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From 牛兆捷 <nzjem...@gmail.com>
Subject Re: performance of block cache
Date Thu, 21 Aug 2014 03:19:36 GMT
Hi Nick:

Yes, I am interested in it. I will try first.

Btw, this site (http://people.apache.org/~stack/bc/) also does the similar
performance evaluation.
You can have a look if you are interested in.


2014-08-21 1:48 GMT+08:00 Nick Dimiduk <ndimiduk@gmail.com>:

> Hi Zhaojie,
>
> I'm responsible for this particular bit of work. One thing to note in these
> experiments is that I did not control explicitly for OS caching. I ran
> "warmup" workloads before collecting measurements, but because the amount
> of RAM on the machine is fixed, it's impact of OS cache is different with
> different based on the amount of memory used by HBase. Another, as Todd
> pointed out on an earlier thread, is that my trend lines are probably
> optimistic/misleading.
>
> Something I was driving for was to understand how well the different
> implementations before as they're managing more and more memory. I'd like
> to get some insight into how we might be able to take advantage of 100's or
> even 1000's of GB of memory when the time comes. That's part of why there's
> so many variables.
>
> I scripted out the running of the tests, all of my configurations are
> available in the associated github repo [0], and all of the data points are
> available as a csv. If you're interested in experimenting yourself, please
> let me know how I can help.
>
> Cheers,
> Nick
>
> [0]: https://github.com/ndimiduk/perf_blockcache
>
>
> On Wed, Aug 20, 2014 at 6:00 AM, 牛兆捷 <nzjemail@gmail.com> wrote:
>
> > the complete blog link is:
> > http://zh.hortonworks.com/blog/blockcache-showdown-hbase/
> >
> >
> > 2014-08-20 11:41 GMT+08:00 牛兆捷 <nzjemail@gmail.com>:
> >
> > > Hi all:
> > >
> > > I saw some interesting results from Hortonworks blog (block cache
> > > <
> >
> http://zh.hortonworks.com/wp-content/uploads/2014/03/perfeval_blockcache_v2.pdf
> > >
> > > ).
> > >
> > > In this result, the ratio of memory footprint to database size is held
> > > fixed while
> > > the absolute values are increased.
> > >
> > > In my mind, the performance should becomes worse for larger ratio as
> the
> > > increase
> > > of the absolute value. For example BucketCache#(tmpfs), the difference
> > > between ratio (DB"1.5":"RAM"1.0) and ratio (DB"4.5":"RAM"1.0) becomes
> > > larger as the increase of memory.
> > > Actually, the result of ratio ( DB"1.5":"RAM"1.0) increase linearly,
> and
> > > the result of ratio (DB"1.5":"RAM"1.0) exponentially.
> > >
> > > However, for BucketCache#(heap) and LruBlockCache, the result is out of
> > my
> > > expectation.
> > > The curves of ratio (DB"1.5":"RAM"1.0) and ratio (DB"4.5":"RAM"1.0)
> both
> > > increase exponentially, but the relative differences as the increase of
> > > memory are not consistent.
> > > Take LruBlockCache as an example, the difference of ratio
> > > (DB"1.5":"RAM"1.0) and ratio (DB"4.5":"RAM"1.0) becomes smaller from 20
> > GB
> > > to 50 GB, but becomes larger from 50 GB to 60 GB.
> > >
> > > How to analysis the cause of this result, any ideas?
> > >
> > > --
> > > *Regards,*
> > > *Zhaojie*
> > >
> > >
> >
> >
> > --
> > *Regards,*
> > *Zhaojie*
> >
>



-- 
*Regards,*
*Zhaojie*

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