This is the third iteration of the RFC patch set which aims to provide the basic framework for MTTCG. There have been some considerable changes since the last extensive review (thanks to all the reviewers).
- many updates to docs/multi-thread-tcg.txt design document - added assertions for all the locking requirements - split apart the big enable thread-per-vCPU patch - removed locking from the hot-path In general the main thread functions are a lot less messy (especially the single thread variant). The splitting apart of the big enabling patch was helped by removing tcg_current_cpu and the global exit_request as separate patches. Finally the big performance boost of a lockless hot-path is made possible by Emilio's QHT work which this is based on. The branch can be found at: https://github.com/stsquad/qemu/tree/mttcg/base-patches-v3 It has been built up on top of: https://github.com/stsquad/qemu/tree/review/qht-v6 What's next =========== This series should now behave as normal in the default single threaded mode and in multi-threaded mode where SMP==1. Please report any regressions/bugs you find. multi-threaded mode works for any guests that don't make assumptions about atomicity, memory consistency or cache flushes. Basically simple kvm-unit-test cases. I've been using the simple locking-test: ./arm/run ./arm/locking-test.flat -smp 4 -accel tcg,thread=[single|multi] Default: real 0m14.804s user 0m14.752s sys 0m0.032s Multi-threaded: real 0m6.307s user 0m23.396s sys 0m0.020s With the lockless hot-path (thanks QHT ;-) we can now see a benefit in running with multiple threads with a slight cost to overall CPU time. I intend to run a more complete set of benchmarks once I'm re-based by ARM specific series on top of this patch-set (and compared the LL/SC work with the simple lock based exclusives in the original series.) In the meantime any review comments gratefully received. Cheers, Alex Alex Bennée (15): cpus: make all_vcpus_paused() return bool translate_all: DEBUG_FLUSH -> DEBUG_TB_FLUSH translate-all: add DEBUG_LOCKING asserts docs: new design document multi-thread-tcg.txt (DRAFTING) exec: add assert_debug_safe and notes on debug structures translate-all: Add assert_memory_lock annotations target-arm/arm-powerctl: wake up sleeping CPUs tcg: cpus rm tcg_exec_all() tcg: add kick timer for single-threaded vCPU emulation tcg: rename tcg_current_cpu to tcg_current_rr_cpu tcg: remove global exit_request tcg: drop global lock during TCG code execution tcg: move locking for tb_invalidate_phys_page_range up tcg: enable thread-per-vCPU cpu-exec: remove tb_lock from the hot-path KONRAD Frederic (2): tcg: protect TBContext with tb_lock. tcg: add options for enabling MTTCG Paolo Bonzini (1): tcg: comment on which functions have to be called with tb_lock held Sergey Fedorov (1): tcg: Ensure safe TB lookup out of 'tb_lock' bsd-user/mmap.c | 5 + cpu-exec-common.c | 3 - cpu-exec.c | 104 ++++++----- cpus.c | 448 ++++++++++++++++++++++++++++------------------ cputlb.c | 1 + docs/multi-thread-tcg.txt | 225 +++++++++++++++++++++++ exec.c | 87 ++++++++- hw/i386/kvmvapic.c | 4 + include/exec/exec-all.h | 6 +- include/qom/cpu.h | 11 ++ include/sysemu/cpus.h | 2 + linux-user/elfload.c | 4 + linux-user/main.c | 1 + linux-user/mmap.c | 5 + memory.c | 2 + qemu-options.hx | 20 +++ softmmu_template.h | 17 ++ target-arm/Makefile.objs | 2 +- target-arm/arm-powerctl.c | 2 + target-i386/smm_helper.c | 7 + tcg/tcg.h | 2 + translate-all.c | 187 +++++++++++++++---- vl.c | 45 ++++- 23 files changed, 931 insertions(+), 259 deletions(-) create mode 100644 docs/multi-thread-tcg.txt -- 2.7.4
