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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-06-30 12:24:58 +0000 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-06-30 12:27:06 +0000 |
| commit | 33606b41d35115f887ea688b1a16f2ff85bf2fe4 (patch) | |
| tree | 406b2c7b19a087ba437c68f3dbf0b589fa1d6150 /results/scraper/launchpad-without-comments/1912777 | |
| parent | adedf8771bc4de3113041ca21bd4d0d1c0014b6a (diff) | |
| download | emulator-bug-study-33606b41d35115f887ea688b1a16f2ff85bf2fe4.tar.gz emulator-bug-study-33606b41d35115f887ea688b1a16f2ff85bf2fe4.zip | |
add launchpad bug reports without comments
Diffstat (limited to 'results/scraper/launchpad-without-comments/1912777')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1912777 | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1912777 b/results/scraper/launchpad-without-comments/1912777 new file mode 100644 index 00000000..fe8af7f1 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1912777 @@ -0,0 +1,95 @@ +KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0 + +I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0 +From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution. + +I executed same testcase from Qemu 2.11 and Qemu4. +Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds +but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds. + + +I did a bit of digging and extracted the kvm_run_exit to figure out whats going on. + +Please find +Stats from Qemu2.11: + +KVM_EXIT_UNKNOWN : 0 +KVM_EXIT_EXCEPTION : 0 +KVM_EXIT_IO : 182513 +KVM_EXIT_HYPERCALL : 0 +KVM_EXIT_DEBUG : 0 +KVM_EXIT_HLT : 0 +KVM_EXIT_MMIO : 216701 +KVM_EXIT_IRQ_WINDOW_OPEN : 0 +KVM_EXIT_SHUTDOWN : 0 +KVM_EXIT_FAIL_ENTRY : 0 +KVM_EXIT_INTR : 0 +KVM_EXIT_SET_TPR : 0 +KVM_EXIT_TPR_ACCESS : 0 +KVM_EXIT_S390_SIEIC : 0 +KVM_EXIT_S390_RESET : 0 +KVM_EXIT_DCR : 0 +KVM_EXIT_NMI : 0 +KVM_EXIT_INTERNAL_ERROR : 0 +KVM_EXIT_OSI : 0 +KVM_EXIT_PAPR_HCALL : 0 +KVM_EXIT_S390_UCONTROL : 0 +KVM_EXIT_WATCHDOG : 0 +KVM_EXIT_S390_TSCH : 0 +KVM_EXIT_EPR : 0 +KVM_EXIT_SYSTEM_EVENT : 0 +KVM_EXIT_S390_STSI : 0 +KVM_EXIT_IOAPIC_EOI : 0 +KVM_EXIT_HYPERV : 0 + +KVM_RUN_EXIT : 399214 (Total in Qemu 2.11 for a testcase) + + +Stats For Qemu 4.0.0: + +VM_EXIT_UNKNOWN : 0 +KVM_EXIT_EXCEPTION : 0 +KVM_EXIT_IO : 163729 +KVM_EXIT_HYPERCALL : 0 +KVM_EXIT_DEBUG : 0 +KVM_EXIT_HLT : 0 +KVM_EXIT_MMIO : 1094231 +KVM_EXIT_IRQ_WINDOW_OPEN : 46 +KVM_EXIT_SHUTDOWN : 0 +KVM_EXIT_FAIL_ENTRY : 0 +KVM_EXIT_INTR : 0 +KVM_EXIT_SET_TPR : 0 +KVM_EXIT_TPR_ACCESS : 0 +KVM_EXIT_S390_SIEIC : 0 +KVM_EXIT_S390_RESET : 0 +KVM_EXIT_DCR : 0 +KVM_EXIT_NMI : 0 +KVM_EXIT_INTERNAL_ERROR : 0 +KVM_EXIT_OSI : 0 +KVM_EXIT_PAPR_HCALL : 0 +KVM_EXIT_S390_UCONTROL : 0 +KVM_EXIT_WATCHDOG : 0 +KVM_EXIT_S390_TSCH : 0 +KVM_EXIT_EPR : 0 +KVM_EXIT_SYSTEM_EVENT : 0 +KVM_EXIT_S390_STSI : 0 +KVM_EXIT_IOAPIC_EOI : 464 +KVM_EXIT_HYPERV : 0 + +KVM_RUN_EXIT : 1258470 (Total in qemu 4.0.0 for same testcase) + + + +From above analysis i found that the number of KVM_EXIT_MMIO has increased by 4.x. + +Could someone from qemu community help me understand as to why the MMIO exits have increased in qemu4 ? + +The results i obtained are after running same testcase. +On Qemu2.11 testcase gets completed in : 11seconds +on Qemu4.11 testcase gets completed in : 26 seconds + +VM Qcow2 used in Ubuntu 16.04 +VM kernel OS is : 4.4 generic + + +Let me know incase more information is required . \ No newline at end of file |