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From Michael André Pearce <>
Subject Re: Paging
Date Sat, 01 Apr 2017 22:35:10 GMT
Hi Franz,

Sorry if its obvious, will this be in the 2.0.1 release that Clebert just announced to look
to be tagged soon?

If so, with work time constraints, as we are focused on rolling out new brokers, ill try to
run this on the setup we have currently on our physical server lab with ssd's, and try get
some feedback.

One note i have, if the disks you’re using are SSD’s of data centre quality (e.g. Intel
s3610, s3710), i would expect them to have write cache’s with capacitor backed to guarantee
the write even on lights out, as such especially as SSD in the data centre becomes more prevalent.
Im unclear why you’d run or you’re recommending with disabling the disk cache's?


> On 1 Apr 2017, at 08:14, nigro_franz <> wrote:
> BIG Update:
> I've just completed the performance work to make the MAPPED Journal suitable
> to be used as a full citizen Journal type for any kind of loads (concurrent
> and durable ones in particular).
> In order to make it suitable to be used with high loads of concurrent
> requests of persistent messages, I've performed these optimisations:
> 1) smart batching on concurrent/high-rate sync requests (different from NIO
> and ASYNCIO; it is high throughput *and* low latency, falling back to honor
> a configurable SLA on latency only when unable to achieve both)  
> 2) adapting (on the load) page prefetching/zeroing to make the write
> requests more sympathetic with the Unix/Windows paging caching policies and
> the hard disk sector sizes
> The change is huge and I'm thinking (need feedbacks!!) to make a different
> (the old one would be good) implementation of it for the PAGING: they
> satisfies different purposes and requires different optimisations.
> I prefer to not publish benchmark results and I've not updated the Artemis
> journal benchmark tool on purpose: it can't show the improvements easily due
> to the kind of optimisations done to make it faster on the common execution
> paths.
> On the other hand, I've reused the tuning performed by the tool on Artemis
> startup to configure the latency SLA of the journal and the write buffer
> size: hence a user will need only to set the Journal type on broker.xml and
> everything will work as the the ASYNCIO case (using its same properties,
> maxAIO excluded).
> I'll suggest to try it on real loads and disabling the disk HW write cache
> (eg hdparm -W 0 /dev/sda on Linux) to have consistent results: it is more
> sensible than the ASYNCIO journal to these hardware features, in particular
> due to the adapting prefetching feature I've put it in.
> The branch with its latest version is:  here
> <>  . 
> --
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