Hi

Post kernel 4.9, I am experiencing more than 50% degrade in ipsec performance 
on my arm64 based systems (with onchip crypto accelerator).
(We use only lts kernels). My understanding is that it is mainly due to xfrm 
flow cache removal in version 4.12.

I am not sure whether any subsequent work could recover the lost performance.
With kernel 4.19, I see that xfrm_state_find() is taking a lot of cpu (more 
than 15%).
Further, perf show that a lot of atomic primitives such as 
__ll_sc___cmpxchg_case_mb_4(), 
__ll_sc_atomic_sub_return() are being invoked. On 16 core system, they consume 
more than 30% of cpu.

These are getting called mainly from xfrm_lookup_with_ifid().

Can someone please help?

Regards

Vakul

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