10:45 p.m.
From: Zhao Liu <zhao1.liu(a)intel.com>
The "parameter=0" SMP configurations have been marked as deprecated
since v6.2.
For these cases, -smp currently returns the warning and adjusts the
zeroed parameters to 1 by default.
Remove the above compatibility logic in v9.0, and return error directly
if any -smp parameter is set as 0.
Signed-off-by: Zhao Liu <zhao1.liu(a)intel.com>
---
docs/about/deprecated.rst | 16 ----------------
docs/about/removed-features.rst | 15 +++++++++++++++
hw/core/machine-smp.c | 5 +++--
3 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 36bd3e15ef06..872974640252 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -36,22 +36,6 @@ and will cause a warning.
The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on``
rather than ``delay=off``.
-``-smp`` ("parameter=0" SMP configurations) (since 6.2)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''
-
-Specified CPU topology parameters must be greater than zero.
-
-In the SMP configuration, users should either provide a CPU topology
-parameter with a reasonable value (greater than zero) or just omit it
-and QEMU will compute the missing value.
-
-However, historically it was implicitly allowed for users to provide
-a parameter with zero value, which is meaningless and could also possibly
-cause unexpected results in the -smp parsing. So support for this kind of
-configurations (e.g. -smp 8,sockets=0) is deprecated since 6.2 and will
-be removed in the near future, users have to ensure that all the topology
-members described with -smp are greater than zero.
-
Plugin argument passing through ``arg=<string>`` (since 6.1)
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index 417a0e4fa1d9..f9cf874f7b1f 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -489,6 +489,21 @@ The ``-singlestep`` option has been turned into an accelerator
property,
and given a name that better reflects what it actually does.
Use ``-accel tcg,one-insn-per-tb=on`` instead.
+``-smp`` ("parameter=0" SMP configurations) (removed in 9.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Specified CPU topology parameters must be greater than zero.
+
+In the SMP configuration, users should either provide a CPU topology
+parameter with a reasonable value (greater than zero) or just omit it
+and QEMU will compute the missing value.
+
+However, historically it was implicitly allowed for users to provide
+a parameter with zero value, which is meaningless and could also possibly
+cause unexpected results in the -smp parsing. So support for this kind of
+configurations (e.g. -smp 8,sockets=0) is removed since 9.0, users have
+to ensure that all the topology members described with -smp are greater
+than zero.
User-mode emulator command line arguments
-----------------------------------------
diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c
index 25019c91ee36..96533886b14e 100644
--- a/hw/core/machine-smp.c
+++ b/hw/core/machine-smp.c
@@ -105,8 +105,9 @@ void machine_parse_smp_config(MachineState *ms,
(config->has_cores && config->cores == 0) ||
(config->has_threads && config->threads == 0) ||
(config->has_maxcpus && config->maxcpus == 0)) {
- warn_report("Deprecated CPU topology (considered invalid): "
- "CPU topology parameters must be greater than zero");
+ error_setg(errp, "Invalid CPU topology: "
+ "CPU topology parameters must be greater than zero");
+ return;
}
/*
--
2.34.1
11:50 p.m.
New subject: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0" SMP
configurations
On 04/03/2024 05.45, Zhao Liu wrote:
From: Zhao Liu <zhao1.liu(a)intel.com>
The "parameter=0" SMP configurations have been marked as deprecated
since v6.2.
For these cases, -smp currently returns the warning and adjusts the
zeroed parameters to 1 by default.
Remove the above compatibility logic in v9.0, and return error directly
if any -smp parameter is set as 0.
Signed-off-by: Zhao Liu <zhao1.liu(a)intel.com>
---
docs/about/deprecated.rst | 16 ----------------
docs/about/removed-features.rst | 15 +++++++++++++++
hw/core/machine-smp.c | 5 +++--
3 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 36bd3e15ef06..872974640252 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -36,22 +36,6 @@ and will cause a warning.
The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on``
rather than ``delay=off``.
-``-smp`` ("parameter=0" SMP configurations) (since 6.2)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''
-
-Specified CPU topology parameters must be greater than zero.
-
-In the SMP configuration, users should either provide a CPU topology
-parameter with a reasonable value (greater than zero) or just omit it
-and QEMU will compute the missing value.
-
-However, historically it was implicitly allowed for users to provide
-a parameter with zero value, which is meaningless and could also possibly
-cause unexpected results in the -smp parsing. So support for this kind of
-configurations (e.g. -smp 8,sockets=0) is deprecated since 6.2 and will
-be removed in the near future, users have to ensure that all the topology
-members described with -smp are greater than zero.
-
Plugin argument passing through ``arg=<string>`` (since 6.1)
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index 417a0e4fa1d9..f9cf874f7b1f 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -489,6 +489,21 @@ The ``-singlestep`` option has been turned into an accelerator
property,
and given a name that better reflects what it actually does.
Use ``-accel tcg,one-insn-per-tb=on`` instead.
+``-smp`` ("parameter=0" SMP configurations) (removed in 9.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Specified CPU topology parameters must be greater than zero.
+
+In the SMP configuration, users should either provide a CPU topology
+parameter with a reasonable value (greater than zero) or just omit it
+and QEMU will compute the missing value.
+
+However, historically it was implicitly allowed for users to provide
+a parameter with zero value, which is meaningless and could also possibly
+cause unexpected results in the -smp parsing. So support for this kind of
+configurations (e.g. -smp 8,sockets=0) is removed since 9.0, users have
+to ensure that all the topology members described with -smp are greater
+than zero.
User-mode emulator command line arguments
-----------------------------------------
diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c
index 25019c91ee36..96533886b14e 100644
--- a/hw/core/machine-smp.c
+++ b/hw/core/machine-smp.c
@@ -105,8 +105,9 @@ void machine_parse_smp_config(MachineState *ms,
(config->has_cores && config->cores == 0) ||
(config->has_threads && config->threads == 0) ||
(config->has_maxcpus && config->maxcpus == 0)) {
- warn_report("Deprecated CPU topology (considered invalid): "
- "CPU topology parameters must be greater than zero");
+ error_setg(errp, "Invalid CPU topology: "
+ "CPU topology parameters must be greater than zero");
+ return;
}
Reviewed-by: Thomas Huth <thuth(a)redhat.com>
11:53 p.m.
On Mon, 4 Mar 2024 at 10:02, Zhao Liu <zhao1.liu(a)linux.intel.com> wrote:
diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c
index 25019c91ee36..96533886b14e 100644
--- a/hw/core/machine-smp.c
+++ b/hw/core/machine-smp.c
@@ -105,8 +105,9 @@ void machine_parse_smp_config(MachineState *ms,
(config->has_cores && config->cores == 0) ||
(config->has_threads && config->threads == 0) ||
(config->has_maxcpus && config->maxcpus == 0)) {
- warn_report("Deprecated CPU topology (considered invalid): "
- "CPU topology parameters must be greater than zero");
+ error_setg(errp, "Invalid CPU topology: "
+ "CPU topology parameters must be greater than zero");
+ return;
}
unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
...
if (config->has_maxcpus && config->maxcpus == 0)
* The check (has_maxcpus && maxcpus == 0) seems to be repeating above,
maybe we could check if (maxcpus == 0) error_setg(). And same for
other topology parameters?
* Also a check to ensure cpus <= maxcpus is required I think.
Thank you.
---
- Prasad
1:03 a.m.
New subject: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0" SMP
configurations
Hi Prasad,
On Mon, Mar 04, 2024 at 11:23:58AM +0530, Prasad Pandit wrote:
Date: Mon, 4 Mar 2024 11:23:58 +0530
From: Prasad Pandit <ppandit(a)redhat.com>
Subject: Re: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0"
SMP configurations
On Mon, 4 Mar 2024 at 10:02, Zhao Liu <zhao1.liu(a)linux.intel.com> wrote:
> diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c
> index 25019c91ee36..96533886b14e 100644
> --- a/hw/core/machine-smp.c
> +++ b/hw/core/machine-smp.c
> @@ -105,8 +105,9 @@ void machine_parse_smp_config(MachineState *ms,
> (config->has_cores && config->cores == 0) ||
> (config->has_threads && config->threads == 0) ||
> (config->has_maxcpus && config->maxcpus == 0)) {
> - warn_report("Deprecated CPU topology (considered invalid): "
> - "CPU topology parameters must be greater than
zero");
> + error_setg(errp, "Invalid CPU topology: "
> + "CPU topology parameters must be greater than zero");
> + return;
> }
unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
This indicates the default maxcpus is initialized as 0 if user doesn't
specifies it.
For this case - no user configuration - maxcpus will be re-calculated
as:
maxcpus = maxcpus > 0 ? maxcpus : drawers * books * sockets * dies *
clusters * cores * threads; (*)
...
if (config->has_maxcpus && config->maxcpus == 0)
This check only wants to identify the case that user sets the 0.
* The check (has_maxcpus && maxcpus == 0) seems to be repeating above,
maybe we could check if (maxcpus == 0) error_setg().
If the default maxcpus is initialized as 0, then (maxcpus == 0) will
fail if user doesn't set maxcpus.
However, we could initialize maxcpus as other default value, e.g.,
maxcpus = config->has_maxcpus ? config->maxcpus : 1.
But it is still necessary to distinguish whether maxcpus is user-set or
auto-initialized.
If it is user-set, -smp should fail is there's invalid maxcpus/invalid
topology.
Otherwise, if it is auto-initialized, its value should be adjusted based
on other topology components as the above calculation in (*).
And same for
other topology parameters?
Other parameters also have the similar needs to distinguish if they're
set by user. So the check needs to also cover has_* fields.
* Also a check to ensure cpus <= maxcpus is required I think.
Yes, the valid topology needs this. This code block already covers this
case ;-):
if (maxcpus < cpus) {
g_autofree char *topo_msg = cpu_hierarchy_to_string(ms);
error_setg(errp, "Invalid CPU topology: "
"maxcpus must be equal to or greater than smp: "
"%s == maxcpus (%u) < smp_cpus (%u)",
topo_msg, maxcpus, cpus);
return;
}
Thanks,
Zhao
2:21 a.m.
Hello Zhao,
On Mon, 4 Mar 2024 at 12:19, Zhao Liu <zhao1.liu(a)linux.intel.com> wrote:
> unsigned maxcpus = config->has_maxcpus ? config->maxcpus :
0;
This indicates the default maxcpus is initialized as 0 if user doesn't
specifies it.
* 'has_maxcpus' should be set only if maxcpus > 0. If maxcpus == 0,
then setting 'has_maxcpus=1' seems convoluted.
However, we could initialize maxcpus as other default value, e.g.,
maxcpus = config->has_maxcpus ? config->maxcpus : 1.
===
hw/core/machine.c
machine_initfn
/* default to mc->default_cpus */
ms->smp.cpus = mc->default_cpus;
ms->smp.max_cpus = mc->default_cpus;
static void machine_class_base_init(ObjectClass *oc, void *data)
{
MachineClass *mc = MACHINE_CLASS(oc);
mc->max_cpus = mc->max_cpus ?: 1;
mc->min_cpus = mc->min_cpus ?: 1;
mc->default_cpus = mc->default_cpus ?: 1;
}
===
* Looking at the above bits, it seems smp.cpus & smp.max_cpus are
initialised to 1 via default_cpus in MachineClass object.
> if (config->has_maxcpus && config->maxcpus == 0)
This check only wants to identify the case that user sets the 0.
If the default maxcpus is initialized as 0, then (maxcpus == 0) will
fail if user doesn't set maxcpus.
But it is still necessary to distinguish whether maxcpus is user-set or
auto-initialized.
* If it is set to zero(0) either by user or by auto-initialise, it is
still invalid, right?
If it is user-set, -smp should fail is there's invalid
maxcpus/invalid
topology.
Otherwise, if it is auto-initialized, its value should be adjusted based
on other topology components as the above calculation in (*).
* Why have such diverging ways?
* Could we simplify it as
- If cpus/maxcpus==0, it is invalid, show an error and exit.
- If cpus/maxcpus > 0, but incorrect for topology, then
re-calculate the correct value based on topology parameters. If the
re-calculated value is still incorrect or unsatisfactory, then show an
error and exit.
* Saying that user setting cpu/maxcpus=0 is invalid and
auto-initialising it to zero(0) is valid, is not consistent.
...wdyt?
---
- Prasad
1:42 a.m.
New subject: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0" SMP
configurations
Hi Prasad,
On Mon, 4 Mar 2024 at 12:19, Zhao Liu
<zhao1.liu(a)linux.intel.com> wrote:
> > unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
>
> This indicates the default maxcpus is initialized as 0 if user doesn't
> specifies it.
* 'has_maxcpus' should be set only if maxcpus > 0. If maxcpus == 0,
then setting 'has_maxcpus=1' seems convoluted.
After simple test, if user sets maxcpus as 0, the has_maxcpus will be
true as well...I think it's related with QAPI code generation logic.
> However, we could initialize maxcpus as other default value,
e.g.,
>
> maxcpus = config->has_maxcpus ? config->maxcpus : 1.
===
hw/core/machine.c
machine_initfn
/* default to mc->default_cpus */
ms->smp.cpus = mc->default_cpus;
ms->smp.max_cpus = mc->default_cpus;
static void machine_class_base_init(ObjectClass *oc, void *data)
{
MachineClass *mc = MACHINE_CLASS(oc);
mc->max_cpus = mc->max_cpus ?: 1;
mc->min_cpus = mc->min_cpus ?: 1;
mc->default_cpus = mc->default_cpus ?: 1;
}
===
* Looking at the above bits, it seems smp.cpus & smp.max_cpus are
initialised to 1 via default_cpus in MachineClass object.
Yes.
The maxcpus I mentioned is a local virable in
machine_parse_smp_config(), whihc is used to do sanity-check check.
In machine_parse_smp_config(), when we can confirm the topology is
valid, then ms->smp.cpus and ms->smp.max_cpus are set with the valid
virables (cpus and maxcpus).
>> if (config->has_maxcpus && config->maxcpus ==
0)
> This check only wants to identify the case that user sets the 0.
> If the default maxcpus is initialized as 0, then (maxcpus == 0) will
> fail if user doesn't set maxcpus.
>
> But it is still necessary to distinguish whether maxcpus is user-set or
> auto-initialized.
* If it is set to zero(0) either by user or by auto-initialise, it is
still invalid, right?
The latter, "auto-initialise", means user could omit "cpus" and
"maxcpus"
parameters in -smp.
Even though the local variable "cpus" and "maxcpus" are initialized
as
0, eventually ms->smp.cpus and ms->smp.max_cpus will still have the
valid values.
> If it is user-set, -smp should fail is there's invalid
maxcpus/invalid
> topology.
>
> Otherwise, if it is auto-initialized, its value should be adjusted based
> on other topology components as the above calculation in (*).
* Why have such diverging ways?
* Could we simplify it as
- If cpus/maxcpus==0, it is invalid, show an error and exit.
Hmm, the origial behavior means if user doesn't set cpus=*/maxcpus=* in
-smp, then QEMU will auto-complete these 2 fields.
If we also return error for the above case that user omits cpus and
maxcpus parameters, then this change the QEMU's API and we need to mark
feature that the cpus/maxcpus parameter can be omitted as deprecated and
remove it out. Just like what I did in this patch for zeroed-parameter
case.
I feel if there's no issue then it's not necessary to change the API. Do
you agree?
- If cpus/maxcpus > 0, but incorrect for topology, then
re-calculate the correct value based on topology parameters. If the
re-calculated value is still incorrect or unsatisfactory, then show an
error and exit.
Yes, this case is right.
* Saying that user setting cpu/maxcpus=0 is invalid and
auto-initialising it to zero(0) is valid, is not consistent.
I think "auto-initialising it to zero(0)" doesn't means we re-initialize
ms->smp.cpus and ms->smp.max_cpus as 0 (these 2 fields store actual basic
topology information and they're defult as 1 as you said above).
Does my explaination address your concern? ;-)
Thanks,
Zhao
6:37 a.m.
Hi,
On Tue, 5 Mar 2024 at 12:59, Zhao Liu <zhao1.liu(a)linux.intel.com> wrote:
After simple test, if user sets maxcpus as 0, the has_maxcpus will
be
true as well...I think it's related with QAPI code generation logic.
* Right.
[Maybe we digressed a bit in the discussion, so I snipped much of the
details here. Sorry about that.]
* "if user sets maxcpus as 0, the has_maxcpus will be true as well",
ie if 'has_*' fields are always set
unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
then checking 'config->has_maxcpus ?' above is probably not required I
think. It could just be
maxcpus = config->maxcpus
If a user does not specify config->maxcpus with -smp option, then it
could default to zero(0) in 'config' parameter? (same for other config
fields)
* If such change requires API changes (I'm not sure how), then
probably it is outside the scope of this patch.
...wdyt?
Thank you.
---
- Prasad
9:33 p.m.
New subject: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0" SMP
configurations
Hi Prasad,
On Tue, 5 Mar 2024 at 12:59, Zhao Liu
<zhao1.liu(a)linux.intel.com> wrote:
> After simple test, if user sets maxcpus as 0, the has_maxcpus will be
> true as well...I think it's related with QAPI code generation logic.
* Right.
[Maybe we digressed a bit in the discussion, so I snipped much of the
details here. Sorry about that.]
* "if user sets maxcpus as 0, the has_maxcpus will be true as well",
ie if 'has_*' fields are always set
unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
then checking 'config->has_maxcpus ?' above is probably not required I
think. It could just be
maxcpus = config->maxcpus
Yes.
If a user does not specify config->maxcpus with -smp option, then
it
could default to zero(0) in 'config' parameter? (same for other config
fields)
Yes. I could post another series for this cleanup soon.
* If such change requires API changes (I'm not sure how), then
probably it is outside the scope of this patch.
...wdyt?
The above change you suggested doesn't require API changes ;-).
Thanks,
Zhao
10:49 p.m.
Hello Zhao,
On Wed, 6 Mar 2024 at 08:49, Zhao Liu <zhao1.liu(a)linux.intel.com> wrote:
> then checking 'config->has_maxcpus ?' above is
probably not required I
> think. It could just be
>
> maxcpus = config->maxcpus
Yes.
> If a user does not specify config->maxcpus with -smp option, then it
> could default to zero(0) in 'config' parameter? (same for other config
> fields)
Yes. I could post another series for this cleanup soon.
The above change you suggested doesn't require API changes ;-).
* Great! (Communication is the most difficult skill to master. :))
* If you plan to send a separate patch for above refactoring, then I'd
add Reviewed-by for this one.
Reviewed-by: Prasad Pandit <pjp(a)fedoraproject.org>
Thank you.
---
- Prasad
12:27 a.m.
New subject: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0" SMP
configurations
On Wed, Mar 06, 2024 at 10:19:41AM +0530, Prasad Pandit wrote:
Date: Wed, 6 Mar 2024 10:19:41 +0530
From: Prasad Pandit <ppandit(a)redhat.com>
Subject: Re: [PATCH] hw/core/machine-smp: Remove deprecated "parameter=0"
SMP configurations
Hello Zhao,
On Wed, 6 Mar 2024 at 08:49, Zhao Liu <zhao1.liu(a)linux.intel.com> wrote:
>> then checking 'config->has_maxcpus ?' above is probably not required
I
>> think. It could just be
>>
>> maxcpus = config->maxcpus
>
> Yes.
>
> > If a user does not specify config->maxcpus with -smp option, then it
> > could default to zero(0) in 'config' parameter? (same for other config
> > fields)
>
> Yes. I could post another series for this cleanup soon.
> The above change you suggested doesn't require API changes ;-).
* Great! (Communication is the most difficult skill to master. :))
* If you plan to send a separate patch for above refactoring, then I'd
add Reviewed-by for this one.
Yeah, I will send a series, which will also include this patch, to avoid
trivial smp cleanup fragmentation.
Reviewed-by: Prasad Pandit <pjp(a)fedoraproject.org>
Thanks!
-Zhao
261
days inactive
263
days old
9 comments
3 participants
participants (3)
-
Prasad Pandit -
Thomas Huth -
Zhao Liu