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* Bad performance since 5.9-rc1
@ 2020-11-19  3:05 Zdenek Kaspar
  2020-12-01  6:35 ` Zdenek Kaspar
  2020-12-02  0:31 ` Sean Christopherson
  0 siblings, 2 replies; 11+ messages in thread
From: Zdenek Kaspar @ 2020-11-19  3:05 UTC (permalink / raw)
  To: kvm

Hi,

in my initial report (https://marc.info/?l=kvm&m=160502183220080&w=2 -
now fixed by c887c9b9ca62c051d339b1c7b796edf2724029ed) I saw degraded
performance going back somewhere between v5.8 - v5.9-rc1.

OpenBSD 6.8 (GENERIC.MP) guest performance (time ./test-build.sh)
good: 0m13.54s real     0m10.51s user     0m10.96s system
bad : 6m20.07s real    11m42.93s user     0m13.57s system

bisected to first bad commit: 6b82ef2c9cf18a48726e4bb359aa9014632f6466

git bisect log:
# bad: [e47c4aee5bde03e7018f4fde45ba21028a8f8438] KVM: x86/mmu: Rename
page_header() to to_shadow_page() # good:
[01c3b2b5cdae39af8dfcf6e40fdf484ae0e812c5] KVM: SVM: Rename
svm_nested_virtualize_tpr() to nested_svm_virtualize_tpr() git bisect
start 'e47c4aee5bde' '01c3b2b5cdae' # bad:
[ebdb292dac7993425c8e31e2c21c9978e914a676] KVM: x86/mmu: Batch zap MMU
pages when shrinking the slab git bisect bad
ebdb292dac7993425c8e31e2c21c9978e914a676 # good:
[fb58a9c345f645f1774dcf6a36fda169253008ae] KVM: x86/mmu: Optimize MMU
page cache lookup for fully direct MMUs git bisect good
fb58a9c345f645f1774dcf6a36fda169253008ae # bad:
[6b82ef2c9cf18a48726e4bb359aa9014632f6466] KVM: x86/mmu: Batch zap MMU
pages when recycling oldest pages git bisect bad
6b82ef2c9cf18a48726e4bb359aa9014632f6466 # good:
[f95eec9bed76d42194c23153cb1cc8f186bf91cb] KVM: x86/mmu: Don't put
invalid SPs back on the list of active pages git bisect good
f95eec9bed76d42194c23153cb1cc8f186bf91cb # first bad commit:
[6b82ef2c9cf18a48726e4bb359aa9014632f6466] KVM: x86/mmu: Batch zap MMU
pages when recycling oldest pages

Host machine is old Intel Core2 without EPT (TDP).

TIA, Z.

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2021-01-13 22:22 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-19  3:05 Bad performance since 5.9-rc1 Zdenek Kaspar
2020-12-01  6:35 ` Zdenek Kaspar
2020-12-18 19:33   ` Zdenek Kaspar
2020-12-21 19:41     ` Sean Christopherson
2020-12-21 21:13       ` Zdenek Kaspar
2020-12-22 17:07         ` Sean Christopherson
2020-12-22 21:26           ` Zdenek Kaspar
2021-01-12 11:18             ` Zdenek Kaspar
2021-01-13 20:17               ` Sean Christopherson
2021-01-13 22:17                 ` Zdenek Kaspar
2020-12-02  0:31 ` Sean Christopherson

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