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Re: hibernate: swap on SSD = not fast

On 24/08/12 08:29 AM, Gaël DONVAL wrote:

Le vendredi 24 août 2012 à 12:58 +0100, Darac Marjal a écrit :

On Fri, Aug 24, 2012 at 01:32:16PM +0200, Gaël DONVAL wrote:

Le vendredi 24 août 2012 à 12:04 +0100, Darac Marjal a écrit :

I might be wrong here, but isn't the key benefit of SSDs that they have
a tiny access time? But that their read speed is about the same as a
normal disk (also, I might be wrong, but I understand their write speed
is average).

This would have been true some years ago:

Comparison of average sequential reading rates (HDD of 2012 and SSD of
2011):
http://www.tomshardware.com/charts/ssd-charts-2011/AS-SSD-Sequential-Read,2782.html
http://www.tomshardware.com/charts/hdd-charts-2012/-01-Read-Throughput-Average-h2benchw-3.16,2901.html

Please note that I compared SSD with desktop HDD: mobile HDDs are
generally slower.

About write speed, the very best HDD gave 164.06MB/s on average while
*most* SSDs are above 150MB/s and the best reaches a few MB/s less than
400.

Ah, my knowledge was out of date. I'll try and squirrel away that
factoid :)


:)
But you comment still holds true: one should not expect a huge increase
of performance here as far as hibernation is concerned.
For a fast hibernate, sequential write speed is the key benchmark. The Samsung 830 is supposedly very fast at this. However, the original poster complained that hibernation is actually slower. This is the issue that should be discussed.
So why would switching to an SSD slow hibernation times? Frankly I can't think of any reasons (comparing apples to apples) why a faster drive should lead to slower performance. Possibly it's an interface issue - the SSD's controller is getting swamped - while the HDD the poster had been using was able to handle a faster continuous write. 

However, I can't find any evidence for this in the TomsHardware benchmarks.
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