v2: - Added two more patches (patch 4&5) to add the checkpoints too, it means it merges Joao's series into tracepoints, and extend that to dest QEMU. - Patch 5: Prefixed checkpoints with "src-" and "dst-"
This small series wants to improve ability of QEMU downtime analysis similarly to what Joao used to propose here: https://lore.kernel.org/r/20230926161841.98464-1-joao.m.mart...@oracle.com But with a few enhancements: - Nothing exported yet to qapi, all tracepoints so far - Besides major checkpoints, finer granule by providing downtime measurements for each vmstate (I made microsecond to be the unit to be accurate) alongside. - Trace dest QEMU too for either the checkpoints or vmsd load()s For the last bullet: consider the case where a device save() can be super fast, while load() can actually be super slow. Both of them will contribute to the ultimate downtime, but not a simple addition: when src QEMU is save()ing on device1, dst QEMU can logically be load()ing on device2. So they can run in parallel. However the only way to figure all components of the downtime is to record both. Please have a look, thanks. Peter Xu (5): migration: Set downtime_start even for postcopy migration: Add migration_downtime_start|end() helpers migration: Add per vmstate downtime tracepoints migration: migration_stop_vm() helper migration: Add tracepoints for downtime checkpoints migration/migration.h | 2 ++ migration/migration.c | 63 +++++++++++++++++++++++++++++++----------- migration/savevm.c | 63 ++++++++++++++++++++++++++++++++++++------ migration/trace-events | 4 ++- 4 files changed, 106 insertions(+), 26 deletions(-) -- 2.41.0
