A v3 was just sent, with a fix to the algorithm used.
On 5/30/24 10:49, Pierrick Bouvier wrote:
> The goal here is to be able to scale temporally execution of qemu-user/system,
> using a given number of instructions per second.
>
> We define a virtual clock, that can be late or in advance compared to real time.
> When we are in advance, we slow execution (by sleeping) until catching real
> time.
>
> Finally, we should be able to cleanup icount=auto mode completely, and keep
> icount usage for determistic purposes only.
>
> It is built upon new TCG Plugins inline ops (store + conditional callbacks), now
> merged on master.
>
> Example in user-mode:
>
> - Retrieve number of instructions to execute /bin/true
> $ ./build/qemu-x86_64 -plugin ./build/tests/plugin/libinsn.so -d plugin /bin/true
> cpu 0 insns: 120546
> total insns: 120546
> - Slow execution to match 5 seconds
> $ time ./build/qemu-x86_64 -plugin ./build/contrib/plugins/libips,ips=$((120546/5)) /bin/true
> real 0m4.985s
>
> v2
> --
>
> - Added missing personal Signed-off-by for commits from Alex
> - Fix bad rebase in stubs/meson.build
> - move qtest_{get,set}_virtual_clock to accel/qtest/qtest.c
> - A race condition was identified for plugins init/idle/resume, but is not
> related to this series, and will be fixed in another one:
> https://lore.kernel.org/qemu-devel/20240529152219.825680-1-alex.bennee@linaro.org/
>
> Alex Bennée (4):
> sysemu: add set_virtual_time to accel ops
> qtest: use cpu interface in qtest_clock_warp
> sysemu: generalise qtest_warp_clock as qemu_clock_advance_virtual_time
> plugins: add time control API
>
> Pierrick Bouvier (2):
> qtest: move qtest_{get,set}_virtual_clock to accel/qtest/qtest.c
> contrib/plugins: add ips plugin example for cost modeling
>
> include/qemu/qemu-plugin.h | 23 ++
> include/qemu/timer.h | 15 ++
> include/sysemu/accel-ops.h | 18 +-
> include/sysemu/cpu-timers.h | 3 +-
> include/sysemu/qtest.h | 2 -
> accel/qtest/qtest.c | 13 +
> contrib/plugins/ips.c | 239 ++++++++++++++++++
> plugins/api.c | 31 +++
> ...t-virtual-clock.c => cpus-virtual-clock.c} | 5 +
> system/cpus.c | 11 +
> system/qtest.c | 37 +--
> util/qemu-timer.c | 26 ++
> contrib/plugins/Makefile | 1 +
> plugins/qemu-plugins.symbols | 2 +
> stubs/meson.build | 2 +-
> 15 files changed, 389 insertions(+), 39 deletions(-)
> create mode 100644 contrib/plugins/ips.c
> rename stubs/{cpus-get-virtual-clock.c => cpus-virtual-clock.c} (68%)
>