[dpdk-dev] [PATCH] eal: check cpu flags at init
Aaron Conole
aconole at redhat.com
Mon Sep 26 17:43:37 CEST 2016
Flavio Leitner <fbl at sysclose.org> writes:
> An application might be linked to DPDK but not really use it,
> so move the cpu flag check to the EAL initialization instead.
>
> Signed-off-by: Flavio Leitner <fbl at sysclose.org>
> ---
> lib/librte_eal/bsdapp/eal/eal.c | 3 +++
> lib/librte_eal/common/eal_common_cpuflags.c | 6 ------
> lib/librte_eal/linuxapp/eal/eal.c | 3 +++
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
> index a0c8f8c..c4b22af 100644
> --- a/lib/librte_eal/bsdapp/eal/eal.c
> +++ b/lib/librte_eal/bsdapp/eal/eal.c
> @@ -496,6 +496,9 @@ rte_eal_init(int argc, char **argv)
> char cpuset[RTE_CPU_AFFINITY_STR_LEN];
> char thread_name[RTE_MAX_THREAD_NAME_LEN];
>
> + /* checks if the machine is adequate */
> + rte_cpu_check_supported();
> +
I think it makes sense to return a result here; after all, since this
is no longer a *constructor*, we can actually handle a failure case.
So maybe the following diff:
diff --git a/lib/librte_eal/common/eal_common_cpuflags.c b/lib/librte_eal/common/eal_common_cpuflags.c
index ecb1240..eccf5f8 100644
--- a/lib/librte_eal/common/eal_common_cpuflags.c
+++ b/lib/librte_eal/common/eal_common_cpuflags.c
@@ -38,15 +38,9 @@
/**
* Checks if the machine is adequate for running the binary. If it is not, the
- * program exits with status 1.
- * The function attribute forces this function to be called before main(). But
- * with ICC, the check is generated by the compiler.
+ * function returns ENOTSUP.
*/
-#ifndef __INTEL_COMPILER
-void __attribute__ ((__constructor__))
-#else
-void
-#endif
+int
rte_cpu_check_supported(void)
{
/* This is generated at compile-time by the build system */
@@ -63,14 +57,15 @@ rte_cpu_check_supported(void)
fprintf(stderr,
"ERROR: CPU feature flag lookup failed with error %d\n",
ret);
- exit(1);
+ return ENOTSUP;
}
if (!ret) {
fprintf(stderr,
"ERROR: This system does not support \"%s\".\n"
"Please check that RTE_MACHINE is set correctly.\n",
rte_cpu_get_flag_name(compile_time_flags[i]));
- exit(1);
+ return ENOTSUP;
}
}
+ return 0;
}
diff --git a/lib/librte_eal/common/include/generic/rte_cpuflags.h b/lib/librte_eal/common/include/generic/rte_cpuflags.h
index 71321f3..6e4eb5a 100644
--- a/lib/librte_eal/common/include/generic/rte_cpuflags.h
+++ b/lib/librte_eal/common/include/generic/rte_cpuflags.h
@@ -79,7 +79,7 @@ rte_cpu_get_flag_enabled(enum rte_cpu_flag_t feature);
* that were specified at compile time. It is called automatically within the
* EAL, so does not need to be used by applications.
*/
-void
+int
rte_cpu_check_supported(void);
#endif /* _RTE_CPUFLAGS_H_ */
--
and the change these hunks to:
if (!rte_cpu_check_supported()) {
return -1;
}
My only concern is whether this change would be considered ABI
breaking. I wouldn't think so, since it doesn't seem as though an
application would want to call this explicitly (and is spelled out as
such), but I can't be sure that it isn't already included in the
standard application API, and therefore needs to go through the change
process.
My $.02
-Aaron
> if (!rte_atomic32_test_and_set(&run_once))
> return -1;
>
> diff --git a/lib/librte_eal/common/eal_common_cpuflags.c b/lib/librte_eal/common/eal_common_cpuflags.c
> index ecb1240..b5f76f7 100644
> --- a/lib/librte_eal/common/eal_common_cpuflags.c
> +++ b/lib/librte_eal/common/eal_common_cpuflags.c
> @@ -39,14 +39,8 @@
> /**
> * Checks if the machine is adequate for running the binary. If it is not, the
> * program exits with status 1.
> - * The function attribute forces this function to be called before main(). But
> - * with ICC, the check is generated by the compiler.
> */
> -#ifndef __INTEL_COMPILER
> -void __attribute__ ((__constructor__))
> -#else
> void
> -#endif
> rte_cpu_check_supported(void)
> {
> /* This is generated at compile-time by the build system */
> diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
> index d5b81a3..4e88cfc 100644
> --- a/lib/librte_eal/linuxapp/eal/eal.c
> +++ b/lib/librte_eal/linuxapp/eal/eal.c
> @@ -740,6 +740,9 @@ rte_eal_init(int argc, char **argv)
> char cpuset[RTE_CPU_AFFINITY_STR_LEN];
> char thread_name[RTE_MAX_THREAD_NAME_LEN];
>
> + /* checks if the machine is adequate */
> + rte_cpu_check_supported();
> +
> if (!rte_atomic32_test_and_set(&run_once))
> return -1;
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