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

PATCH In review [email protected] 2 participants 3 messages May 15, 2024 – May 27, 2024 perf events

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PATCH 1/1 buitin-kvm: Update cmd_kvm() to check perf_host value

From: Yunseong Kim <[email protected]>

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.

---
 tools/perf/builtin-kvm.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)
tools/perf/builtin-kvm.c +13 -6
index 71165036e4ca..654a07658cdd 100644
@@ -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();
Signature · 1 line
2.34.1
maintainer
#1 lore raw

Hello,

Quoted 7 lines · On Wed, May 15, 2024 at 12:54 PM <[email protected]> wrote:

From: Yunseong Kim <[email protected]>

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.

Quoted 4 lines

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.

Quoted 26 lines
---
 tools/perf/builtin-kvm.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)
tools/perf/builtin-kvm.c +2 -3
index 71165036e4ca..654a07658cdd 100644
@@ -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/builtin-kvm.c int cmd_kvm(int argc, const char **argv) · line 2163

Quoted 10 lines
tools/perf/builtin-kvm.c +10 -0
+        * 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.

tools/perf/builtin-kvm.c int cmd_kvm(int argc, const char **argv) · line 2162

Quoted 9 lines
tools/perf/builtin-kvm.c +1 -3
        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

Quoted 6 lines
tools/perf/builtin-kvm.c +0 -1
        if (!file_name) {
                file_name = get_filename_for_perf_kvm();
--

2.34.1

#2 lore raw
Quoted 14 lines · Namhyung Kim

Hello,

Quoted 7 lines · On Wed, May 15, 2024 at 12:54 PM <[email protected]> wrote:

From: Yunseong Kim <[email protected]>

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.

Quoted 1 line
Quoted 7 lines
Quoted 3 lines

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.

Quoted 22 lines
Quoted 22 lines
---
 tools/perf/builtin-kvm.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)
tools/perf/builtin-kvm.c +1 -1
index 71165036e4ca..654a07658cdd 100644
@@ -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 };
 
Quoted 15 lines

tools/perf/builtin-kvm.c int cmd_kvm(int argc, const char **argv) · line 2163

Quoted 13 lines
tools/perf/builtin-kvm.c +11 -2
-       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.

Quoted 13 lines

tools/perf/builtin-kvm.c int cmd_kvm(int argc, const char **argv) · line 2162

Quoted 9 lines
tools/perf/builtin-kvm.c +1 -3
        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.

Quoted 7 lines

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

Quoted 6 lines
Quoted 6 lines
tools/perf/builtin-kvm.c +0 -1
        if (!file_name) {
                file_name = get_filename_for_perf_kvm();
--

2.34.1