00u 0.00s 0.14r cp /n/atom/386/9pccpuf /dev/null
cpu% time cp /n/localhost/386/9pccpuf /dev/null
0.00u 0.00s 24.87r cp /n/localhost/386/9pccpuf /dev/null
Intuitively I would have thought the loopback interface would
be more efficient than going through the ethernet driver.
Certainly not two orders of magnitude slower.
This is on a 386-based cpu + fossil server. The same experiment
on arm and cwfs gives similar results.
It's not about raw bandwidth; streaming in one direction seems ok:
cpu% tcptest & tcptest -i atom -n 10000
cpu% tcp!192.168.23.25!34061 count 10000; 81920000 bytes in 2016503491 ns @ 40.6 MB/s (0ms)
cpu% tcptest & tcptest -i localhost -n 10000
cpu% tcp!127.0.0.1!49090 count 10000; 81920000 bytes in 551924026 ns @ 148 MB/s (0ms)
So the problem seems to be latency of 9p transactions. Could it be
an artifact of tcp flow control not adapting well to the loopback
interface? Can anyone offer an insight?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [9fans] 127.0.0.1 considered harmful
2020-07-11 11:04 127.0.0.1 considered harmful Richard Miller
@ 2020-07-11 15:46 ` Ethan Gardener
2020-07-11 18:24 ` David du Colombier
2020-07-13 7:04 ` Lucio De Re
0 siblings, 2 replies; 6+ messages in thread
From: Ethan Gardener @ 2020-07-11 15:46 UTC (permalink / raw)
To: g_patrickb via 9fans
On Sat, Jul 11, 2020, at 12:04 PM, Richard Miller wrote:
> So the problem seems to be latency of 9p transactions. Could it be
> an artifact of tcp flow control not adapting well to the loopback
> interface? Can anyone offer an insight?
A comment in the default /lib/ndb/local makes me think the loopback interface was a bit of an afterthought. It's this one:
#
# because the public demands the name localsource
#
ip=127.0.0.1 sys=localhost dom=localhost
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [9fans] 127.0.0.1 considered harmful
2020-07-11 15:46 ` [9fans] " Ethan Gardener
@ 2020-07-11 18:24 ` David du Colombier
2020-07-11 18:57 ` Richard Miller
2020-07-13 7:04 ` Lucio De Re
1 sibling, 1 reply; 6+ messages in thread
From: David du Colombier @ 2020-07-11 18:24 UTC (permalink / raw)
To: g_patrickb via 9fans
I think you may be experiencing an issue I investigated
and fixed a few years ago, due to the TCP stack not
setting up the MTU properly on incoming connections.
You can look at this old thread from 9fans:
https://www.mail-archive.com/9fans@9fans.net/msg33754.html
The fix is available here:
http://9legacy.org/9legacy/patch/9-tcp-mss.diff
--
David du Colombier
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [9fans] 127.0.0.1 considered harmful
2020-07-11 15:46 ` [9fans] " Ethan Gardener
2020-07-11 18:24 ` David du Colombier
@ 2020-07-13 7:04 ` Lucio De Re
2020-07-17 9:40 ` Ethan Gardener
1 sibling, 1 reply; 6+ messages in thread
From: Lucio De Re @ 2020-07-13 7:04 UTC (permalink / raw)
To: 9fans
On 7/11/20, Ethan Gardener <eekee57@fastmail.fm> wrote:
> #
> # because the public demands the name localsource
> #
> ip=127.0.0.1 sys=localhost dom=localhost
>
Yes, someone should submit a legacy patch just to correct the comment!
Lucio.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [9fans] 127.0.0.1 considered harmful
2020-07-13 7:04 ` Lucio De Re
@ 2020-07-17 9:40 ` Ethan Gardener
0 siblings, 0 replies; 6+ messages in thread
From: Ethan Gardener @ 2020-07-17 9:40 UTC (permalink / raw)
To: g_patrickb via 9fans
On Mon, Jul 13, 2020, at 8:04 AM, Lucio De Re wrote:
> On 7/11/20, Ethan Gardener <eekee57@fastmail.fm> wrote:
> > #
> > # because the public demands the name localsource
> > #
> > ip=127.0.0.1 sys=localhost dom=localhost
> >
> Yes, someone should submit a legacy patch just to correct the comment!
An easy patch, but I rather like the comment. It amuses me. ;)
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-07-17 9:40 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-11 11:04 127.0.0.1 considered harmful Richard Miller
2020-07-11 15:46 ` [9fans] " Ethan Gardener
2020-07-11 18:24 ` David du Colombier
2020-07-11 18:57 ` Richard Miller
2020-07-13 7:04 ` Lucio De Re
2020-07-17 9:40 ` Ethan Gardener
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