On Tue, May 09, 2017 at 03:19:31PM +0530, Neeraj Soni wrote: > + Alasdair and dm-devel for awareness and inputs. > > On 5/9/2017 12:26 PM, Neeraj Soni wrote: > > Hi Keith/Snitzer, > > I have recently started using kernel 4.4 on a Android device and ran > Androbench to check storage read/write performance. I found that the > Random Read (RR) and Random write(RW) performance with Full Disk > Encryption is degraded compared to no Disk Encryption. Initially i > thought this must the issue with the storage part used and i compared > the performance of similar storage part on a device that was using > Android with kernel 3.18. I found that with no Disk Encryption the > performance was equivalent to the device which was using 4.4 but with > Disk Encryption there was degradation in RR (~20%) and RW(10%). > > I then tried to compare the changes that was brought in kernel 4.4 in > Full Disk Encryption path. I came across the patch mentioned in subject > and found that now a worker thread is scheduled in dm_request_fn() to > process the requests instead of directly invoking map_request() as was > in kernel 3.18. > > I reverted this patch and found that the RR and RW performance was now > closer to what we have without Disk Encryption. From the commit message > i understand that this change is significant and will be required for > blk-mq support but have you came across such degradation issue with your > patch and do we have any fix for this degradation available? Just for comparison, could you check performance on a more recent stable kernel? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
