Re: Minutes from 10/1 LSE Call

[Andrew Morton]

insecure <insecure@xxxxxxxxxx> wrote:
>
> So:
>  * we hit a ceiling of ~133 Mb/s, no matter how many disks
>  * CPU utilization is 100%, spent mostly in copy_to_user
>  * RAM bandwidth is >1Gb/s
> 
>  These can't be true at once.

True.  But bear in mind that the data crosses the memory busses up to three
times: disk to pagecache, pagecache to CPU, CPU to user memory.

So top speed may be as little as 300 MB/sec.


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