Le 21/11/2020 à 22:35, Peter Maydell a écrit : > The documentation for the icount documentation has some minor issues: > * in a couple of places it says "sleep=on|off" when in the context of the > sentence it means specifically "sleep=on" > * the synopsis line for the documentation has drifted out of sync > with the synopsis line in the DEF() macro (used for "-help" output) > * the synopsis line in the DEF() macro is missing a "][" between > the sleep= part and the rr= part > * the synopsis line doesn't indicate that rrsnapshot is an optional > part of the rr=mode,rrfile=filename subgrouping > * we don't document that sleep=on can't be used with shift=auto > or align=on > * the rr option description had some minor grammar and formatting > errors and was a bit terse > * in commit f1f4b57e88ff in 2015 the documentation of the sleep= > suboption got added between the two paragraphs defining general > behaviour of the icount option. This meant that the second > paragraph talking about the behaviour of "this option" reads as > if it's talking about sleep=on, when it's really describing -icount > as a whole. The paragraph is better moved back up to above the > sleep= section. > * the summary text displayed in "-help" output didn't mention > the record-and-replay part > > Fix these errors. > > Fixes: https://bugs.launchpad.net/qemu/+bug/1774412 > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> > --- > qemu-options.hx | 42 ++++++++++++++++++++++++------------------ > 1 file changed, 24 insertions(+), 18 deletions(-) > > diff --git a/qemu-options.hx b/qemu-options.hx > index 2c83390504d..41cb42e7a5d 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -3956,30 +3956,34 @@ SRST > ERST > > DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ > - "-icount > [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" > \ > + "-icount > [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" > \ > " enable virtual instruction counter with 2^N clock ticks > per\n" \ > " instruction, enable aligning the host and virtual > clocks\n" \ > - " or disable real time cpu sleeping\n", QEMU_ARCH_ALL) > + " or disable real time cpu sleeping, and optionally > enable\n" \ > + " record-and-replay mode\n", QEMU_ARCH_ALL) > SRST > -``-icount > [shift=N|auto][,rr=record|replay,rrfile=filename,rrsnapshot=snapshot]`` > +``-icount > [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` > Enable virtual instruction counter. The virtual cpu will execute one > instruction every 2^N ns of virtual time. If ``auto`` is specified > then the virtual cpu speed will be automatically adjusted to keep > virtual time within a few seconds of real time. > > - When the virtual cpu is sleeping, the virtual time will advance at > - default speed unless ``sleep=on|off`` is specified. With > - ``sleep=on|off``, the virtual time will jump to the next timer > - deadline instantly whenever the virtual cpu goes to sleep mode and > - will not advance if no timer is enabled. This behavior give > - deterministic execution times from the guest point of view. > - > Note that while this option can give deterministic behavior, it does > not provide cycle accurate emulation. Modern CPUs contain > superscalar out of order cores with complex cache hierarchies. The > number of instructions executed often has little or no correlation > with actual performance. > > + When the virtual cpu is sleeping, the virtual time will advance at > + default speed unless ``sleep=on`` is specified. With > + ``sleep=on``, the virtual time will jump to the next timer > + deadline instantly whenever the virtual cpu goes to sleep mode and > + will not advance if no timer is enabled. This behavior gives > + deterministic execution times from the guest point of view. > + The default if icount is enabled is ``sleep=off``. > + ``sleep=on`` cannot be used together with either ``shift=auto`` > + or ``align=on``. > + > ``align=on`` will activate the delay algorithm which will try to > synchronise the host clock and the virtual clock. The goal is to > have a guest running at the real frequency imposed by the shift > @@ -3989,15 +3993,17 @@ SRST > ``shift`` is ``auto``. Note: The sync algorithm will work for those > shift values for which the guest clock runs ahead of the host clock. > Typically this happens when the shift value is high (how high > - depends on the host machine). > + depends on the host machine). The default if icount is enabled > + is ``align=off``. > > - When ``rr`` option is specified deterministic record/replay is > - enabled. Replay log is written into filename file in record mode and > - read from this file in replay mode. > - > - Option rrsnapshot is used to create new vm snapshot named snapshot > - at the start of execution recording. In replay mode this option is > - used to load the initial VM state. > + When the ``rr`` option is specified deterministic record/replay is > + enabled. The ``rrfile=`` option must also be provided to > + specify the path to the replay log. In record mode data is written > + to this file, and in replay mode it is read back. > + If the ``rrsnapshot`` option is given then it specifies a VM snapshot > + name. In record mode, a new VM snapshot with the given name is created > + at the start of execution recording. In replay mode this option > + specifies the snapshot name used to load the initial VM state. > ERST > > DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ >
Applied to my linux-user-for-6.0 branch. Thanks, Laurent
