On Wed, Jun 22, 2016 at 01:04:41PM +0100, Emil Velikov wrote:
> From: Emil Velikov <emil.veli...@collabora.com>
>
> Do not rely on the git sha1:
> - its current truncated form makes it less unique
> - it does not attribute for local (Vulkand or otherwise) changes
>
> Use a timestamp produced at the time of build. It's perfectly unique,
> unless someone explicitly thinkers with their system clock. Even then
> chances of producing the exact same one are very small, if not zero.
>
> Cc: Jason Ekstrand <ja...@jlekstrand.net>
> Cc: mesa-sta...@lists.freedesktop.org
> Signed-off-by: Emil Velikov <emil.veli...@collabora.com>
> ---
> Current approach uses seconds since Epoch, but if people prefer we
> can use nano seconds, combination of the two and/or other.
> ---
> src/intel/vulkan/.gitignore | 2 ++
> src/intel/vulkan/Makefile.am | 15 ++++++++++++++-
> src/intel/vulkan/anv_device.c | 4 ++--
> 3 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/src/intel/vulkan/.gitignore b/src/intel/vulkan/.gitignore
> index a496146..7ef6a48 100644
> --- a/src/intel/vulkan/.gitignore
> +++ b/src/intel/vulkan/.gitignore
> @@ -2,3 +2,5 @@
> /anv_entrypoints.c
> /anv_entrypoints.h
> /dev_icd.json
> +/anv_timestamp.h.tmp
> +/anv_timestamp.h
> diff --git a/src/intel/vulkan/Makefile.am b/src/intel/vulkan/Makefile.am
> index 4d9ff90..8332ae5 100644
> --- a/src/intel/vulkan/Makefile.am
> +++ b/src/intel/vulkan/Makefile.am
> @@ -131,7 +131,20 @@ anv_entrypoints.c : anv_entrypoints_gen.py
> $(vulkan_include_HEADERS)
> $(AM_V_GEN) cat $(vulkan_include_HEADERS) |\
> $(PYTHON2) $(srcdir)/anv_entrypoints_gen.py code > $@
>
> -BUILT_SOURCES = $(VULKAN_GENERATED_FILES)
> +
> +.PHONY: anv_timestamp.h.tmp
> +anv_timestamp.h.tmp:
> + $(AM_V_GEN) echo "#define ANV_TIMESTAMP `date +%s`" > $@
> +
> +anv_timestamp.h: anv_timestamp.h.tmp
> + @echo "Updating anv_timestamp.h"
> + @if ! cmp -s anv_timestamp.h.tmp anv_timestamp.h; then \
> + mv anv_timestamp.h.tmp anv_timestamp.h ;\
> + else \
> + rm anv_timestamp.h.tmp ;\
> + fi
For the else branch to be taken, the target would have to be generated
twice within the same second, and I don't see why we would want to avoid
modifying anv_timestamp.h's timestamp in this case, since that would be
the only thing that would be changed, and said timestamp would be within
the same second anyway.
I suggest to drop the `if` and unconditionally do the move.
Since this wouldn't change the behaviour anyway, with or without my
suggestion this patch is:
Reviewed-by: Eric Engestrom <eric.engest...@imgtec.com>
> +
> +BUILT_SOURCES = $(VULKAN_GENERATED_FILES) anv_timestamp.h
> CLEANFILES = $(BUILT_SOURCES) dev_icd.json
> EXTRA_DIST = \
> $(top_srcdir)/include/vulkan/vk_icd.h \
> diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
> index 97300c3..e395b1c 100644
> --- a/src/intel/vulkan/anv_device.c
> +++ b/src/intel/vulkan/anv_device.c
> @@ -28,7 +28,7 @@
> #include <fcntl.h>
>
> #include "anv_private.h"
> -#include "git_sha1.h"
> +#include "anv_timestamp.h"
> #include "util/strtod.h"
> #include "util/debug.h"
>
> @@ -426,7 +426,7 @@ void
> anv_device_get_cache_uuid(void *uuid)
> {
> memset(uuid, 0, VK_UUID_SIZE);
> - snprintf(uuid, VK_UUID_SIZE, "anv-%s", MESA_GIT_SHA1 + 4);
> + snprintf(uuid, VK_UUID_SIZE, "anv-%s", ANV_TIMESTAMP);
> }
>
> void anv_GetPhysicalDeviceProperties(
> --
> 2.8.2
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