From: Nate Clark <nate@pivotallabs.com>
To: Lawrence Pit <lawrence.pit@gmail.com>
Cc: unicorn list <mongrel-unicorn@rubyforge.org>
Subject: Re: workers not utilizing multiple CPUs
Date: Tue, 31 May 2011 20:20:14 +0800 [thread overview]
Message-ID: <BANLkTinX0t35a7Mu1vk=DwxwO6EZj-gptA@mail.gmail.com> (raw)
In-Reply-To: <4DE4DABB.3070503@gmail.com>
Lawrence,
I've suspected that it may be a monitoring problem and not a Unicorn
problem, but I'm not yet convinced either way. Our monitoring via
collectd is done through Rightscale. They have a lot of experience
with EC2, so I'd assume that it is monitoring properly. Also, our
other services (mysql, for example) are showing activity on multiple
cores under load, so that leads me to believe that the monitoring is
working in at least some cases.
I wasn't aware of the Cloudwatch service until now, that looks
interesting ... I'll check it out.
Anyone else experience a problem like this?
Nate
On Tue, May 31, 2011 at 8:10 PM, Lawrence Pit <lawrence.pit@gmail.com> wrote:
> Hi Nate,
>>
>> We've been watching the CPU
>> graphs from collectd data when the website is under load, and only
>> cpu-0 shows any activity ... the others seem to be idle, or minimally
>> used by other services.
>
> I don't think you can rely on the numbers collectd (nor top) gives you when
> measuring from within the hypervisor powering your EC2 instance. The only
> reliable source of CPU utilization is Cloudwatch, as that measures outside
> your instances.
>
> I've used an array of xlarge instances myself, each running 17 unicorn
> workers serving a rails app, consuming 4GB, leaving 3GB, no swap. Worked
> well for us under high load. It couldn't have handled that if all 17 unicorn
> workers would've been served by 1 of those 8 virtual cores.
>
>
> Cheers,
> Lawrence
>
>
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next prev parent reply other threads:[~2011-05-31 12:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-31 9:02 workers not utilizing multiple CPUs Nate Clark
2011-05-31 12:10 ` Lawrence Pit
2011-05-31 12:20 ` Nate Clark [this message]
2011-05-31 14:07 ` Clifton King
2011-05-31 15:48 ` Eric Wong
2011-05-31 15:55 ` Clifton King
[not found] ` <BANLkTikC5D+0pUDRDgvQbzu=dpwmdKNY=A@mail.gmail.com>
2011-06-01 6:51 ` Nate Clark
2011-05-31 15:27 ` Eric Wong
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