diff mbox series

[v3,04/10] linux-user: Add '-one-insn-per-tb' option equivalent to '-singlestep'

Message ID 20230417164041.684562-5-peter.maydell@linaro.org
State New
Headers show
Series Deprecate/rename singlestep command line option, monitor interfaces | expand

Commit Message

Peter Maydell April 17, 2023, 4:40 p.m. UTC 
The '-singlestep' option is confusing, because it doesn't actually
have anything to do with single-stepping the CPU. What it does do
is force TCG emulation to put one guest instruction in each TB,
which can be useful in some situations.

Create a new command line argument -one-insn-per-tb, so we can
document that -singlestep is just a deprecated synonym for it,
and eventually perhaps drop it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
---
 docs/user/main.rst | 7 ++++++-
 linux-user/main.c  | 9 ++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

Comments

Philippe Mathieu-Daudé April 20, 2023, 9:13 a.m. UTC | #1 
On 17/4/23 18:40, Peter Maydell wrote:
> The '-singlestep' option is confusing, because it doesn't actually
> have anything to do with single-stepping the CPU. What it does do
> is force TCG emulation to put one guest instruction in each TB,
> which can be useful in some situations.
> 
> Create a new command line argument -one-insn-per-tb, so we can
> document that -singlestep is just a deprecated synonym for it,
> and eventually perhaps drop it.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: Warner Losh <imp@bsdimp.com>
> ---
>   docs/user/main.rst | 7 ++++++-
>   linux-user/main.c  | 9 ++++++---
>   2 files changed, 12 insertions(+), 4 deletions(-)


> @@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = {
>        "logfile",     "write logs to 'logfile' (default stderr)"},
>       {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,
>        "pagesize",   "set the host page size to 'pagesize'"},
> -    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_singlestep,
> -     "",           "run in singlestep mode"},
> +    {"one-insn-per-tb",
> +                   "QEMU_ONE_INSN_PER_TB",  false, handle_arg_one_insn_per_tb,
> +     "",           "run with one guest instruction per emulated TB"},
> +    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_one_insn_per_tb,
> +     "",           "deprecated synonym for -one-insn-per-tb"},

Maybe worth mentioning QEMU_ONE_INSN_PER_TB too here:

   "deprecated synonyms for -one-insn-per-tb and QEMU_ONE_INSN_PER_TB"

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

>       {"strace",     "QEMU_STRACE",      false, handle_arg_strace,
>        "",           "log system calls"},
>       {"seed",       "QEMU_RAND_SEED",   true,  handle_arg_seed,
Peter Maydell April 20, 2023, 9:19 a.m. UTC | #2 
On Thu, 20 Apr 2023 at 10:13, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>
> On 17/4/23 18:40, Peter Maydell wrote:
> > The '-singlestep' option is confusing, because it doesn't actually
> > have anything to do with single-stepping the CPU. What it does do
> > is force TCG emulation to put one guest instruction in each TB,
> > which can be useful in some situations.
> >
> > Create a new command line argument -one-insn-per-tb, so we can
> > document that -singlestep is just a deprecated synonym for it,
> > and eventually perhaps drop it.
> >
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> > Reviewed-by: Warner Losh <imp@bsdimp.com>
> > ---
> >   docs/user/main.rst | 7 ++++++-
> >   linux-user/main.c  | 9 ++++++---
> >   2 files changed, 12 insertions(+), 4 deletions(-)
>
>
> > @@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = {
> >        "logfile",     "write logs to 'logfile' (default stderr)"},
> >       {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,
> >        "pagesize",   "set the host page size to 'pagesize'"},
> > -    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_singlestep,
> > -     "",           "run in singlestep mode"},
> > +    {"one-insn-per-tb",
> > +                   "QEMU_ONE_INSN_PER_TB",  false, handle_arg_one_insn_per_tb,
> > +     "",           "run with one guest instruction per emulated TB"},
> > +    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_one_insn_per_tb,
> > +     "",           "deprecated synonym for -one-insn-per-tb"},
>
> Maybe worth mentioning QEMU_ONE_INSN_PER_TB too here:
>
>    "deprecated synonyms for -one-insn-per-tb and QEMU_ONE_INSN_PER_TB"

There's not a lot of space in the -help output, and I think in
context it's clear enough without.

thanks
-- PMM
Philippe Mathieu-Daudé April 20, 2023, 10:05 a.m. UTC | #3 
On 20/4/23 11:19, Peter Maydell wrote:
> On Thu, 20 Apr 2023 at 10:13, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>>
>> On 17/4/23 18:40, Peter Maydell wrote:
>>> The '-singlestep' option is confusing, because it doesn't actually
>>> have anything to do with single-stepping the CPU. What it does do
>>> is force TCG emulation to put one guest instruction in each TB,
>>> which can be useful in some situations.
>>>
>>> Create a new command line argument -one-insn-per-tb, so we can
>>> document that -singlestep is just a deprecated synonym for it,
>>> and eventually perhaps drop it.
>>>
>>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>>> Reviewed-by: Warner Losh <imp@bsdimp.com>
>>> ---
>>>    docs/user/main.rst | 7 ++++++-
>>>    linux-user/main.c  | 9 ++++++---
>>>    2 files changed, 12 insertions(+), 4 deletions(-)
>>
>>
>>> @@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = {
>>>         "logfile",     "write logs to 'logfile' (default stderr)"},
>>>        {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,
>>>         "pagesize",   "set the host page size to 'pagesize'"},
>>> -    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_singlestep,
>>> -     "",           "run in singlestep mode"},
>>> +    {"one-insn-per-tb",
>>> +                   "QEMU_ONE_INSN_PER_TB",  false, handle_arg_one_insn_per_tb,
>>> +     "",           "run with one guest instruction per emulated TB"},
>>> +    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_one_insn_per_tb,
>>> +     "",           "deprecated synonym for -one-insn-per-tb"},
>>
>> Maybe worth mentioning QEMU_ONE_INSN_PER_TB too here:
>>
>>     "deprecated synonyms for -one-insn-per-tb and QEMU_ONE_INSN_PER_TB"
> 
> There's not a lot of space in the -help output, and I think in
> context it's clear enough without.

Fine.
diff mbox series

Patch

diff --git a/docs/user/main.rst b/docs/user/main.rst
index 6f2ffa080f7..f9ac701f4b1 100644
--- a/docs/user/main.rst
+++ b/docs/user/main.rst
@@ -93,8 +93,13 @@  Debug options:
 ``-g port``
    Wait gdb connection to port
 
+``-one-insn-per-tb``
+   Run the emulation with one guest instruction per translation block.
+   This slows down emulation a lot, but can be useful in some situations,
+   such as when trying to analyse the logs produced by the ``-d`` option.
+
 ``-singlestep``
-   Run the emulation in single step mode.
+   This is a deprecated synonym for the ``-one-insn-per-tb`` option.
 
 Environment variables:
 
diff --git a/linux-user/main.c b/linux-user/main.c
index c7020b413bc..5defe5a6db8 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -409,7 +409,7 @@  static void handle_arg_reserved_va(const char *arg)
     reserved_va = val ? val - 1 : 0;
 }
 
-static void handle_arg_singlestep(const char *arg)
+static void handle_arg_one_insn_per_tb(const char *arg)
 {
     opt_one_insn_per_tb = true;
 }
@@ -500,8 +500,11 @@  static const struct qemu_argument arg_table[] = {
      "logfile",     "write logs to 'logfile' (default stderr)"},
     {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,
      "pagesize",   "set the host page size to 'pagesize'"},
-    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_singlestep,
-     "",           "run in singlestep mode"},
+    {"one-insn-per-tb",
+                   "QEMU_ONE_INSN_PER_TB",  false, handle_arg_one_insn_per_tb,
+     "",           "run with one guest instruction per emulated TB"},
+    {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_one_insn_per_tb,
+     "",           "deprecated synonym for -one-insn-per-tb"},
     {"strace",     "QEMU_STRACE",      false, handle_arg_strace,
      "",           "log system calls"},
     {"seed",       "QEMU_RAND_SEED",   true,  handle_arg_seed,