Re: [PATCH] sort: use posix_fadvise to announce access patterns on files opened for reading

[Joey Degges]

2010/3/2 Pádraig Brady <address@hidden>

> On 02/03/10 11:42, Erik Auerswald wrote:
>
>> Hi,
>>
>> On Mon, Mar 01, 2010 at 05:33:38PM -0800, Joey Degges wrote:
>>
>>> Were you sure to remount your devices to clear the cache before running
>>> these tests? While testing this patch early on the cache caused me many
>>> incorrect readings. Another approach I took to clear the cache was to
>>> fill
>>> up all of my RAM with some other process.
>>>
>>
>> To clear the caches you can use
>>
>> echo 3>  /proc/sys/vm/drop_caches
>>
>
> In my testing I left the inode cache alone
> for my mechanical disk and used:
>
>  echo 1 > /proc/sys/vm/drop_caches
>
> For spinning the CPU I just used:
>  openssl speed
>
> cheers,
> Pádraig.
>

Thanks for all of these suggestions. Much more elegant than what I was doing
before!

Thanks,
Joey