worst performance with Fc vs without when data not in cache Topic is solved

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nosiya
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worst performance with Fc vs without when data not in cache

Post by nosiya »

Hello,
I've notice a performance degradation when data is not in FC cache. Any plans to fix this problem?
An example is crystalmark, 4GB ram system virtual 64 bit pc, 1GB FC cache, no defer write or level 2 cache, 2 passes of crystalmark on a 4GB file.
Results are:
---------------With fc---------Without fc
Sequential----251/313------309/335
512kb---------24.9/54-------64/102
4kb ran-------0.85/4---------1.04/5.1
4kb(qd32)---2.1/3.2---------1.5/3.3

Excluding any fake/synthetic tests, I've done an antivirus scan of a drive (you know, the kind of thing you do or should do before doing a full backup or image), and with FC it took longer than without. 5m33 without, 8m12 with. I did reboot between each test scan. Tried a 2nd time, but the trend was still there, 6:22 without, 7:42 with.

Seems that the additional layer added by FC severely slows down the process.

Again, any plans to fix this problem?
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Re: worst performance with Fc vs without when data not in ca

Post by Support »

Does the block size match the cluster size of the partition's file system? If not, you may try it and see the result.
Here is for your reference.
http://www.romexsoftware.com/en-us/fanc ... -read.html
nosiya
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Re: worst performance with Fc vs without when data not in ca

Post by nosiya »

Hello,
I've just changes the block size = cluster size, no real difference. The pattern is still there (when data not in cache, access is slower than without FC)
I've also changed the lru/lfu-r and no particular gain/loss either.
This is done inside a vmware workstation virtual pc. Can it have a negative impact on FancyCache?
If I try it on a "real" computer (not virtual), when I choose to unistall FC, will it be completely uninstall or will there be something left over (encrypted or not registry entries , files, etc)?

Thank you.
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Re: worst performance with Fc vs without when data not in ca

Post by Support »

Thanks for the information. We'll check the performance in the virtual PCs later.
Mradr
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Re: worst performance with Fc vs without when data not in ca

Post by Mradr »

support wrote:Thanks for the information. We'll check the performance in the virtual PCs later.
Note: Use only 4GB of ram if you do with only 1GB or less of it for fancycache. I remember seeing this happen on my older system.

R/W would slow Read and Write down. Read only would only boost Read. Write Only would boost write, but also freed the hard drive for the full read speed. Long as the size of what it was writing was less than the cache ram. Other wise you would see a drop in performance altogather.
nosiya
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Re: worst performance with Fc vs without when data not in ca

Post by nosiya »

I've tested FC on a real machine (not v.m.) with 8GB and 2.5TB hd. The same pattern is present... when data is not in FC cache, it is slower than if you didn't have FC at all.
So the layer added by FC does slow down disk access. Makes sense when you think about it, it's an extra layer that the pc wastes its time going through. Still, it looks like it's too much of a performance drop.

side note: setting cluster=block (4k in this case) and 1GB level 1 cache, wastes a lot or ram. I went from 1.2GB used to 5-6GB used. I had to set block=512KB to stay about a 1GB for level 1 cache. No way I'm robing windows intelligent/proactive/dynamic cache system (prefetch, superfetch, etc) from all that ram and the big possibility of a performance drop. Will see what next version of FC does.
Thank you.
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Re: worst performance with Fc vs without when data not in ca

Post by Mradr »

nosiya wrote: side note: setting cluster=block (4k in this case) and 1GB level 1 cache, wastes a lot or ram. I went from 1.2GB used to 5-6GB used. I had to set block=512KB to stay about a 1GB for level 1 cache. No way I'm robing windows intelligent/proactive/dynamic cache system (prefetch, superfetch, etc) from all that ram and the big possibility of a performance drop. Will see what next version of FC does.
Thank you.

It's not really a bug. What you are seeing is the overhead of having smaller blocks instead of a larger block. It is sort of misleading when you can select the type of blocks. They will be changing that soon so it wont be as misleading to the user as much. ^^;
support wrote:later we'll display "overhead" value. Also we may hidden some settings such as "Block Size" for normal users to simplify the operations.
Check out here for the same issue:
viewtopic.php?f=26&t=1233

And here for what might be comming in the future:
viewtopic.php?f=26&t=1215
Note: These are community requested features and FC still holds the right/final say if they will or will not be implanted into any future releases.
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