Re: stochastic fair queueing in the elevator [Re: [BENCHMARK] 2.4.20-ck3 / aa / rmap with contest]

Nick Piggin
2003-02-10T12:05:08Z

Andrea Arcangeli wrote:

>On Mon, Feb 10, 2003 at 10:53:27PM +1100, Nick Piggin wrote:
>
>>Andrew Morton wrote:
>>
>>
>>>Andrea Arcangeli <andrea@suse.de> wrote:
>>>
>>>
>>>>It's the readahead in my tree that allows the reads to use the max scsi
>>>>command size. It has nothing to do with the max scsi command size
>>>>itself.
>>>>
>>>>
>>>Oh bah.
>>>
>>>- *max_ra++ = vm_max_readahead;
>>>+ *max_ra = ((128*4) >> (PAGE_SHIFT - 10)) - 1;
>>>
>>>
>>>Well of course that will get bigger bonnie numbers, for exactly the reasons
>>>I've explained. It will seek between files after every 512k rather than
>>>after every 128k.
>>>
>>>
>>Though Andrea did say it is a "single threaded" streaming read.
>>
>
>yes, I pointed you to bonnie read sequential in bigbox.html, not
>tiobench.
>
The same pattern is also observed with single threaded tiobench
anyway.