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From Robert Newson <robert.new...@gmail.com>
Subject Re: CouchDB bleeding CPU
Date Wed, 10 Oct 2012 14:25:53 GMT
Sorry, I meant that R15B02's scheduler could be the cause of this, not
a solution. Since you're not using it, it's obviously not that.

If you're making no requests and /_active_tasks is empty and beam is
still chewing CPU, then that's a bit of a puzzle.

Sent from the ocean floor

On 10 Oct 2012, at 14:37, Pekka Olavi <pekka.korolainen@gmail.com> wrote:

> Thanks Dave and Robert!
>
> Actually, from the ten threads spawned two are doing this, the other
> about 10x more than the other. As far as I understand, the engine
> should be doing nothing (it's almost empty, just on db with 2 design
> docs and 4 normal ones), so this scheduling thingy Robert mentioned
> seems like a good candidate to start with. I'm currently at R14B02,
> I'll upgrade and see what happens with a newer version.
>
> .p
>
> On Wed, Oct 10, 2012 at 4:24 PM, Robert Newson <robert.newson@gmail.com> wrote:
>> http://dieswaytoofast.blogspot.com.es/2012/09/cpu-utilization-in-erlang-r15b02.html?m=1
>>
>> Sent from the ocean floor
>>
>> On 10 Oct 2012, at 14:23, Robert Newson <robert.newson@gmail.com> wrote:
>>
>> I recall R15B02, perhaps earlier, introduced a scheduler that kept the
>> CPU hot to eliminate delays when changing state from idle. I read that
>> somewhere recently, but can't find the link.
>>
>> Sent from the ocean floor
>>
>> On 10 Oct 2012, at 13:05, Dave Cottlehuber <dch@jsonified.com> wrote:
>>
>> On 10 October 2012 13:50, Pekka Olavi <pekka.korolainen@gmail.com> wrote:
>>
>> Hello folks, I run a couch on my desktop for testing purposes.
>>
>> Everything else is fine and dandy and I'm actually loving developing
>>
>> for the web with couch. There is one gripe though, the beam.smp
>>
>> process is bleeding the CPU, for some reason I have no proficiency to
>>
>> analyse.
>>
>>
>> http://pastebin.com/eqtUyNZS
>>
>>
>> I start the server with "sudo couchdb" and it shows up in my ps aux like so:
>>
>> /usr/lib/erlang/erts-5.8.3/bin/beam.smp -Bd -K true -A 4 -- -root
>>
>> /usr/lib/erlang -progname erl -- -home /home/halides -- -noshell
>>
>> -noinput -os_mon start_memsup false start_cpu_sup false
>>
>> disk_space_check_interval 1 disk_almost_full_threshold 1 -sasl
>>
>> errlog_type error -couch_ini /usr/local/etc/couchdb/default.ini
>>
>> /usr/local/etc/couchdb/local.ini -s couch
>>
>>
>> Any help appreciated!
>>
>>
>> .p
>>
>>
>> Hi Pekka,
>>
>>
>> What is couchdb doing at the time? e.g. are you view indexing,
>>
>> whatever. Anything in the couch.log when running in debug mode?
>>
>>
>> None of this will fix the problem, but it might be helpful to note
>>
>> what OS you're running as well, and how erlang was compiledm (or
>>
>> rpmd).
>>
>>
>> Some of the flags you are using seem wrong if you are intending to
>>
>> enable kernel polling and increase the IO scheduler threads.
>>
>>
>> -A 4 should be +A 4
>>
>> -K true should be +K true
>>
>> ditto for your +Bd option
>>
>>
>> You might be interested in some of the tricks in here
>>
>> http://erlang-in-production.herokuapp.com/#16 from archaelus, and let
>>
>> us know what processes are hogging.
>>
>>
>> After that, I think your best bet will be to hop on irc in #erlang or
>>
>> #erlounge and get some other smart ideas.
>>
>>
>> A+
>>
>> Dave

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