#arpnetworks 2013-12-19,Thu

brycec

Full disclaimer I've never used Varnish. Looked at it, but purely out of curiosity.

staticsafe

i wish I had the need for it though

brycec

ditty
*ditto

robonerd

url to varnish?

up_the_irons

toddf: whoa that's awesome

https://www.varnish-cache.org/

mnathani

robonerd

up_the_irons :)
mnathani ty
yea varnish looks useful
pure C or?

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[17:07]

mnathani

I just switched to varnish, but my pages are still not being cached. :-(

[17:19]

m0unds

boo

[17:19]

brycec

I'd say it's time to check that the backend servers aren't sending do-not-cache headers
(tcpdump)
And of course check that varnish is configured correctly :p
Relevant https://www.varnish-cache.org/content/why-isnt-varnish-caching-requests-seem-pass-straight-through

[17:20]

mnathani

Thanks

[17:21]

brycec

Apparently Cookies?
mnathani: easy test on the cookies: cURL
I swear curl is 90% of my web server debugging toolkit

[17:21]

staticsafe

curl ftw

[17:23]

brycec

libcurl too, if you're writing programs

[17:23]

robonerd

how does libcurl help?
er, curl/libcurl

[17:27]

.... (idle for 15mn)

brycec

robonerd: rather than writing your own methods to open sockets etc, just use curl

[17:42]

robonerd

can you get the raw binary somehow?

[17:43]

brycec

robonerd: you mean the raw response from the server? yeah of course.

[17:43]

robonerd

the ppl in #osdev were speaking in the same way about dropbear last night

[17:44]

brycec

dropbear is an ssh server, not a client library

[17:44]

robonerd

well yea

[17:45]

m0unds

isn't dropbear gone?
i thought i'd heard it was KAPUT

[17:53]

staticsafe

[17:54]

................ (idle for 1h16mn)

mercutio

i prefer trafficserver to squid or varnish
m0unds: i hope not!
i like for multiple implementations of important projects to stick around

[19:10]

m0unds

i could have sworn it was dropbear that died
saw that it didn't, now i'm wondering what did die and i confused it with dropbear

[19:11]

mercutio

dropbear used to have vulnerabilities
and people didn't upgrade versions
and then some people did but didn't upgrade the version number

m0unds

was there a period where it wasn't maintained well?
or partially abandoned or anything like that?

mercutio

really ssh servers shouldn't say the version number clearly.
no idea
i use dropbear as a client these days
it works on old hp servers (ilo2) where openssh doesn't
it connects faster over high latency links

m0unds

mercutio

and it even connects faster over low latency links

[19:13]

m0unds

ever tried mosh?

[19:13]

mercutio

but it doesn't aggregate text as much
so it can be a little slower for some things, and show more constant information
like typing dmesg
in real access, latency seems better if anything
and it's pretty fast
and it's hundreds of msec faster if dropbear on both sides going international
dbclient -l root arp.meh.net.nz pwd 0.00s user 0.00s system 0% cpu 1.963 total
ssh -l root arp.meh.net.nz pwd 0.01s user 0.00s system 0% cpu 2.201 total
that's to openbsd openssh
which is 170msec away
weird ping is usually less than that
it's 1.45 seconds to a linux host at arp
with dropbear server
i still kind of wish the handshaking was quicker
oh mosh was hell slow for me
it was laggy with 10 msec ping
but one of the ends was using atom at the time
and it's very cpu hungry it seems
i thought mosh was a novel idea, but i don't like using hugely inefficient software

[19:13]

m0unds

i typically only use it on my laptop because connectivity is so variable it saves me from having to reconnect regularly
never really noticed significant cpu utilization at either end

[19:17]

mercutio

ahh
well atoms are pretty slow

m0unds

yea
macbook is an i7

mercutio

it couldn't do samba at gigabit speeds

m0unds

server i was working with was a dual xeon
ahh, bummer

mercutio

xeon doesn't mean much :)
it's like saying a gas car :)

m0unds

m0unds is too lazy to go look

mercutio

anyway, mosh still uses ssh to connect

m0unds

mid 2012
whatever

mercutio

so recent

m0unds

192gb ram
etc

mercutio

yeah
probably a e5 of sorts
e5-2690 or something maybe

m0unds

wouldn't have dismissed cpu perf of a 10 year old xeon or something as being a reason for low cpu utilization...
herp derp

mercutio

oh right
the old pentium4 type xeons were hell slow
err 5000 series

m0unds

yep, netburst is a joke
bad arch

mercutio

well about as bad as atom

m0unds

good at warming up a room though

mercutio

not really

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mercutio

maybe a small room

m0unds

3.2GHz prescott was like a 130W cpu

mercutio

tdp

m0unds

or something absurd

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mercutio

they still don't use that much power normally
power supplies have got more efficient since then
and there's been some better idle, gating etc support
and cpus run closer to 0% load now
but in reasonable to high usage there's not much diff between old and newer cpus really
like 5000 series to 5400 series isn't huge jump
5400 to 5500 is a bit
5500 to 5600 is tiny i think
then a bit of a jump again from 5600 to whatever the next series was
is that e3 next?
it is isn't it
e3/35
e3/e5
and the affordable e5s aren't much faster than i5-2600s
err i7-2600
and power/efficiency/performance has hardly changed since then again
apparently ivy bridge cpus are more efficient than haswell at load
i suppose amd kind of fell off the train, so intel doesn't have aynone to compete with except arm type things that are coming up

[19:22]

m0unds

amd still does well in hpc

mercutio

with video cards?

m0unds

mostly because of thread count
haven't seen a lot of amd powered gpu compute
nvidia seems to own that space

mercutio

you mean stuff that powerpc is winning in power/performance?
that's curious
consdiering that amd is much better than nvidia at bitcoin
i assumed that amd was better in general with opencl type things

m0unds

yea, i think part of it is opencl vs cuda
cuda being more ubiquitous
which is silly

[19:27]

mercutio

i haven't touched either
it sounded like a nice idea
i've been playing with ssd raid
adn reading up about stuff

[19:27]

m0unds

i think cuda's been around longer, sorta like physx or whatever in teh gaming world

mercutio

it seeems intel motherboards can't do more than about 1500mb/sec on onboard sata

m0unds

so adoption is higher

mercutio

cos they have a 2GB/sec link for pci-e

m0unds

intel mobo w/the SATA controller attached at the southbridge or a separate controller like marvell or whatever it was they used?

mercutio

x4 i suppose
intel onboard direct
i get about 1400mb/sec with x4 pci-e x2
err pci-e 2
i think slightly over 1400mb/sec
so i suppose it basically it is x4 limitations
at x8 i was getting faster speeds
but at those speeds it doesn't amtter too much
but i think i/o bus speeds for non video is likely to be the next significant improvement
video cards are iommu now
err can do iommu
it may not be that far away that there are dual cpus on small computers
with a lower power fanless cpu and a full cpu

m0unds

that's something AMD's working on, actually
arm + x86

[19:32]

mercutio

oh, interesting
arm already do that kind of thing

[19:32]

m0unds

http://www.amd.com/us/aboutamd/newsroom/Pages/presspage2012Oct29.aspx
first step is servers

[19:32]

mercutio

that's damn cool.
time xterm -e pwd" isn't much faster than it was on a p120.

[19:33]

m0unds

that + APU stuff (xbox, ps4, low-end laptops) are where they're really kinda pushing stuff a bit

[19:34]

mercutio

there's lots of inbuilt latency etc limitations
and downclocking big cpus is probably not going to keep latency low
i haven't really considered amd seriously for years
last i knew their memory performance and single threaded performance was way down

[19:34]

m0unds

yep
multithreaded performance is stellar

mercutio

and most things don't scale to multicore

m0unds

yep

mercutio

which is what i wondered about back with pentium pros
not much scales on linux yet
lbzip2 is damn cool.
compiling scales well
but i think we're really close to needing things like multithreaded file copying
like if you copy 100,000 files
it shouldn't iterate through the files one by one
but on single hard-disks they don't really cope with multiple transactions at once well
but ssd's and raid arrays should be ok

m0unds

having lots of threads for encoding (single encode process per core) is nice

[19:37]

mercutio

so that's my personal thing i wnat to look at soon
for multiple files?

[19:37]

m0unds

yep

[19:38]

mercutio

yeah multipel files is easy
i don't do any encoding myself
i don't even do mp3 encoding from cd's

[19:38]

m0unds

i do some audio work for friends, occasionally do video

mercutio

but cpus are fast enough now that single cpu'ing that is still going to keep up with the cd

m0unds

yea

mercutio

i ripped heaps of music years back

m0unds

17 seconds to encode a 70 minute album from wav -> flac or wav, flac or whatever -> other format
it's pretty hilarious

mercutio

heh

m0unds

doing 8 tracks at once

[19:40]

mercutio

it used to use up 50% cpu to play a mp3
and i had to fuck around with nice lervels and shit
to make sure it didn't skip

[19:40]

m0unds

i couldn't play mp3s on the machine i had til i was in HS
cpu was too slow, 486DX-33
haha

[19:40]

mercutio

haha
i went 486dlc40 to p75 i think
err
it was 486dlc40 to some amd thingy
like a fast 486
with a weird name
then to a p120

[19:41]

m0unds

i went 486dx-33 4MB RAM -> 20MB RAM -> 300MHz AMD K6-2

[19:42]

mercutio

i overclocked the p120 to 133 mhz and removed the fan
so much headroom in those days
4mb ram gotta suck

[19:42]

m0unds

it was cutting edge in 1993
double speed cdrom too

mercutio

heh
shit 91
mp3s were around in 91?
oh you said 93
how did i read it as 91

m0unds

yeah, i had that machine til 1999
hahaha

mercutio

heh
i got amd k6-2 sometime too
with 128mb of ram

m0unds

cdrom interface was via the isa soundcard

mercutio

i had 24mb before that
and couldn't run X

m0unds

i didn't have enough vram in the 486 to run x at higher than 640x480

mercutio

heh
did you overclock isa bus?

m0unds

nah

mercutio

i didn't have enough memory
i think i had s3 virge
i just used svgatext mode

m0unds

my 486 was 1MB cirrus logic or something
i could get 800x600 in wfw 3.11

mercutio

and had like 100 columns or so
heh
i dunno how much memory i had
probably 2mb?
i think it was s3 trio64

[19:45]

m0unds

i have a pci version of one of those somewhere
s3 trio or verge maybe

[19:45]

mercutio

lots of people had vergs
trios were cheaper
i went to radeon 9000
which could do 1920x1440?
but on crt that flickered heaps
i usually just used 1280x1024

[19:46]

m0unds

yeah, probably low refresh or whatever
yeah, same

[19:46]

mercutio

and then got annoyed with the lack of space sometimes and jumped up to 1600x1200
yeah 1280x1024 was 85 hertz
and 1920x1440 was like 60 hertz
1600x1200 75 hertz or something
19" crt
but when youwent up resolution things got less crisp
but yeah everything uses up so much memory niow
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
17037 root 20 0 333392 100136 80780 S 2.7 1.2 0:09.62 Xorg
i have 5 xterms open, and pidgin
but i was surprised how well linux seems to deal with 8gb of ram
compared to windopws
sometime memopry volumes went up enough that it doesn't really matter now

[19:47]

m0unds

i've got 2GB free in win7 right now on this particular workstation

[19:50]

mercutio

on 8gb ram?

m0unds

yep

mercutio

i have 5 gb free on 16gb right now
on the windows box
but i'm running chrome

m0unds

probably superfetch caching stuff

mercutio

and skype and putty
i disabled that stuff

m0unds

why?

mercutio

cos samsung told me to

m0unds

lol

mercutio

samsung magician software suggests you disable it

m0unds

hahah

my corsair SSD has 3 years of use and still indicates 100% wear level with like 8TB of writes

mercutio

i dunno i had 8gb for a while in it
cos i was curious how it'd go
(i default to thinking 16gb makse sense thse days)

m0unds

i wonder if it's a write-saving measure for samsung
yea, my home ws is 16gb
this one's at my office

mercutio

and i noticed the upgrade to 16
it's cos i junmped from 6 to 16 and thought 8 may have been enough
but i'm in similar situation with my linux bvox too
i have ram lying around
i could upgrade to 16gb or 24gb on server
but it's on 8gb
and i run chrome on it too
and it deals much better on 8gb
and i dual boot the windows box with linux too
and i notice no diff between 8/16
my original justification was for virtualisation though
and i was doing linux and windows on the same box for a bit
and upgrading from 16 to 24gb helped