[PATCH] Error reporting improvement

[PATCH] Error reporting improvement

[Adrien BAK]

In the current version, when using perf record, if something goes wrong in
tools/perf/builtin-record.c:375  session = perf_session__new(file, 
false, NULL);
The error message:
"Not enough memory for reading per file header"
is issued. This error message seems to be outdated and is not very helpful.
This patch propose to replace this error message by
"Perf session creation failed"

I believe this issue has been brought to lkml :
https://lkml.org/lkml/2014/2/24/458
although this patch only tackle a (small) part of the issue.

Additionnaly, this patch improves error reporting in
tools/perf/util/data.c open_file_write
Currently, if the call to open fails, the user is unaware of it.
This patch logs the error, before returning the error code to the caller.

Signed-off-by: Adrien BAK <adrien.bak@metascale.org>

---
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index eb524f9..8ce62ef 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -374,7 +374,7 @@ static int __cmd_record(struct record *rec, int 
argc, const char **argv)

      session = perf_session__new(file, false, NULL);
      if (session == NULL) {
-        pr_err("Not enough memory for reading perf file header\n");
+        pr_err("Perf session creation failed.\n");
          return -1;
      }

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 1fbcd8b..ff2ced7 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -86,10 +86,16 @@ static int open_file_read(struct perf_data_file *file)

  static int open_file_write(struct perf_data_file *file)
  {
+    int fd;
      if (check_backup(file))
          return -1;

-    return open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
+    fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
+
+    if (fd < 0)
+        pr_err("failed to open %s : %s\n", file->path, strerror(errno));
+
+    return fd;
  }

  static int open_file(struct perf_data_file *file)

Re: [PATCH] Error reporting improvement

[Will Deacon]

Hi Adrien,

On Wed, Apr 16, 2014 at 08:32:37AM +0100, Adrien BAK wrote:
> In the current version, when using perf record, if something goes wrong in
> tools/perf/builtin-record.c:375  session = perf_session__new(file, 
> false, NULL);
> The error message:
> "Not enough memory for reading per file header"
> is issued. This error message seems to be outdated and is not very helpful.
> This patch propose to replace this error message by
> "Perf session creation failed"
> 
> I believe this issue has been brought to lkml :
> https://lkml.org/lkml/2014/2/24/458
> although this patch only tackle a (small) part of the issue.
> 
> Additionnaly, this patch improves error reporting in
> tools/perf/util/data.c open_file_write
> Currently, if the call to open fails, the user is unaware of it.
> This patch logs the error, before returning the error code to the caller.
> 
> Signed-off-by: Adrien BAK <adrien.bak@metascale.org>

Whilst this patch (admittedly) only solves part of the problem, I think it
makes the error I encountered a lot easier to understand.

Thanks,

  Reported-by: Will Deacon <will.deacon@arm.com>

Will

> 
> ---
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index eb524f9..8ce62ef 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -374,7 +374,7 @@ static int __cmd_record(struct record *rec, int 
> argc, const char **argv)
> 
>       session = perf_session__new(file, false, NULL);
>       if (session == NULL) {
> -        pr_err("Not enough memory for reading perf file header\n");
> +        pr_err("Perf session creation failed.\n");
>           return -1;
>       }
> 
> diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> index 1fbcd8b..ff2ced7 100644
> --- a/tools/perf/util/data.c
> +++ b/tools/perf/util/data.c
> @@ -86,10 +86,16 @@ static int open_file_read(struct perf_data_file *file)
> 
>   static int open_file_write(struct perf_data_file *file)
>   {
> +    int fd;
>       if (check_backup(file))
>           return -1;
> 
> -    return open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
> +    fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
> +
> +    if (fd < 0)
> +        pr_err("failed to open %s : %s\n", file->path, strerror(errno));
> +
> +    return fd;
>   }
> 
>   static int open_file(struct perf_data_file *file)
> 
> 

Re: [PATCH] Error reporting improvement

[Jiri Olsa]

On Wed, Apr 16, 2014 at 03:24:05PM +0100, Will Deacon wrote:
> Hi Adrien,
> 
> On Wed, Apr 16, 2014 at 08:32:37AM +0100, Adrien BAK wrote:
> > In the current version, when using perf record, if something goes wrong in
> > tools/perf/builtin-record.c:375  session = perf_session__new(file, 
> > false, NULL);
> > The error message:
> > "Not enough memory for reading per file header"
> > is issued. This error message seems to be outdated and is not very helpful.
> > This patch propose to replace this error message by
> > "Perf session creation failed"
> > 
> > I believe this issue has been brought to lkml :
> > https://lkml.org/lkml/2014/2/24/458
> > although this patch only tackle a (small) part of the issue.
> > 
> > Additionnaly, this patch improves error reporting in
> > tools/perf/util/data.c open_file_write
> > Currently, if the call to open fails, the user is unaware of it.
> > This patch logs the error, before returning the error code to the caller.
> > 
> > Signed-off-by: Adrien BAK <adrien.bak@metascale.org>
> 
> Whilst this patch (admittedly) only solves part of the problem, I think it
> makes the error I encountered a lot easier to understand.
> 
> Thanks,
> 
>   Reported-by: Will Deacon <will.deacon@arm.com>

seems ok to me, but the patch is mangled:

[jolsa@krava perf]$ git am /tmp/b
Applying: Error reporting improvement
fatal: corrupt patch at line 7
Patch failed at 0001 Error reporting improvement
The copy of the patch that failed is found in:
   /home/jolsa/kernel.org/linux-perf/.git/rebase-apply/patch
When you have resolved this problem, run "git am --resolved".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

[jolsa@krava perf]$ patch -p3 < /tmp/b1 
patching file builtin-record.c
patch: **** malformed patch at line 87: argc, const char **argv)

please check Documentation/email-clients.txt and resend

thanks,
jirka

> 
> Will
> 
> > 
> > ---
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index eb524f9..8ce62ef 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -374,7 +374,7 @@ static int __cmd_record(struct record *rec, int 
> > argc, const char **argv)
> > 
> >       session = perf_session__new(file, false, NULL);
> >       if (session == NULL) {
> > -        pr_err("Not enough memory for reading perf file header\n");
> > +        pr_err("Perf session creation failed.\n");
> >           return -1;
> >       }
> > 
> > diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> > index 1fbcd8b..ff2ced7 100644
> > --- a/tools/perf/util/data.c
> > +++ b/tools/perf/util/data.c
> > @@ -86,10 +86,16 @@ static int open_file_read(struct perf_data_file *file)
> > 
> >   static int open_file_write(struct perf_data_file *file)
> >   {
> > +    int fd;
> >       if (check_backup(file))
> >           return -1;
> > 
> > -    return open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
> > +    fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
> > +
> > +    if (fd < 0)
> > +        pr_err("failed to open %s : %s\n", file->path, strerror(errno));
> > +
> > +    return fd;
> >   }
> > 
> >   static int open_file(struct perf_data_file *file)
> > 
> > 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html