2021-09-01 13:59:12

by Artem Bityutskiy

Subject: [PATCH] tracing: synth events: increase max fields count

From: Artem Bityutskiy <[email protected]>

Sometimes it is useful to construct larger synthetic trace events. Increase
'SYNTH_FIELDS_MAX' (maximum number of fields in a synthetic event) from 32 to
64.

Signed-off-by: Artem Bityutskiy <[email protected]>
---
kernel/trace/trace_synth.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_synth.h b/kernel/trace/trace_synth.h
index 4007fe95cf42..b29595fe3ac5 100644
--- a/kernel/trace/trace_synth.h
+++ b/kernel/trace/trace_synth.h
@@ -5,7 +5,7 @@
#include "trace_dynevent.h"

#define SYNTH_SYSTEM "synthetic"
-#define SYNTH_FIELDS_MAX 32
+#define SYNTH_FIELDS_MAX 64

#define STR_VAR_LEN_MAX MAX_FILTER_STR_VAL /* must be multiple of sizeof(u64) */

--
2.31.1

2021-09-02 20:57:29

by Tom Zanussi

Subject: Re: [PATCH] tracing: synth events: increase max fields count

Hi Artem,

On Wed, 2021-09-01 at 16:55 +0300, Artem Bityutskiy wrote:
> From: Artem Bityutskiy <[email protected]>
>
> Sometimes it is useful to construct larger synthetic trace events.
> Increase
> 'SYNTH_FIELDS_MAX' (maximum number of fields in a synthetic event)
> from 32 to
> 64.
>
> Signed-off-by: Artem Bityutskiy <[email protected]>
> ---
> kernel/trace/trace_synth.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace_synth.h b/kernel/trace/trace_synth.h
> index 4007fe95cf42..b29595fe3ac5 100644
> --- a/kernel/trace/trace_synth.h
> +++ b/kernel/trace/trace_synth.h
> @@ -5,7 +5,7 @@
> #include "trace_dynevent.h"
>
> #define SYNTH_SYSTEM "synthetic"
> -#define SYNTH_FIELDS_MAX 32
> +#define SYNTH_FIELDS_MAX 64
>
> #define STR_VAR_LEN_MAX MAX_FILTER_STR_VAL /* must be
> multiple of sizeof(u64) */
>

This looks fine, but it does also bloat the arrays that use it as a
size. There's only one that I'd be worried about, the per-elt
hist_elt_data[] array, but I'll send a patch shortly that gets rid of
that limitation.

Acked-by: Tom Zanussi <[email protected]>

Thanks!

Tom