[Mesa-dev] [PATCH 2/2] swr: allow a single swr architecture to be builtin

[Cherniak, Bruce]

Thanks Chuck!
Reviewed-by: Bruce Cherniak <bruce.cherniak at intel.com>

> On Jan 18, 2018, at 1:57 PM, Chuck Atkins <chuck.atkins at kitware.com> wrote:
> 
> Part 2 of 2 (part 1 is autoconf changes, part 2 is C++ changes)
> 
> When only a single SWR architecture is being used, this allows that
> architecture to be builtin rather than as a separate libswrARCH.so that
> gets loaded via dlopen.  Since there are now several different code
> paths for each detected CPU architecture, the log output is also
> adjusted to convey where the backend is getting loaded from.
> 
> This allows SWR to be used for static mesa builds which are still
> important for large HPC environments where shared libraries can impose
> unacceptable application startup times as hundreds of thousands of copies
> of the libs are loaded from a shared parallel filesystem.
> 
> Based on an initial implementation by Tim Rowley.
> 
> v2: Refactor repetitive preprocessor checks to reduce code duplication
> v3: Formatting changes per Bruce C. Also delay screen creation until end
>    to avoid leaks when failure conditions are hit.
> 
> Signed-off-by: Chuck Atkins <chuck.atkins at kitware.com>
> Reviewed-by: Bruce Cherniak <bruce.cherniak at intel.com>
> CC: Tim Rowley <timothy.o.rowley at intel.com>
> ---
> src/gallium/drivers/swr/swr_loader.cpp | 84 ++++++++++++++++++++--------------
> 1 file changed, 49 insertions(+), 35 deletions(-)
> 
> diff --git a/src/gallium/drivers/swr/swr_loader.cpp b/src/gallium/drivers/swr/swr_loader.cpp
> index 9d6f918e34..7f28bdb536 100644
> --- a/src/gallium/drivers/swr/swr_loader.cpp
> +++ b/src/gallium/drivers/swr/swr_loader.cpp
> @@ -28,81 +28,95 @@
> 
> #include <stdio.h>
> 
> +// Helper function to resolve the backend filename based on architecture
> +inline void get_swr_arch_filename(const char arch[], char filename[])
> +{
> +#ifdef HAVE_SWR_BUILTIN
> +   strcpy(filename , "builtin");
> +#else
> +   sprintf(filename, "%sswr%s%s", UTIL_DL_PREFIX, arch, UTIL_DL_EXT);
> +#endif
> +}
> +
> struct pipe_screen *
> swr_create_screen(struct sw_winsys *winsys)
> {
>    char filename[256] = { 0 };
> -   fprintf(stderr, "SWR detected ");
> -
> -   util_dl_library *pLibrary = nullptr;
> +   bool found = false;
> +   bool is_knl = false;
> +   PFNSwrGetInterface pfnSwrGetInterface = nullptr;
> 
>    util_cpu_detect();
> 
> -   bool is_knl = false;
> -
> -   if (!strlen(filename) &&
> -       util_cpu_caps.has_avx512f && util_cpu_caps.has_avx512er) {
> -#if HAVE_SWR_KNL
> -      fprintf(stderr, "KNL ");
> -      sprintf(filename, "%s%s%s", UTIL_DL_PREFIX, "swrKNL", UTIL_DL_EXT);
> -      is_knl = true;
> +   if (!found && util_cpu_caps.has_avx512f && util_cpu_caps.has_avx512er) {
> +      fprintf(stderr, "SWR detected KNL instruction support ");
> +#ifndef HAVE_SWR_KNL
> +      fprintf(stderr, "(skipping not built).\n");
> #else
> -      fprintf(stderr, "KNL (not built) ");
> +      get_swr_arch_filename("KNL", filename);
> +      found = true;
> +      is_knl = true;
> #endif
>    }
> 
> -   if (!strlen(filename) &&
> -       util_cpu_caps.has_avx512f && util_cpu_caps.has_avx512bw) {
> -#if HAVE_SWR_SKX
> -      fprintf(stderr, "SKX ");
> -      sprintf(filename, "%s%s%s", UTIL_DL_PREFIX, "swrSKX", UTIL_DL_EXT);
> +   if (!found && util_cpu_caps.has_avx512f && util_cpu_caps.has_avx512bw) {
> +      fprintf(stderr, "SWR detected SKX instruction support ");
> +#ifndef HAVE_SWR_SKX
> +      fprintf(stderr, "(skipping not built).\n");
> #else
> -      fprintf(stderr, "SKX (not built) ");
> +      get_swr_arch_filename("SKX", filename);
> +      found = true;
> #endif
>    }
> 
> -   if (!strlen(filename) && util_cpu_caps.has_avx2) {
> -#if HAVE_SWR_AVX2
> -      fprintf(stderr, "AVX2 ");
> -      sprintf(filename, "%s%s%s", UTIL_DL_PREFIX, "swrAVX2", UTIL_DL_EXT);
> +   if (!found && util_cpu_caps.has_avx2) {
> +      fprintf(stderr, "SWR detected AVX2 instruction support ");
> +#ifndef HAVE_SWR_AVX2
> +      fprintf(stderr, "(skipping not built).\n");
> #else
> -      fprintf(stderr, "AVX2 (not built) ");
> +      get_swr_arch_filename("AVX2", filename);
> +      found = true;
> #endif
>    }
> 
> -   if (!strlen(filename) && util_cpu_caps.has_avx) {
> -#if HAVE_SWR_AVX
> -      fprintf(stderr, "AVX ");
> -      sprintf(filename, "%s%s%s", UTIL_DL_PREFIX, "swrAVX", UTIL_DL_EXT);
> +   if (!found && util_cpu_caps.has_avx) {
> +      fprintf(stderr, "SWR detected AVX instruction support ");
> +#ifndef HAVE_SWR_AVX
> +      fprintf(stderr, "(skipping not built).\n");
> #else
> -      fprintf(stderr, "AVX (not built) ");
> +      get_swr_arch_filename("AVX", filename);
> +      found = true;
> #endif
>    }
> 
> -   if (!strlen(filename)) {
> -      fprintf(stderr, "- no appropriate swr architecture library.  Aborting!\n");
> +   if (!found) {
> +      fprintf(stderr, "SWR could not detect a supported CPU architecture.\n");
>       exit(-1);
> -   } else {
> -      fprintf(stderr, "\n");
>    }
> 
> -   pLibrary = util_dl_open(filename);
> +   fprintf(stderr, "(using %s).\n", filename);
> 
> +#ifdef HAVE_SWR_BUILTIN
> +   pfnSwrGetInterface = SwrGetInterface;
> +#else
> +   util_dl_library *pLibrary = util_dl_open(filename);
>    if (!pLibrary) {
>       fprintf(stderr, "SWR library load failure: %s\n", util_dl_error());
>       exit(-1);
>    }
> 
>    util_dl_proc pApiProc = util_dl_get_proc_address(pLibrary, "SwrGetInterface");
> -
>    if (!pApiProc) {
>       fprintf(stderr, "SWR library search failure: %s\n", util_dl_error());
>       exit(-1);
>    }
> 
> +   pfnSwrGetInterface = (PFNSwrGetInterface)pApiProc;
> +#endif
> +
>    struct pipe_screen *screen = swr_create_screen_internal(winsys);
> -   swr_screen(screen)->pfnSwrGetInterface = (PFNSwrGetInterface)pApiProc;
>    swr_screen(screen)->is_knl = is_knl;
> +   swr_screen(screen)->pfnSwrGetInterface = pfnSwrGetInterface;
> 
>    return screen;
> }
> -- 
> 2.14.3
> 
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