Hi Arnaldo, Adrian,
On Mon, Jul 12, 2021 at 03:14:35PM -0300, Arnaldo Carvalho de Melo wrote:
Em Sun, Jul 11, 2021 at 06:41:04PM +0800, Leo Yan escreveu:
It's useful to know that the kernel is running in 32-bit or 64-bit mode. E.g. We can decide if perf tool is running in compat mode from this info.
This patch adds a global variable "kernel_is_64_bit", it's initialized when a session setups environment, its value is decided by checking the architecture string.
Signed-off-by: Leo Yan leo.yan@linaro.org
tools/perf/util/env.c | 17 ++++++++++++++++- tools/perf/util/env.h | 1 + 2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c index ebc5e9ad35db..345635a2e842 100644 --- a/tools/perf/util/env.c +++ b/tools/perf/util/env.c @@ -11,6 +11,7 @@ #include <stdlib.h> #include <string.h> +int kernel_is_64_bit; struct perf_env perf_env;
Why can't this be in 'struct perf_env'?
Good question. I considered to add it in struct perf_env but finally I used this way; the reason is this variable "kernel_is_64_bit" is only used during recording phase for AUX ring buffer, and don't use it for report. So seems to me it's over complexity to add a new field and just wander if it's necessary to save this field as new feature in the perf header.
Combining the comment from Adrian in another email, I think it's good to add a new field "compat_mode" in the struct perf_env, and this field will be initialized in build-record.c. Currently we don't need to save this value into the perf file, if later we need to use this value for decoding phase, then we can add a new feature item to save "compat_mode" into the perf file's header.
If you have any different idea, please let me know. Thanks!
Leo