Re: [Debian-NYC] Thanks for yesterday!

On Thu, Dec 2, 2010 at 1:53 PM, Daniel Kahn Gillmor <dkg@fifthhorseman.net> wrote:

On 12/02/2010 12:39 PM, steve beltzer wrote:
> Hi Daniel,,
>
> Just took me 2 minutes 15 seconds to load nytimes.com via IceWeasel and
> wireless.
>
> the video runs smoothly when downloaded from nytimes.com though...
>
> 1 minute and 45 seconds to load nytimes.com with epiphany and wireless
>
> 2 minutes 10 seconds with loading nytimes.com via IceWeasel with cable
> connection
>
> 1 minute 50 seconds with epiphany and cable connection....

yow, that's certainly slow. i see under 10 seconds for the same page
from a clean cache (although i'm not using _javascript_ or flash). And it
doesn't sound like the delay changes significantly when you switch
connections.

i assume your times under the other OS are comparable to 10 seconds for
the page?

Can you show some profiling info under debian? Here's one way.

Make sure iceweasel is already open and running, but only on a blank page:

iceweasel about:blank

then in another terminal, do:

vmstat 2 10 & sleep 8 && iceweasel http://nytimes.com & wait

when i do this, i get the following results:

>> 0 dkg@pip:~$ vmstat 2 10 & sleep 8 && iceweasel http://nytimes.com & wait
>> [1] 2245
>> [2] 2246
>> procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
>> r b swpd free buff cache si so bi bo in cs us sy id wa
>> 0 0 93688 112940 59928 428576 0 1 14 34 126 64 12 4 81 4
>> 0 0 93688 112960 59928 428536 0 0 0 0 65 133 1 0 100 0
>> 0 0 93688 112960 59936 428536 0 0 0 40 69 142 0 0 99 0
>> 0 0 93688 112960 59936 428536 0 0 0 0 63 121 1 0 100 0
>> 1 0 93688 112932 59936 428536 0 0 0 0 61 124 0 0 100 0
>> 1 0 93688 102392 59956 437572 0 0 232 10 431 3471 80 12 7 1
>> 1 1 93688 107476 59964 431712 0 0 46 150 319 393 93 3 0 4
>> 0 1 93688 107724 59976 430968 0 0 0 96 94 371 3 1 0 95
>> 0 0 93688 107848 59996 430848 0 0 0 130 89 240 2 0 83 15
>> 0 0 93688 107656 60012 430824 0 0 0 108 125 251 17 1 44 39
>> [1]- Done vmstat 2 10
>> [2]+ Done sleep 8 && iceweasel http://nytimes.com
>> 0 dkg@pip:~$

each line of output past the header shows the state of the system's
resources; the first shows the average since the most recent boot, and
each subsequent line shows the info for every 2 seconds (that's the "2"
in "vmstat 2 10").

Looking at the columns under the ---cpu--- heading, you can see that 8
seconds after startup, iceweasel kicks in and the CPU goes from 100%
idle to 80% active in user space and 12% active in the kernel.

so it does this for about 4 seconds, and then iceweasel tediously tries
to update its on-disk cache: spending 95% of its time in the "wait"
state, which means the CPU is idle, but there are things that could run
if the disk I/O would complete.

What does yours look like? I can help you interpret it if you post it here.

If you're interested in this kind of troubleshooting, you might want to
read:

http://cmrg.fifthhorseman.net/wiki/DiagnosingSluggishness

hth,

--dkg

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