figured out the real reason why this is so slow poking around in gdb some more. kvm_log_clear iterates kvm_state->nr_slots times clearing out dirty bitmaps on each memory slot. the code seems to assume nr_slots is relatively small - 32 is the default value for it if KVM_CAP_NR_MEMSLOTS is unspecified.
on my machine, KVM_CAP_NR_MEMSLOTS is 32764 :)
tracking down this mismatch between assumption and reality has led me to find it's been fixed already upstream. neat! https://patchew.org/QEMU/20230421032522.999-1-robert.hoo.linux@gmail.com/
Hailey
npub1qr…9shcs
2024-11-24 13:03:09 UTC
in reply to nevent1q…9guv
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npub1qrutk0v9kq82u2hd8k62zemyyx3mf0sfrcvj5xeec4axnk2vj5psu9shcsSeen on
wss://relay.momostr.pinkPublished at
2024-11-24 13:03:09 UTCEvent JSON
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"content": "figured out the real reason why this is so slow poking around in gdb some more. kvm_log_clear iterates kvm_state-\u003enr_slots times clearing out dirty bitmaps on each memory slot. the code seems to assume nr_slots is relatively small - 32 is the default value for it if KVM_CAP_NR_MEMSLOTS is unspecified.\n\non my machine, KVM_CAP_NR_MEMSLOTS is 32764 :)\n\ntracking down this mismatch between assumption and reality has led me to find it's been fixed already upstream. neat! https://patchew.org/QEMU/20230421032522.999-1-robert.hoo.linux@gmail.com/",
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