Azure compute power: Extra Large VM slow

Question

Can anyone offer me any insights into why my cloud deployment would be slower than an on-premises computer in "horsepower" terms?

I have a compute intensive application which uses a worker role to carry out millions of computations (in parallel).

Currently in Azure I'm testing using an Extra Large (8 core, 16GB) VM to do the processing. On average it's taking 45 minutes per iteration whereas the same code running on a 4 core, 8GB on-premises machine was taking only 15 minutes.

Azure logs indicate total processor utilisation is 99% but I have 12GB memory free so I'll definitely try loading more data into memory for each iteration.

Are the 8 cores just individually very low spec? Is local storage really local? That is, is local storage really on a different physical device and therefore fetching data from file and writing results to disk is slow?

Answer 1

Scott Guthrie (main at Windows Azure team) to me
Hi Ivan,

We have other VM HW configurations as well – including multi-proc and high memory options. You’ll see even more options in the future.

Hope this helps,

Scott

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My test: (100% of processor time)

Lucas-Lehmer math calculations. Multithread version uses Parallel.For implementation

Home computer Core i7 3770K (4 cores x 3.5GHz) (Win 8)

SINGLETHREADED (17 primary numbers): 11676 ms (11.6 secs.)

MULTITHREADED (17 primary numbers): 2816 ms (2.8 secs.)

Azure Large VM (4 cores x 1.6 GHZ) (Win S 2008)

SINGLETHREADED (17 primary numbers): 37275 ms

MULTITHREADED 17 primary numbers): 10118 ms

Azure Extra Large VM (8 cores x 1.6 GHZ) (Win S 2008)

SINGLETHREADED (17 primary numbers): 36232 ms

MULTITHREADED (17 primary numbers): 6498 m

Work computer - AMD FX 6100 (6 cores x 3.3 Ghz) (Win 7 w upd)

SINGLETHREADED (17 primary numbers): 48758 ms

MULTITHREADED (17 primary numbers): 16486 ms

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