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

[Anna Schumaker]

On 03/26/2015 11:32 AM, Trond Myklebust wrote:
> On Thu, Mar 26, 2015 at 11:21 AM, Anna Schumaker
> <Anna.Schumaker at netapp.com> wrote:
>> Here are my updated numbers!  I tested with files 5G in size: one 100% data, one 100% hole, and one alternating between hole and data every 4K.  I collected data for both v4.1 and v4.2 with and without the READ_PLUS patches:
>>
>> ##########################
>> #                        #
>> #   Without READ_PLUS    #
>> #                        #
>> ##########################
>>
>>
>> NFS v4.1:
>>                             Trial
>> |---------|---------|---------|---------|---------|---------|---------|
>> |         |    1    |    2    |    3    |    4    |    5    | Average |
>> |---------|---------|---------|---------|---------|---------|---------|
>> |    Data |  8.723s |  7.243s |  8.252s |  6.997s |  6.980s |  7.639s |
>> |    Hole |  5.271s |  5.224s |  5.060s |  4.897s |  5.321s |  5.155s |
>> |   Mixed |  8.050s | 10.057s |  7.919s |  8.060s |  9.557s |  8.729s |
>> |---------|---------|---------|---------|---------|---------|---------|
>>
>>
>>
>>
>> NFS v4.2:
>>                             Trial
>> |---------|---------|---------|---------|---------|---------|---------|
>> |         |    1    |    2    |    3    |    4    |    5    | Average |
>> |---------|---------|---------|---------|---------|---------|---------|
>> |    Data |  6.707s |  7.070s |  6.722s |  6.761s |  6.810s |  6.814s |
>> |    Hole |  5.152s |  5.149s |  5.213s |  5.206s |  5.312s |  5.206s |
>> |   Mixed |  7.979s |  7.985s |  8.177s |  7.772s |  8.280s |  8.039s |
>> |---------|---------|---------|---------|---------|---------|---------|
>>
>>
>>
>>
>>
>> #######################
>> #                     #
>> #   With READ_PLUS    #
>> #                     #
>> #######################
>>
>>
>> NFS v4.1:
>>                             Trial
>> |---------|---------|---------|---------|---------|---------|---------|
>> |         |    1    |    2    |    3    |    4    |    5    | Average |
>> |---------|---------|---------|---------|---------|---------|---------|
>> |    Data |  9.082s |  7.008s |  7.116s |  6.771s |  7.902s |  7.576s |
>> |    Hole |  5.333s |  5.358s |  5.380s |  5.161s |  5.282s |  5.303s |
>> |   Mixed |  8.189s |  8.308s |  9.540s |  7.937s |  8.420s |  8.479s |
>> |---------|---------|---------|---------|---------|---------|---------|
>>
>>
>>
>>
>> NFS v4.2:
>>                             Trial
>> |---------|---------|---------|---------|---------|---------|---------|
>> |         |    1    |    2    |    3    |    4    |    5    | Average |
>> |---------|---------|---------|---------|---------|---------|---------|
>> |    Data |  7.033s |  6.829s |  7.025s |  6.873s |  7.134s |  6.979s |
>> |    Hole |  1.794s |  1.800s |  1.905s |  1.811s |  1.725s |  1.807s |
>> |   Mixed |  7.590s |  8.777s |  9.423s | 10.366s |  8.024s |  8.836s |
>> |---------|---------|---------|---------|---------|---------|---------|
>>
> 
> So there is a clear win in the 100% hole case here, but otherwise the
> statistical fluctuations are dominating the numbers. Can you get us a
> little more stats and then perhaps run the results through nfsometer?

Sure!  Do you want any information besides runtime?

Anna

> 
>>
>>
>> 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.
>>>
>>
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> 
> 
>