Re: [PATCH] perf build: Add LIBTRACEEVENT_DIR build option

[Ian Rogers]

On Wed, Mar 13, 2024 at 11:30 PM Yang Jihong <yangjihong@xxxxxxxxxxxxx> wrote:
>
> Currently, when libtraceevent is not linked,
> perf does not support tracepoint:
>
>   # ./perf record -e sched:sched_switch -a sleep 10
>   event syntax error: 'sched:sched_switch'
>                        \___ unsupported tracepoint
>
>   libtraceevent is necessary for tracepoint support
>   Run 'perf list' for a list of valid events
>
>    Usage: perf record [<options>] [<command>]
>       or: perf record [<options>] -- <command> [<options>]
>
>       -e, --event <event>   event selector. use 'perf list' to list available events
>
> For cross-compilation scenario, library may not be installed in the default
> system path. Based on the above requirements, add LIBTRACEEVENT_DIR build
> option to support specifying path of libtraceevent.
>
> Example:
>
>   1. Cross compile libtraceevent
>   # cd /opt/libtraceevent
>   # CROSS_COMPILE=aarch64-linux-gnu- make
>
>   2. Cross compile perf
>   # cd tool/perf
>   # make VF=1 ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- NO_LIBELF=1 LDFLAGS=--static LIBTRACEEVENT_DIR=/opt/libtraceevent
>   <SNIP>
>   Auto-detecting system features:
>   <SNIP>
>   ...                       LIBTRACEEVENT_DIR: /opt/libtraceevent
>
> Signed-off-by: Yang Jihong <yangjihong@xxxxxxxxxxxxx>

This all looks good to me, thanks!

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

> ---
>  tools/perf/Makefile.config | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 1fe8df97fe88..7783479de691 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -182,6 +182,16 @@ endif
>  FEATURE_CHECK_CFLAGS-libzstd := $(LIBZSTD_CFLAGS)
>  FEATURE_CHECK_LDFLAGS-libzstd := $(LIBZSTD_LDFLAGS)
>
> +# for linking with debug library, run like:
> +# make DEBUG=1 LIBTRACEEVENT_DIR=/opt/libtraceevent/
> +TRACEEVENTLIBS := -ltraceevent
> +ifdef LIBTRACEEVENT_DIR
> +  LIBTRACEEVENT_CFLAGS  := -I$(LIBTRACEEVENT_DIR)/include
> +  LIBTRACEEVENT_LDFLAGS := -L$(LIBTRACEEVENT_DIR)/lib
> +endif
> +FEATURE_CHECK_CFLAGS-libtraceevent := $(LIBTRACEEVENT_CFLAGS)
> +FEATURE_CHECK_LDFLAGS-libtraceevent := $(LIBTRACEEVENT_LDFLAGS) $(TRACEEVENTLIBS)
> +
>  FEATURE_CHECK_CFLAGS-bpf = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(SRCARCH)/include/uapi -I$(srctree)/tools/include/uapi
>  # include ARCH specific config
>  -include $(src-perf)/arch/$(SRCARCH)/Makefile
> @@ -1165,9 +1175,10 @@ endif
>  ifneq ($(NO_LIBTRACEEVENT),1)
>    $(call feature_check,libtraceevent)
>    ifeq ($(feature-libtraceevent), 1)
> -    CFLAGS += -DHAVE_LIBTRACEEVENT
> -    EXTLIBS += -ltraceevent
> -    LIBTRACEEVENT_VERSION := $(shell $(PKG_CONFIG) --modversion libtraceevent)
> +    CFLAGS += -DHAVE_LIBTRACEEVENT $(LIBTRACEEVENT_CFLAGS)
> +    LDFLAGS += $(LIBTRACEEVENT_LDFLAGS)
> +    EXTLIBS += ${TRACEEVENTLIBS}
> +    LIBTRACEEVENT_VERSION := $(shell PKG_CONFIG_PATH=$(LIBTRACEEVENT_DIR) $(PKG_CONFIG) --modversion libtraceevent)
>      LIBTRACEEVENT_VERSION_1 := $(word 1, $(subst ., ,$(LIBTRACEEVENT_VERSION)))
>      LIBTRACEEVENT_VERSION_2 := $(word 2, $(subst ., ,$(LIBTRACEEVENT_VERSION)))
>      LIBTRACEEVENT_VERSION_3 := $(word 3, $(subst ., ,$(LIBTRACEEVENT_VERSION)))
> @@ -1175,7 +1186,7 @@ ifneq ($(NO_LIBTRACEEVENT),1)
>      CFLAGS += -DLIBTRACEEVENT_VERSION=$(LIBTRACEEVENT_VERSION_CPP)
>      $(call detected,CONFIG_LIBTRACEEVENT)
>    else
> -    $(error ERROR: libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel or build with NO_LIBTRACEEVENT=1)
> +    $(error ERROR: libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel and/or set LIBTRACEEVENT_DIR or build with NO_LIBTRACEEVENT=1)
>    endif
>
>    $(call feature_check,libtracefs)
> @@ -1301,6 +1312,7 @@ ifeq ($(VF),1)
>    $(call print_var,LIBUNWIND_DIR)
>    $(call print_var,LIBDW_DIR)
>    $(call print_var,JDIR)
> +  $(call print_var,LIBTRACEEVENT_DIR)
>
>    ifeq ($(dwarf-post-unwind),1)
>      $(call feature_print_text,"DWARF post unwind library", $(dwarf-post-unwind-text)) $(info $(MSG))
> --
> 2.25.1
>