|
+ 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?
BR,
Neeraj Soni,
--
Qualcomm Innovation Center, Inc. is
a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
|
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
