[PATCH] buitin-kvm: Update cmd_kvm() to check perf_host value

[PATCH] buitin-kvm: Update cmd_kvm() to check perf_host value

[yskelg]

From: Yunseong Kim <yskelg@gmail.com>

According to perf-kvm.txt, the default operation is --guest, meaning
perf_host should be set to false and perf_guest to true. Currently,
the incorrect usage of --no-host and --no-guest still results in
the default --guest operation.

This patch updates the usage messages to include the --no-guest option
for those who only want host data, as well as the --no-host and
--no-guest case.

Signed-off-by: Yunseong Kim <yskelg@gmail.com>
---
 tools/perf/builtin-kvm.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 71165036e4ca..654a07658cdd 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -2129,7 +2129,7 @@ int cmd_kvm(int argc, const char **argv)
 		OPT_BOOLEAN(0, "guest", &perf_guest,
 			    "Collect guest os data"),
 		OPT_BOOLEAN(0, "host", &perf_host,
-			    "Collect host os data"),
+			   "Collect host os data. Host only with --host --no-guest"),
 		OPT_STRING(0, "guestmount", &symbol_conf.guestmount, "directory",
 			   "guest mount directory under which every guest os"
 			   " instance has a subdir"),
@@ -2150,16 +2150,23 @@ int cmd_kvm(int argc, const char **argv)
 						"buildid-list", "stat", NULL };
 	const char *kvm_usage[] = { NULL, NULL };
 
-	perf_host  = 0;
-	perf_guest = 1;
+	/*
+	 * tools/perf/Documentation/perf-kvm.txt
+	 *
+	 *    Default('')         ->  perf.data.guest
+	 *    --host              ->  perf.data.kvm
+	 *    --guest             ->  perf.data.guest
+	 *    --host --guest      ->  perf.data.kvm
+	 *    --host --no-guest   ->  perf.data.host
+	 */
+	perf_host = false;
+	perf_guest = true;
 
 	argc = parse_options_subcommand(argc, argv, kvm_options, kvm_subcommands, kvm_usage,
 					PARSE_OPT_STOP_AT_NON_OPTION);
-	if (!argc)
+	if (!argc || (!perf_host && !perf_guest))
 		usage_with_options(kvm_usage, kvm_options);
 
-	if (!perf_host)
-		perf_guest = 1;
 
 	if (!file_name) {
 		file_name = get_filename_for_perf_kvm();
-- 
2.34.1

Re: [PATCH] buitin-kvm: Update cmd_kvm() to check perf_host value

[Namhyung Kim]

Hello,

On Wed, May 15, 2024 at 12:54 PM <yskelg@gmail.com> wrote:
>
> From: Yunseong Kim <yskelg@gmail.com>
>
> According to perf-kvm.txt, the default operation is --guest, meaning
> perf_host should be set to false and perf_guest to true. Currently,
> the incorrect usage of --no-host and --no-guest still results in
> the default --guest operation.

Hmm, right.. This is not good.

>
> This patch updates the usage messages to include the --no-guest option
> for those who only want host data, as well as the --no-host and
> --no-guest case.

I'm not sure if it's worth mentioning the host-only use case which is
not expected for this command.  I think it's enough to warn the
no-host and no-guest use cases.

>
> Signed-off-by: Yunseong Kim <yskelg@gmail.com>
> ---
>  tools/perf/builtin-kvm.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
> index 71165036e4ca..654a07658cdd 100644
> --- a/tools/perf/builtin-kvm.c
> +++ b/tools/perf/builtin-kvm.c
> @@ -2129,7 +2129,7 @@ int cmd_kvm(int argc, const char **argv)
>                 OPT_BOOLEAN(0, "guest", &perf_guest,
>                             "Collect guest os data"),
>                 OPT_BOOLEAN(0, "host", &perf_host,
> -                           "Collect host os data"),
> +                          "Collect host os data. Host only with --host --no-guest"),
>                 OPT_STRING(0, "guestmount", &symbol_conf.guestmount, "directory",
>                            "guest mount directory under which every guest os"
>                            " instance has a subdir"),
> @@ -2150,16 +2150,23 @@ int cmd_kvm(int argc, const char **argv)
>                                                 "buildid-list", "stat", NULL };
>         const char *kvm_usage[] = { NULL, NULL };
>
> -       perf_host  = 0;
> -       perf_guest = 1;
> +       /*
> +        * tools/perf/Documentation/perf-kvm.txt
> +        *
> +        *    Default('')         ->  perf.data.guest
> +        *    --host              ->  perf.data.kvm
> +        *    --guest             ->  perf.data.guest
> +        *    --host --guest      ->  perf.data.kvm
> +        *    --host --no-guest   ->  perf.data.host
> +        */
> +       perf_host = false;
> +       perf_guest = true;

Probably not needed.

>
>         argc = parse_options_subcommand(argc, argv, kvm_options, kvm_subcommands, kvm_usage,
>                                         PARSE_OPT_STOP_AT_NON_OPTION);
> -       if (!argc)
> +       if (!argc || (!perf_host && !perf_guest))
>                 usage_with_options(kvm_usage, kvm_options);
>
> -       if (!perf_host)
> -               perf_guest = 1;

Instead of showing the whole usage, I think it's better to
print a specific message for this case.

Oh, I've realized that we have 'h' modifier for hypervisors
(on ARM64?)  Then maybe no-host + no-guest is a valid
combination.  Probably we need to add --hypervisor option
then.

Thanks,
Namhyung


>
>         if (!file_name) {
>                 file_name = get_filename_for_perf_kvm();
> --
> 2.34.1
>

Re: [PATCH] buitin-kvm: Update cmd_kvm() to check perf_host value

[Yunseong Kim]

On 5/23/24 1:23 오후, Namhyung Kim wrote:
> Hello,
> 
> On Wed, May 15, 2024 at 12:54 PM <yskelg@gmail.com> wrote:
>>
>> From: Yunseong Kim <yskelg@gmail.com>
>>
>> According to perf-kvm.txt, the default operation is --guest, meaning
>> perf_host should be set to false and perf_guest to true. Currently,
>> the incorrect usage of --no-host and --no-guest still results in
>> the default --guest operation.
> 
> Hmm, right.. This is not good.
> 
>>
>> This patch updates the usage messages to include the --no-guest option
>> for those who only want host data, as well as the --no-host and
>> --no-guest case.
> 
> I'm not sure if it's worth mentioning the host-only use case which is
> not expected for this command.  I think it's enough to warn the
> no-host and no-guest use cases.

Thank you Namhyung for the code review!

I wasn't sure if it was necessary to mention that either.

I should have asked in the patch mail first.

>> Signed-off-by: Yunseong Kim <yskelg@gmail.com>
>> ---
>>  tools/perf/builtin-kvm.c | 19 +++++++++++++------
>>  1 file changed, 13 insertions(+), 6 deletions(-)
>>
>> diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
>> index 71165036e4ca..654a07658cdd 100644
>> --- a/tools/perf/builtin-kvm.c
>> +++ b/tools/perf/builtin-kvm.c
>> @@ -2129,7 +2129,7 @@ int cmd_kvm(int argc, const char **argv)
>>                 OPT_BOOLEAN(0, "guest", &perf_guest,
>>                             "Collect guest os data"),
>>                 OPT_BOOLEAN(0, "host", &perf_host,
>> -                           "Collect host os data"),
>> +                          "Collect host os data. Host only with --host --no-guest"),
>>                 OPT_STRING(0, "guestmount", &symbol_conf.guestmount, "directory",
>>                            "guest mount directory under which every guest os"
>>                            " instance has a subdir"),
>> @@ -2150,16 +2150,23 @@ int cmd_kvm(int argc, const char **argv)
>>                                                 "buildid-list", "stat", NULL };
>>         const char *kvm_usage[] = { NULL, NULL };
>>
>> -       perf_host  = 0;
>> -       perf_guest = 1;
>> +       /*
>> +        * tools/perf/Documentation/perf-kvm.txt
>> +        *
>> +        *    Default('')         ->  perf.data.guest
>> +        *    --host              ->  perf.data.kvm
>> +        *    --guest             ->  perf.data.guest
>> +        *    --host --guest      ->  perf.data.kvm
>> +        *    --host --no-guest   ->  perf.data.host
>> +        */
>> +       perf_host = false;
>> +       perf_guest = true;
> 
> Probably not needed.

I agree.

>>
>>         argc = parse_options_subcommand(argc, argv, kvm_options, kvm_subcommands, kvm_usage,
>>                                         PARSE_OPT_STOP_AT_NON_OPTION);
>> -       if (!argc)
>> +       if (!argc || (!perf_host && !perf_guest))
>>                 usage_with_options(kvm_usage, kvm_options);
>>
>> -       if (!perf_host)
>> -               perf_guest = 1;
> 
> Instead of showing the whole usage, I think it's better to
> print a specific message for this case.
> 
> Oh, I've realized that we have 'h' modifier for hypervisors
> (on ARM64?)  Then maybe no-host + no-guest is a valid
> combination.  Probably we need to add --hypervisor option
> then.
> 
> Thanks,
> Namhyung

Yes, I have a native Arm64 devlopment environment.

So I'll implement and test it and send the patch.


Thank you so much for the detailed review!


Warm Regards,

Yunseong Kim

>>
>>         if (!file_name) {
>>                 file_name = get_filename_for_perf_kvm();
>> --
>> 2.34.1
>>