On Fri, Mar 27, 2015 at 04:55:26PM -0400, Anna Schumaker wrote: > On 03/27/2015 04:54 PM, J. Bruce Fields wrote: > > On Fri, Mar 27, 2015 at 04:46:55PM -0400, Anna Schumaker wrote: > >> On 03/27/2015 04:22 PM, Trond Myklebust wrote: > >>> On Fri, Mar 27, 2015 at 3:04 PM, Anna Schumaker > >>> <Anna.Schumaker@xxxxxxxxxx> wrote: > >>>> I did two separate dd tests with the same 5G file from yesterday, and still using the same virtual machines. First, I ran dd using direct IO for reads: > >>>> dd if=/nfs/file iflag=direct of=/dev/null bs=128K > >>>> > >>>> Mixed file performance was awful, so I reran without direct IO enabled for comparison: > >>>> dd if=/nfs/file iflag=nocache of=/dev/null oflag=nocache bs=128K > >>>> > >>>> bs=128K sets the block size used by dd to the NFS rsize, without this dd will only read 512 bytes at a time and take forever to complete. > >>>> > >>>> > >>>> ########################## > >>>> # # > >>>> # Without READ_PLUS # > >>>> # # > >>>> ########################## > >>>> > >>>> > >>>> NFS v4.1, iflag=direct: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 11.704s | 11.055s | 11.329s | 11.453s | 10.741s | 11.256s | > >>>> | Hole | 9.839s | 9.326s | 9.381s | 9.430s | 8.875s | 9.370s | > >>>> | Mixed | 19.150s | 19.468s | 18.650s | 18.537s | 19.312s | 19.023s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> NFS v4.2, iflag=direct: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 10.927s | 10.885s | 11.114s | 11.283s | 10.371s | 10.916s | > >>>> | Hole | 9.515s | 9.039s | 9.116s | 8.867s | 8.905s | 9.088s | > >>>> | Mixed | 19.149s | 18.656s | 19.400s | 18.834s | 20.041s | 19.216s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> > >>>> > >>>> NFS v4.1, iflag=nocache oflag=nocache: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 6.808s | 6.698s | 7.482s | 6.761s | 7.235s | 6.995s | > >>>> | Hole | 5.350s | 5.148s | 5.161s | 5.070s | 5.089s | 5.164s | > >>>> | Mixed | 9.316s | 8.731s | 9.072s | 9.145s | 8.627s | 8.978s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> NFS v4.2, iflag=nocache oflag=nocache: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 6.686s | 6.848s | 6.876s | 6.799s | 7.815s | 7.004s | > >>>> | Hole | 5.092s | 5.330s | 5.050s | 5.280s | 5.030s | 5.156s | > >>>> | Mixed | 8.142s | 7.897s | 8.040s | 7.960s | 8.050s | 8.018s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> ####################### > >>>> # # > >>>> # With READ_PLUS # > >>>> # # > >>>> ####################### > >>>> > >>>> > >>>> NFS v4.1, iflag=direct: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 9.464s | 10.181s | 10.048s | 9.452s | 10.795s | 9.988s | > >>>> | Hole | 7.954s | 8.486s | 7.762s | 7.969s | 8.299s | 8.094s | > >>>> | Mixed | 19.037s | 18.323s | 18.965s | 18.156s | 19.185s | 18.733s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> NFS v4.2, iflag=direct: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 11.923s | 10.026s | 10.222s | 12.387s | 11.431s | 11.198s | > >>>> | Hole | 3.247s | 3.155s | 3.191s | 3.243s | 3.202s | 3.208s | > >>>> | Mixed | 54.677s | 54.697s | 52.978s | 53.704s | 54.054s | 54.022s | > >>> > >>> That's a bit nasty. Any idea what is going on with the Mixed case here? > >> > >> Not offhand, but my first guess would be something to do with extra seeks to find how long each hole and data segment is. > > > > Remind us what "mixed" means? (I think you were alternating, but how > > large is each segment?) > > "Mixed" is alternating 4K segments. So it's probably doing 128/4 = 32 reads where previously one was necessary. You could confirm that by looking at the READ counts in /proc/self/mountstats. With odirect turned off maybe that's hidden by readahead? --b. > > > > > --b. > > > >> > >> Anna > >> > >>> > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> > >>>> > >>>> NFS v4.1, iflag=nocache oflag=nocache: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 6.788s | 6.802s | 6.750s | 6.756s | 6.852s | 6.790s | > >>>> | Hole | 5.143s | 5.165s | 5.104s | 5.154s | 5.116s | 5.136s | > >>>> | Mixed | 7.902s | 7.693s | 9.169s | 8.186s | 9.157s | 8.421s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> NFS v4.2, iflag=nocache oflag=nocache: > >>>> Trial > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | | 1 | 2 | 3 | 4 | 5 | Average | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> | Data | 6.897s | 6.862s | 7.054s | 6.961s | 7.081s | 6.971s | > >>>> | Hole | 1.690s | 1.673s | 1.553s | 1.554s | 1.490s | 1.592s | > >>>> | Mixed | 9.009s | 7.840s | 7.661s | 8.945s | 7.649s | 8.221s | > >>>> |---------|---------|---------|---------|---------|---------|---------| > >>>> > >>>> > >>>> On 03/26/2015 12:13 PM, Trond Myklebust wrote: > >>>>> On Thu, Mar 26, 2015 at 12:11 PM, Anna Schumaker > >>>>> <Anna.Schumaker@xxxxxxxxxx> wrote: > >>>>>> On 03/26/2015 12:06 PM, Trond Myklebust wrote: > >>>>>>> On Thu, Mar 26, 2015 at 11:47 AM, Anna Schumaker > >>>>>>> <Anna.Schumaker@xxxxxxxxxx> wrote: > >>>>>>>> On 03/26/2015 11:38 AM, J. Bruce Fields wrote: > >>>>>>>>> On Thu, Mar 26, 2015 at 11:32:25AM -0400, Trond Myklebust wrote: > >>>>>>>>>> On Thu, Mar 26, 2015 at 11:21 AM, Anna Schumaker > >>>>>>>>>> <Anna.Schumaker@xxxxxxxxxx> 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? > >>>>>>>>> > >>>>>>>>> Also, could you describe the setup (are these still kvm's), and how > >>>>>>>>> you're clearing the cache between runs? > >>>>>>>> > >>>>>>>> These are still KVMs and my server is exporting an xfs filesystem. I clear caches by running "echo 3 > /proc/sys/vm/drop_caches" on the server before every read, and I remount my client after reading each set of three files once. > >>>>>>> > >>>>>>> I agree that you have to use the 'drop_caches' interface on the > >>>>>>> server, but why not just use O_DIRECT on the clients? > >>>>>> > >>>>>> I've been reading by using cat from my test shell script: `time cat /nfs/file > /dev/null`. I can write something to read files with O_DIRECT if that would be more useful! > >>>>>> > >>>>> > >>>>> 'dd' can do that for you if the appropriate incantations are performed. > >>>>> > >>>> > >>>> -- > >>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx > >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > >>> > >>> > >>> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
