Re: [PATCH 01/11] readahead: limit readahead size for small devices

From: Wu Fengguang
Date: Thu Feb 04 2010 - 08:01:16 EST


Clemens,

Thanks for the data!

On Thu, Feb 04, 2010 at 04:24:53PM +0800, Clemens Ladisch wrote:
> Wu Fengguang wrote:
> > Anyone has 512/128MB USB stick?
>
> 64 MB, USB full speed:
> Bus 003 Device 003: ID 08ec:0011 M-Systems Flash Disk Pioneers DiskOnKey
>
> 4KB: 139.339 s, 376 kB/s
> 16KB: 81.0427 s, 647 kB/s
> 32KB: 71.8513 s, 730 kB/s
> 64KB: 67.3872 s, 778 kB/s
> 128KB: 67.5434 s, 776 kB/s
> 256KB: 65.9019 s, 796 kB/s
> 512KB: 66.2282 s, 792 kB/s
> 1024KB: 67.4632 s, 777 kB/s
> 2048KB: 69.9759 s, 749 kB/s

It seems to reach good throughput at 64KB readahead size :)

Thanks,
Fengguang
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