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From Pekka Olavi <pekka.korolai...@gmail.com>
Subject Re: CouchDB bleeding CPU
Date Wed, 10 Oct 2012 17:35:05 GMT
Yeah, I wasn't thinking that either. But I'm hoping running a more
state of the art erlang would be a good try to fix this :-)

On Wed, Oct 10, 2012 at 5:25 PM, Robert Newson <robert.newson@gmail.com> wrote:
> 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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