On 2024/4/21 21:53, Peter Xu wrote:
On Sat, Apr 20, 2024 at 12:05:04PM +0800, Kefeng Wang wrote:The latency of lat_pagefault increased a lot than the old kernel(vs 5.10), except mm counter updating, the another obvious difference shown from perf graph is the new vmf_orig_pte_uffd_wp().Curious how different it is.
It is not big, as shown in perf, only 0.1x% in the whole test, but it is new added compared with old kernel. Please check attached perf_0417_pagefault_x86.svg [with batch mm counter],
I wanted to give it a quick shot over lmbench but fails on missing rpc.h, at least for the Intel repo. I think it's because of the libc change to drop that. Are you using a separate repo that fixed all things up?
yum install libtirpc-devel, I can build with it.
Moving it upper is better, and maybe add __always_inline to vmf_orig_pte_uffd_wp() to make set_pte_range() only check VM_UFFD_WP from vm_flags?Sounds good here, thanks.
OK, will update it too. Thanks.
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perf_0417_pagefault_x86.svg
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