Re: HIGHMEM4G config for 1GB RAM on desktop?

[Miquel van Smoorenburg]

In article <41336CB1.6030105@xxxxxxxxxxxxxx>,
Timothy Miller  <miller@xxxxxxxxxxxxxx> wrote:
>Timothy Miller wrote:
>> Hey, that rings a bell.  I have a 3ware 7000-2 controller with two 
>> WD1200JB drives in RAID1.  I find that if I dd from the disk, I get 
>> exactly the read throughput that is the max for the drives (47MB/sec). 
>> However, if I do a WRITE test, the performance is miserable.
>> 
>> I have been going back and forth with 3ware for months, and what's odd 
>> is that my drives with my controller in any machine other than the 
>> primary box get great write throughput, BUT on my main box with 1G of 
>> RAM, I get MISERABLE write throughput.  When I should be getting 
>> 36MB/sec or faster, I get 8 to 12 MB/sec.
>> 
>> Now, I have tried limiting the memory with a mem= boot option, but that 
>> doesn't change the performance any.
>
>Scratch all this.  Even if I physically remove half the memory, I STILL 
>get the performance problem.

3ware eh?

Try setting /sys/block/sda/queue/nr_requests to twice the number
in /sys/block/sda/device/queue_depth

Mike.
-- 
"In times of universal deceit, telling the truth becomes
 a revolutionary act." -- George Orwell.

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