Ecryptfs WRITE performance issue - decryption happening

Bug #1696998 reported by venkatesh akula on 2017-06-09
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
eCryptfs
Undecided
Unassigned

Bug Description

Hi All,

We are struggling to speed up ecryptfs WRITE throughput via robocopy on samba. Our linux kernel running on ARM64 server has PAGE_SIZE of 64K.

Linux kernel version is 4.9.0 Wierd thing that we see lot of decryption happening during WRITES.

What should we tune within ecryptfs or else where - to make decryption go away ?

We expect only encryption to happen (mostly) during WRITE throughput tests.

Are there any ecryptfs patches which we can try out.

perf top

    49.50% [kernel] [k] ce_aes_cbc_encrypt
    10.37% [kernel] [k] aes_decrypt_block4x
    9.74% [kernel] [k] arch_cpu_idle
    5.42% [kernel] [k] __pi_memcpy
    3.28% [kernel] [k] ce_aes_cbc_decrypt
    1.62% [kernel] [k] md5_transform
    1.27% [kernel] [k] __arch_copy_from_user
    0.69% [kernel] [k] __pi_memset

This is not functional bug. But please help us understand the behavior why decryption is happening.

Regards
Venkat

venkatesh akula (venkatesh.cvm) wrote :

Hello Experts,

Please provide some opinion this WRITE perf problem with ecryptfs.

Appreciate your valuable suggestions.

Regards
Venkat

Jason Xing (wlxing) wrote :

Hello,

I use "perf top" to monitor the events when doing copy-command to the mounted directory. But I didn't have the decryption case. Could you provide more information?

Regards,
Jason

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