passt, pasta: Run-time selection of AVX2 build

Build-time selection of AVX2 flags and routines is not practical for
distributions, but limiting AVX2 usage to checksum routines with
specific run-time detection doesn't allow for easy performance gains
from auto-vectorisation of batched packet handling routines.

For x86_64, build non-AVX2 and AVX2 binaries, and implement a simple
wrapper replacing the current executable with the AVX2 build if it's
available, and if AVX2 is supported by the current CPU.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/passt.c b/passt.c
index e7dd108..40d3e57 100644
--- a/passt.c
+++ b/passt.c
@@ -69,6 +69,7 @@
 #include "tap.h"
 #include "conf.h"
 #include "pasta.h"
+#include "arch.h"
 
 #define EPOLL_EVENTS		8
 
@@ -313,6 +314,8 @@ int main(int argc, char **argv)
 	struct sigaction sa;
 	char *log_name;
 
+	arch_avx2_exec(argv);
+
 	check_root();
 	drop_caps();