Re: [PATCH v3 3/3] NFSD: Add support for encoding multiple segments

Anna Schumaker
2015-03-25T17:15:14Z

On 03/24/2015 01:49 PM, Christoph Hellwig wrote:
> On Tue, Mar 24, 2015 at 08:43:31AM -0400, Anna Schumaker wrote:
>>> I don't know, and don't have profiles. I'll either try to reproduce or
>>> wait till Anna's back from vacation.
>>
>> I'm using whatever functions NFSD already uses for reading files,
>> which I expect go through the VFS. Is there a flag that controls
>> cache behavior?
>
> There's the O_DIRECT flag, but that's not what I mean. If you just
> wrote to it it's a cached read, if you did unmount the filesystem after
> writing, or did an echo to /proc/sys/vm/drop_caches you get uncached
> read behavior.

Oh, I'm doing uncached reads for my tests. I'm collecting updated numbers now!

Anna