On Sun, Sep 28, 2014 at 07:39:57AM +0000, Zhang, Jerry wrote:
> 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.
>
The function you reference is meant to assert that all the cpu features that
were enabled during the build are supported on the processor. I expect you
enabled the crypto test, and as such the AES instructions were enabled in the
build. disable the examples build and you'll probably be ok.
Neil
> 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);
> }
> }
> }
