# 31 -> 32,32 Disk Throughput Regression?

## gqman69

So I have this new OCZ Vertex Turbo (30GB) SSD Hard drive and it works amazing.

But this is my problem, with kernel 2.6.31 everything work good,

hdparm -Tt, piozone, iozone, bonnie++ all gives me 215-230MB/s reads

and 140-170MB/s writes.

Using 2.6.32 things get ugly... Using the exact config, absolutely no change I get

100MB/s read and 80MB/s writes.

Now with 2.6.33_rcX I get even worse 78MB/s reads...

Yes I tried different schedulers, cfq is the best by far.

My question is WTH?

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## gqman69

This is what I got:

```

[    2.653505] ata1: SATA max UDMA/133 abar m2048@0xf3ffc000 port 0xf3ffc100 irq 33

[    3.071424] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)

[    3.071607] ata1.00: ATA-8: OCZ VERTEX-TURBO, 1.4, max UDMA/133

[    3.071609] ata1.00: 62533296 sectors, multi 1: LBA48 NCQ (depth 31/32), AA

[    3.073328] ata1.00: configured for UDMA/133

```

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## cach0rr0

Wonder if perhaps this is relevant

http://www.phoronix.com/scan.php?page=news_item&px=Nzc5NA

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## gqman69

It's is possible, but doesn't hdparm -Tt and piozone use block read and not the underlying filesystem?

It doesn't really explain the results of my second hard drive which is also EXT4 and which is not an SSD.

It gets steady 100MB/s to 80MB/s in a linear fashion with all kernels.

This is weird.

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## cach0rr0

 *gqman69 wrote:*   

> It's is possible, but doesn't hdparm -Tt and piozone use block read and not the underlying filesystem?
> 
> It doesn't really explain the results of my second hard drive which is also EXT4 and which is not an SSD.
> 
> It gets steady 100MB/s to 80MB/s in a linear fashion with all kernels.
> ...

 

you're quite right about hdparm, and in my haste to respond I completely overlooked that - sorry about that. 

I just read the title and remembered "hey yeah, i remember reading something about that on Phoronix"

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## gqman69

So I tried zen-sources 2.6.32 with the BFQ scheduler...

I now get 130-140MB/s read with burst up to 180MB/s.

So this seems to be related to the scheduler.

It does somewhat confirm this article: http://www.linux-mag.com/id/7637

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