Re: [PATCH v8 00/74] per-CPU locks

[Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>]

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21:37 Čet, 26.03.2020. Robert Foley <robert.foley@linaro.org> је написао/ла:
>
> V7: https://lists.gnu.org/archive/html/qemu-devel/2019-03/msg00786.html
>
> This is a continuation of the series created by Emilio Cota.
> We are picking up this patch set with the goal to apply
> any fixes or updates needed to get this accepted.
>

Thank for this work, Robert.

However, I just hope you don't intend to request integrating the series in
5.0. The right timing for such wide-influencing patch is at the begining of
dev cycle, not really at the end of (5.0) cycle, IMHO.

Yours,
Aleksandar

> Quoting an earlier patch in the series:
> "For context, the goal of this series is to substitute the BQL for the
> per-CPU locks in many places, notably the execution loop in cpus.c.
> This leads to better scalability for MTTCG, since CPUs don't have
> to acquire a contended global lock (the BQL) every time they
> stop executing code.
> See the last commit for some performance numbers."
>
> Listed below are the changes for this version of the patch,
> aside from the merge related changes.
>
> Changes for V8:
> - Fixed issue where in rr mode we could destroy the BQL twice.
>   Added new function cpu_mutex_destroy().
> - Removed g_assert(qemu_mutex_iothread_locked())
>   from qemu_tcg_rr_all_cpu_threads_idle().  There is an existing
>   case where we call qemu_tcg_rr_all_cpu_threads_idle() without
>   the BQL held, so we cannot assert on the lock here.
> - Found/fixed bug that had been hit in testing previously during
>   the last consideration of this patch.
>   We reproduced the issue hit in the qtest: bios-tables-test.
>   The issue was introduced by dropping the BQL, and found us
>   (very rarely) missing the condition variable wakeup in
>   qemu_tcg_rr_cpu_thread_fn().
> - ppc: convert to cpu_halted
>   - Converted new code for cpu_halted and cpu_halted_set.
> - hw/semihosting: convert to cpu_halted_set
>   -  Added this patch as this code was new and needed converting.
> - ppc/translate_init.inc.c
>   - Translated some new code here to use cpu_has_work_with_iothread_lock.
> - ppc/sapr_hcall.c Translated new code to cpu_halted
> - i386/hax-all.c - converted new code to cpu_interrupt_request and
cpu_halted
> - mips/kvm.c - converted new code to cpu_halted
> - Some changes were related to files that moved, cpu.c and cpu.h
>   moved to hw/core/, and some changes needed to be put
>   there manually during the merge.
>
> Emilio G. Cota (69):
>   cpu: convert queued work to a QSIMPLEQ
>   cpu: rename cpu->work_mutex to cpu->lock
>   cpu: introduce cpu_mutex_lock/unlock
>   cpu: make qemu_work_cond per-cpu
>   cpu: move run_on_cpu to cpus-common
>   cpu: introduce process_queued_cpu_work_locked
>   cpu: make per-CPU locks an alias of the BQL in TCG rr mode
>   tcg-runtime: define helper_cpu_halted_set
>   ppc: convert to helper_cpu_halted_set
>   cris: convert to helper_cpu_halted_set
>   hppa: convert to helper_cpu_halted_set
>   m68k: convert to helper_cpu_halted_set
>   alpha: convert to helper_cpu_halted_set
>   microblaze: convert to helper_cpu_halted_set
>   cpu: define cpu_halted helpers
>   tcg-runtime: convert to cpu_halted_set
>   arm: convert to cpu_halted
>   ppc: convert to cpu_halted
>   sh4: convert to cpu_halted
>   i386: convert to cpu_halted
>   lm32: convert to cpu_halted
>   m68k: convert to cpu_halted
>   mips: convert to cpu_halted
>   riscv: convert to cpu_halted
>   s390x: convert to cpu_halted
>   sparc: convert to cpu_halted
>   xtensa: convert to cpu_halted
>   gdbstub: convert to cpu_halted
>   openrisc: convert to cpu_halted
>   cpu-exec: convert to cpu_halted
>   cpu: convert to cpu_halted
>   cpu: define cpu_interrupt_request helpers
>   exec: use cpu_reset_interrupt
>   arm: convert to cpu_interrupt_request
>   i386: convert to cpu_interrupt_request
>   i386/kvm: convert to cpu_interrupt_request
>   i386/hax-all: convert to cpu_interrupt_request
>   i386/whpx-all: convert to cpu_interrupt_request
>   i386/hvf: convert to cpu_request_interrupt
>   ppc: convert to cpu_interrupt_request
>   sh4: convert to cpu_interrupt_request
>   cris: convert to cpu_interrupt_request
>   hppa: convert to cpu_interrupt_request
>   lm32: convert to cpu_interrupt_request
>   m68k: convert to cpu_interrupt_request
>   mips: convert to cpu_interrupt_request
>   nios: convert to cpu_interrupt_request
>   s390x: convert to cpu_interrupt_request
>   alpha: convert to cpu_interrupt_request
>   moxie: convert to cpu_interrupt_request
>   sparc: convert to cpu_interrupt_request
>   openrisc: convert to cpu_interrupt_request
>   unicore32: convert to cpu_interrupt_request
>   microblaze: convert to cpu_interrupt_request
>   accel/tcg: convert to cpu_interrupt_request
>   cpu: convert to interrupt_request
>   cpu: call .cpu_has_work with the CPU lock held
>   cpu: introduce cpu_has_work_with_iothread_lock
>   ppc: convert to cpu_has_work_with_iothread_lock
>   mips: convert to cpu_has_work_with_iothread_lock
>   s390x: convert to cpu_has_work_with_iothread_lock
>   riscv: convert to cpu_has_work_with_iothread_lock
>   sparc: convert to cpu_has_work_with_iothread_lock
>   xtensa: convert to cpu_has_work_with_iothread_lock
>   cpu: rename all_cpu_threads_idle to qemu_tcg_rr_all_cpu_threads_idle
>   cpu: protect CPU state with cpu->lock instead of the BQL
>   cpus-common: release BQL earlier in run_on_cpu
>   cpu: add async_run_on_cpu_no_bql
>   cputlb: queue async flush jobs without the BQL
>
> Paolo Bonzini (4):
>   ppc: use cpu_reset_interrupt
>   i386: use cpu_reset_interrupt
>   s390x: use cpu_reset_interrupt
>   openrisc: use cpu_reset_interrupt
>
> Robert Foley (1):
>   hw/semihosting: convert to cpu_halted_set
>
>  accel/tcg/cpu-exec.c            |  40 ++-
>  accel/tcg/cputlb.c              |  10 +-
>  accel/tcg/tcg-all.c             |  12 +-
>  accel/tcg/tcg-runtime.c         |   7 +
>  accel/tcg/tcg-runtime.h         |   2 +
>  accel/tcg/translate-all.c       |   2 +-
>  cpus-common.c                   | 129 +++++++---
>  cpus.c                          | 438 ++++++++++++++++++++++++++------
>  exec.c                          |   2 +-
>  gdbstub.c                       |   4 +-
>  hw/arm/omap1.c                  |   4 +-
>  hw/arm/pxa2xx_gpio.c            |   2 +-
>  hw/arm/pxa2xx_pic.c             |   2 +-
>  hw/core/cpu.c                   |  29 +--
>  hw/core/machine-qmp-cmds.c      |   2 +-
>  hw/intc/s390_flic.c             |   4 +-
>  hw/mips/cps.c                   |   2 +-
>  hw/misc/mips_itu.c              |   4 +-
>  hw/openrisc/cputimer.c          |   2 +-
>  hw/ppc/e500.c                   |   4 +-
>  hw/ppc/ppc.c                    |  12 +-
>  hw/ppc/ppce500_spin.c           |   6 +-
>  hw/ppc/spapr_cpu_core.c         |   4 +-
>  hw/ppc/spapr_hcall.c            |  14 +-
>  hw/ppc/spapr_rtas.c             |   8 +-
>  hw/semihosting/console.c        |   4 +-
>  hw/sparc/leon3.c                |   2 +-
>  hw/sparc/sun4m.c                |   8 +-
>  hw/sparc64/sparc64.c            |   8 +-
>  include/hw/core/cpu.h           | 197 ++++++++++++--
>  stubs/Makefile.objs             |   1 +
>  stubs/cpu-lock.c                |  35 +++
>  target/alpha/cpu.c              |   8 +-
>  target/alpha/translate.c        |   6 +-
>  target/arm/arm-powerctl.c       |   6 +-
>  target/arm/cpu.c                |   8 +-
>  target/arm/helper.c             |  16 +-
>  target/arm/machine.c            |   2 +-
>  target/arm/op_helper.c          |   2 +-
>  target/cris/cpu.c               |   2 +-
>  target/cris/helper.c            |   4 +-
>  target/cris/translate.c         |   5 +-
>  target/hppa/cpu.c               |   2 +-
>  target/hppa/translate.c         |   3 +-
>  target/i386/cpu.c               |   4 +-
>  target/i386/cpu.h               |   2 +-
>  target/i386/hax-all.c           |  42 +--
>  target/i386/helper.c            |   8 +-
>  target/i386/hvf/hvf.c           |  12 +-
>  target/i386/hvf/x86hvf.c        |  37 +--
>  target/i386/kvm.c               |  82 +++---
>  target/i386/misc_helper.c       |   2 +-
>  target/i386/seg_helper.c        |  13 +-
>  target/i386/svm_helper.c        |   6 +-
>  target/i386/whpx-all.c          |  57 +++--
>  target/lm32/cpu.c               |   2 +-
>  target/lm32/op_helper.c         |   4 +-
>  target/m68k/cpu.c               |   2 +-
>  target/m68k/op_helper.c         |   2 +-
>  target/m68k/translate.c         |   9 +-
>  target/microblaze/cpu.c         |   2 +-
>  target/microblaze/translate.c   |   4 +-
>  target/mips/cp0_helper.c        |   6 +-
>  target/mips/cpu.c               |  11 +-
>  target/mips/kvm.c               |   4 +-
>  target/mips/op_helper.c         |   2 +-
>  target/mips/translate.c         |   4 +-
>  target/moxie/cpu.c              |   2 +-
>  target/nios2/cpu.c              |   2 +-
>  target/openrisc/cpu.c           |   4 +-
>  target/openrisc/sys_helper.c    |   4 +-
>  target/ppc/excp_helper.c        |   6 +-
>  target/ppc/helper_regs.h        |   2 +-
>  target/ppc/kvm.c                |   6 +-
>  target/ppc/translate.c          |   6 +-
>  target/ppc/translate_init.inc.c |  41 +--
>  target/riscv/cpu.c              |   5 +-
>  target/riscv/op_helper.c        |   2 +-
>  target/s390x/cpu.c              |  28 +-
>  target/s390x/excp_helper.c      |   4 +-
>  target/s390x/kvm.c              |   2 +-
>  target/s390x/sigp.c             |   8 +-
>  target/sh4/cpu.c                |   2 +-
>  target/sh4/helper.c             |   2 +-
>  target/sh4/op_helper.c          |   2 +-
>  target/sparc/cpu.c              |   6 +-
>  target/sparc/helper.c           |   2 +-
>  target/unicore32/cpu.c          |   2 +-
>  target/unicore32/softmmu.c      |   2 +-
>  target/xtensa/cpu.c             |   6 +-
>  target/xtensa/exc_helper.c      |   2 +-
>  target/xtensa/helper.c          |   2 +-
>  92 files changed, 1067 insertions(+), 464 deletions(-)
>  create mode 100644 stubs/cpu-lock.c
>
> --
> 2.17.1
>
>

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