These patches add ability to measure speed of MMIO versus PIO, in
different configurations. As I didn't want to reserve a hardcoded range
of memory, I added pci bus scan support instead. Used together with the
new pci-testdev backend. When not present, the new tests are skipped.
Example output:
mmio-no-eventfd:pci-mem 8796
mmio-wildcard-eventfd:pci-mem 3609
mmio-datamatch-eventfd:pci-mem 3685
portio-no-eventfd:pci-io 5287
portio-wildcard-eventfd:pci-io 1762
portio-datamatch-eventfd:pci-io 1777
First interesting conclusion is that the overhead of MMIO
exit to QEMU as compared to PIO is double that of
MMIO ioeventfd as compared to PIO eventfd. Is this a known fact?
Michael S. Tsirkin (5):
kvm-unittest: add printf %c support
kvm-unittest: libcflat: add offsetof
libcflat.h: define NULL
lib: add pci bus scan support
vmexit: add pci io and memory speed tests
config-x86-common.mak | 1 +
lib/libcflat.h | 3 +
lib/printf.c | 3 +
lib/x86/pci.c | 55 ++++++++++++
lib/x86/pci.h | 16 ++++
x86-run | 13 ++-
x86/vmexit.c | 226 +++++++++++++++++++++++++++++++++++++++++++++++---
7 files changed, 302 insertions(+), 15 deletions(-)
create mode 100644 lib/x86/pci.c
create mode 100644 lib/x86/pci.h
--
MST
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