[dpdk-dev] DPDK cpuflag check failure

[Zhang, Jerry]

Hi all, 

        Do you know why DPDK(shared library) constructor function 
rte_cpu_check_supported() needs to check some unnecessary CPU flags which is 
not used by current DPDK such as "AES"?

    On Hehalem platform with GCC4.8, using shard DPDK library, it will report 
AES is not supported. But actually AES instructions is not used by current DPDK.

    Thanks!

#ifndef __INTEL_COMPILER
void __attribute__ ((__constructor__))
#else
void
#endif
rte_cpu_check_supported(void)
{
        /* This is generated at compile-time by the build system */
        static const enum rte_cpu_flag_t compile_time_flags[] = {
                        RTE_COMPILE_TIME_CPUFLAGS
        };
        unsigned i;
        int ret;

        for (i = 0; i < 
sizeof(compile_time_flags)/sizeof(compile_time_flags[0]); i++) {
                ret = rte_cpu_get_flag_enabled(compile_time_flags[i]);

                if (ret < 0) {
                        fprintf(stderr,
                                "ERROR: CPU feature flag lookup failed with 
error %d\n",
                                ret);
                        exit(1);
                }
                if (!ret) {
                        fprintf(stderr,
                                "ERROR: This system does not support \"%s\".\n"
                                "Please check that RTE_MACHINE is set 
correctly.\n",
                                cpu_feature_table[compile_time_flags[i]].name);
                        exit(1);
                }
        }
}