diff mbox series

[v3] plugins/syscall: Added a table-like summary output

Message ID 20210420115433.12148-1-ma.mandourr@gmail.com (mailing list archive)
State New
Headers show
Series [v3] plugins/syscall: Added a table-like summary output | expand

Commit Message

Mahmoud Mandour April 20, 2021, 11:54 a.m. UTC
Added a table-like output which contains the total number of calls
for each used syscall along with the number of errors that occurred.

Per-call tracing is still available through supplying the argument
``print`` to the plugin.

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
---
v2 -> v3: * Locked shared hash-table to protect access across multiple
          callback invocations.
          * Used better variable names for the hash table and entries.
          * Factored the creation and looking-up for hash table entries.
          * Eliminated the usage of a global boolean and checked against
          the existence of the ``statistics`` hash-table. (it's allocated
          only if the plugin in the summary(default) mode.
          * Removed the function ``free_entry`` and passed ``g_free``
          directly to ``g_hash_table_new_full()``.

 tests/plugin/syscall.c | 98 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 93 insertions(+), 5 deletions(-)

Comments

Alex Bennée May 5, 2021, 1:13 p.m. UTC | #1
Mahmoud Mandour <ma.mandourr@gmail.com> writes:

> Added a table-like output which contains the total number of calls
> for each used syscall along with the number of errors that occurred.
>
> Per-call tracing is still available through supplying the argument
> ``print`` to the plugin.
>
> Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
> ---
<snip>
> +
> +void print_entry(gpointer val, gpointer user_data)
>  {
>      g_autofree gchar *out;
> -    out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
> -            num, ret);
> +    SyscallStats *entry = (SyscallStats *) val;
> +    int64_t syscall_num = entry->num;
> +    out = g_strdup_printf(
> +        "%-13" PRIi64 "%-6" PRIi64 " %" PRIi64 "\n",
> +        syscall_num, entry->calls, entry->errors);
>      qemu_plugin_outs(out);
>  }

This still fails to compile due to a missing static:

[2/10] Compiling C object tests/plugin/libsyscall.so.p/syscall.c.o
FAILED: tests/plugin/libsyscall.so.p/syscall.c.o
cc -Itests/plugin/libsyscall.so.p -Itests/plugin -I../../tests/plugin -I../../include/qemu -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -fdiagnostics-color=auto -pipe -Wall -Winvalid-pch -Werror -std=gnu99 -O2 -g -isystem /home/alex/lsrc/qemu.git/linux-headers -isystem linux-headers -iquote . -iquote /home/alex/lsrc/qemu.git -iquote /home/alex/lsrc/qemu.git/include -iquote /home/alex/lsrc/qemu.git/disas/libvixl -iquote /home/alex/lsrc/qemu.git/tcg/i386 -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -DLEGACY_RDMA_REG_MR -fPIC -MD -MQ tests/plugin/libsyscall.so.p/syscall.c.o -MF tests/plugin/libsyscall.so.p/syscall.c.o.d -o tests/plugin/libsyscall.so.p/syscall.c.o -c ../../tests/plugin/syscall.c
../../tests/plugin/syscall.c:80:6: error: no previous prototype for ‘print_entry’ [-Werror=missing-prototypes]
 void print_entry(gpointer val, gpointer user_data)
      ^~~~~~~~~~~
cc1: all warnings being treated as errors
ninja: build stopped: subcommand failed.
make: *** [Makefile:152: run-ninja] Error 1

>  
> +static gint comp_func(gconstpointer ea, gconstpointer eb)
> +{
> +    SyscallStats *ent_a = (SyscallStats *) ea;
> +    SyscallStats *ent_b = (SyscallStats *) eb;
> +
> +    return ent_a->calls > ent_b->calls ? -1 : 1;
> +}
> +
>  /* ************************************************************************* */
> +static void plugin_exit(qemu_plugin_id_t id, void *p)
> +{
> +    if (!statistics) {
> +        return;
> +    }
> +
> +    g_mutex_lock(&lock);
> +    GList *entries = g_hash_table_get_values(statistics);
> +    entries = g_list_sort(entries, comp_func);
> +    qemu_plugin_outs("syscall no.  calls  errors\n");
>  
> -static void plugin_exit(qemu_plugin_id_t id, void *p) {}
> +    g_list_foreach(entries, print_entry, NULL);
> +
> +    g_list_free(entries);
> +    g_hash_table_destroy(statistics);
> +    g_mutex_unlock(&lock);
> +}

Hmm it looks like we see multiple plugin_exit's when running multiple
threads:

  ./qemu-aarch64 -d plugin -D output -plugin ./tests/plugin/libsyscall.so ./tests/tcg/aarch64-linux-user/linux-test

I don't see it with testthread or the new signals test though which is
confusing. Something linux-test is doing must be different.

>  
>  QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
>                                             const qemu_info_t *info,
>                                             int argc, char **argv)
>  {
> +    if (argc == 0) {
> +        statistics = g_hash_table_new_full(NULL, g_direct_equal, NULL, g_free);
> +    } else {
> +        for (int i = 0; i < argc; i++) {
> +            if (g_strcmp0(argv[i], "print") != 0) {
> +                fprintf(stderr, "unsupported argument: %s\n", argv[i]);
> +                return -1;
> +            }
> +        }
> +    }
> +
>      qemu_plugin_register_vcpu_syscall_cb(id, vcpu_syscall);
>      qemu_plugin_register_vcpu_syscall_ret_cb(id, vcpu_syscall_ret);
>      qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);

Otherwise looking pretty good - certainly a more useful default ;-)

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Mahmoud Mandour May 5, 2021, 5:56 p.m. UTC | #2
On Wed, May 5, 2021 at 3:19 PM Alex Bennée <alex.bennee@linaro.org> wrote:

>
> Mahmoud Mandour <ma.mandourr@gmail.com> writes:
>
> > Added a table-like output which contains the total number of calls
> > for each used syscall along with the number of errors that occurred.
> >
> > Per-call tracing is still available through supplying the argument
> > ``print`` to the plugin.
> >
> > Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
> > ---
> <snip>
> > +
> > +void print_entry(gpointer val, gpointer user_data)
> >  {
> >      g_autofree gchar *out;
> > -    out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64
> "\n",
> > -            num, ret);
> > +    SyscallStats *entry = (SyscallStats *) val;
> > +    int64_t syscall_num = entry->num;
> > +    out = g_strdup_printf(
> > +        "%-13" PRIi64 "%-6" PRIi64 " %" PRIi64 "\n",
> > +        syscall_num, entry->calls, entry->errors);
> >      qemu_plugin_outs(out);
> >  }
>
> This still fails to compile due to a missing static:
>
> [2/10] Compiling C object tests/plugin/libsyscall.so.p/syscall.c.o
> FAILED: tests/plugin/libsyscall.so.p/syscall.c.o
> cc -Itests/plugin/libsyscall.so.p -Itests/plugin -I../../tests/plugin
> -I../../include/qemu -I/usr/include/glib-2.0
> -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -fdiagnostics-color=auto -pipe
> -Wall -Winvalid-pch -Werror -std=gnu99 -O2 -g -isystem
> /home/alex/lsrc/qemu.git/linux-headers -isystem linux-headers -iquote .
> -iquote /home/alex/lsrc/qemu.git -iquote /home/alex/lsrc/qemu.git/include
> -iquote /home/alex/lsrc/qemu.git/disas/libvixl -iquote
> /home/alex/lsrc/qemu.git/tcg/i386 -pthread -U_FORTIFY_SOURCE
> -D_FORTIFY_SOURCE=2 -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64
> -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef
> -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common
> -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits
> -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
> -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined
> -Wimplicit-fallthrough=2 -Wno-missing-include-dirs
> -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong
> -DLEGACY_RDMA_REG_MR -fPIC -MD -MQ tests/plugin/libsyscall.so.p/syscall.c.o
> -MF tests/plugin/libsyscall.so.p/syscall.c.o.d -o
> tests/plugin/libsyscall.so.p/syscall.c.o -c ../../tests/plugin/syscall.c
> ../../tests/plugin/syscall.c:80:6: error: no previous prototype for
> ‘print_entry’ [-Werror=missing-prototypes]
>  void print_entry(gpointer val, gpointer user_data)
>       ^~~~~~~~~~~
> cc1: all warnings being treated as errors
> ninja: build stopped: subcommand failed.
> make: *** [Makefile:152: run-ninja] Error 1
>
> Thanks for the notice. I got it working because I was building it using
the makefile in the
contrib/plugins makefile and it does not report warnings. I fixed it.

> >
> > +static gint comp_func(gconstpointer ea, gconstpointer eb)
> > +{
> > +    SyscallStats *ent_a = (SyscallStats *) ea;
> > +    SyscallStats *ent_b = (SyscallStats *) eb;
> > +
> > +    return ent_a->calls > ent_b->calls ? -1 : 1;
> > +}
> > +
> >  /*
> ************************************************************************* */
> > +static void plugin_exit(qemu_plugin_id_t id, void *p)
> > +{
> > +    if (!statistics) {
> > +        return;
> > +    }
> > +
> > +    g_mutex_lock(&lock);
> > +    GList *entries = g_hash_table_get_values(statistics);
> > +    entries = g_list_sort(entries, comp_func);
> > +    qemu_plugin_outs("syscall no.  calls  errors\n");
> >
> > -static void plugin_exit(qemu_plugin_id_t id, void *p) {}
> > +    g_list_foreach(entries, print_entry, NULL);
> > +
> > +    g_list_free(entries);
> > +    g_hash_table_destroy(statistics);
> > +    g_mutex_unlock(&lock);
> > +}
>
> Hmm it looks like we see multiple plugin_exit's when running multiple
> threads:
>
>   ./qemu-aarch64 -d plugin -D output -plugin ./tests/plugin/libsyscall.so
> ./tests/tcg/aarch64-linux-user/linux-test
>
> I don't see it with testthread or the new signals test though which is
> confusing. Something linux-test is doing must be different.
>

The output of other plugins is similar so apparently there's something
different with linux-test, yes.

Since this is not a bug related to this particular patch, should I fix the
compilation error and resend the patch?


>
> >
> >  QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
> >                                             const qemu_info_t *info,
> >                                             int argc, char **argv)
> >  {
> > +    if (argc == 0) {
> > +        statistics = g_hash_table_new_full(NULL, g_direct_equal, NULL,
> g_free);
> > +    } else {
> > +        for (int i = 0; i < argc; i++) {
> > +            if (g_strcmp0(argv[i], "print") != 0) {
> > +                fprintf(stderr, "unsupported argument: %s\n", argv[i]);
> > +                return -1;
> > +            }
> > +        }
> > +    }
> > +
> >      qemu_plugin_register_vcpu_syscall_cb(id, vcpu_syscall);
> >      qemu_plugin_register_vcpu_syscall_ret_cb(id, vcpu_syscall_ret);
> >      qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
>
> Otherwise looking pretty good - certainly a more useful default ;-)
>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>
>
> --
> Alex Bennée
>

Thanks,
Mahmoud
diff mbox series

Patch

diff --git a/tests/plugin/syscall.c b/tests/plugin/syscall.c
index 53ee2ab6c4..7b856f2fe2 100644
--- a/tests/plugin/syscall.c
+++ b/tests/plugin/syscall.c
@@ -16,32 +16,120 @@ 
 
 QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
 
+typedef struct {
+    int64_t num;
+    int64_t calls;
+    int64_t errors;
+} SyscallStats;
+
+static GMutex lock;
+static GHashTable *statistics;
+
+static SyscallStats *get_or_create_entry(int64_t num)
+{
+    SyscallStats *entry =
+        (SyscallStats *) g_hash_table_lookup(statistics, GINT_TO_POINTER(num));
+
+    if (!entry) {
+        entry = g_new0(SyscallStats, 1);
+        entry->num = num;
+        g_hash_table_insert(statistics, GINT_TO_POINTER(num), (gpointer) entry);
+    }
+
+    return entry;
+}
+
 static void vcpu_syscall(qemu_plugin_id_t id, unsigned int vcpu_index,
                          int64_t num, uint64_t a1, uint64_t a2,
                          uint64_t a3, uint64_t a4, uint64_t a5,
                          uint64_t a6, uint64_t a7, uint64_t a8)
 {
-    g_autofree gchar *out = g_strdup_printf("syscall #%" PRIi64 "\n", num);
-    qemu_plugin_outs(out);
+    if (statistics) {
+        SyscallStats *entry;
+        g_mutex_lock(&lock);
+        entry = get_or_create_entry(num);
+        entry->calls++;
+        g_mutex_unlock(&lock);
+    } else {
+        g_autofree gchar *out = g_strdup_printf("syscall #%" PRIi64 "\n", num);
+        qemu_plugin_outs(out);
+    }
 }
 
 static void vcpu_syscall_ret(qemu_plugin_id_t id, unsigned int vcpu_idx,
                              int64_t num, int64_t ret)
+{
+    if (statistics) {
+        SyscallStats *entry;
+
+        g_mutex_lock(&lock);
+        /* Should always return an existent entry. */
+        entry = get_or_create_entry(num);
+        if (ret < 0) {
+            entry->errors++;
+        }
+        g_mutex_unlock(&lock);
+    } else {
+        g_autofree gchar *out;
+        out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
+                num, ret);
+        qemu_plugin_outs(out);
+    }
+}
+
+void print_entry(gpointer val, gpointer user_data)
 {
     g_autofree gchar *out;
-    out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
-            num, ret);
+    SyscallStats *entry = (SyscallStats *) val;
+    int64_t syscall_num = entry->num;
+    out = g_strdup_printf(
+        "%-13" PRIi64 "%-6" PRIi64 " %" PRIi64 "\n",
+        syscall_num, entry->calls, entry->errors);
     qemu_plugin_outs(out);
 }
 
+static gint comp_func(gconstpointer ea, gconstpointer eb)
+{
+    SyscallStats *ent_a = (SyscallStats *) ea;
+    SyscallStats *ent_b = (SyscallStats *) eb;
+
+    return ent_a->calls > ent_b->calls ? -1 : 1;
+}
+
 /* ************************************************************************* */
+static void plugin_exit(qemu_plugin_id_t id, void *p)
+{
+    if (!statistics) {
+        return;
+    }
+
+    g_mutex_lock(&lock);
+    GList *entries = g_hash_table_get_values(statistics);
+    entries = g_list_sort(entries, comp_func);
+    qemu_plugin_outs("syscall no.  calls  errors\n");
 
-static void plugin_exit(qemu_plugin_id_t id, void *p) {}
+    g_list_foreach(entries, print_entry, NULL);
+
+    g_list_free(entries);
+    g_hash_table_destroy(statistics);
+    g_mutex_unlock(&lock);
+}
 
 QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
                                            const qemu_info_t *info,
                                            int argc, char **argv)
 {
+    if (argc == 0) {
+        statistics = g_hash_table_new_full(NULL, g_direct_equal, NULL, g_free);
+    } else {
+        for (int i = 0; i < argc; i++) {
+            if (g_strcmp0(argv[i], "print") != 0) {
+                fprintf(stderr, "unsupported argument: %s\n", argv[i]);
+                return -1;
+            }
+        }
+    }
+
     qemu_plugin_register_vcpu_syscall_cb(id, vcpu_syscall);
     qemu_plugin_register_vcpu_syscall_ret_cb(id, vcpu_syscall_ret);
     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);