This commit implements a method to retrieve the
CPU ISA capabilities, and allows each DPCLS implementation
to use these ISA capabilities to decide if the specific
implemenation is a valid candidate for the CPU.
Please note this is a POC patch only, the actual generic
code here can always run. Future DPCLS implementations may
require specific ISA, which is what this patch enables.
Signed-off-by: Harry van Haaren <harry.van.haa...@intel.com>
---
lib/dpdk-stub.c | 11 +++++++++++
lib/dpdk.c | 16 ++++++++++++++++
lib/dpdk.h | 7 +++++++
lib/dpif-netdev-lookup-generic.c | 7 +++++++
4 files changed, 41 insertions(+)
diff --git a/lib/dpdk-stub.c b/lib/dpdk-stub.c
index c332c217c..0aaccd983 100644
--- a/lib/dpdk-stub.c
+++ b/lib/dpdk-stub.c
@@ -79,6 +79,17 @@ print_dpdk_version(void)
{
}
+int
+dpdk_get_cpu_has_isa(const char *arch, const char *feature)
+{
+ static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+ if (ovsthread_once_start(&once)) {
+ VLOG_ERR("DPDK not supported in this copy of Open vSwitch, cannot use
CPU flag based optimizations");
+ ovsthread_once_done(&once);
+ }
+ return 0;
+}
+
void
dpdk_status(const struct ovsrec_open_vswitch *cfg)
{
diff --git a/lib/dpdk.c b/lib/dpdk.c
index 37ea2973c..927dc6867 100644
--- a/lib/dpdk.c
+++ b/lib/dpdk.c
@@ -22,6 +22,7 @@
#include <sys/stat.h>
#include <getopt.h>
+#include <rte_cpuflags.h>
#include <rte_errno.h>
#include <rte_log.h>
#include <rte_memzone.h>
@@ -525,6 +526,21 @@ print_dpdk_version(void)
puts(rte_version());
}
+int
+dpdk_get_cpu_has_isa(const char *arch, const char *feature)
+{
+ /* Ensure Arch is x86_64 */
+ if (strncmp(arch, "x86_64", 6))
+ return 0;
+
+ if (strncmp(feature, "avx512f", 7) == 0)
+ return rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX512F) > 0;
+
+ VLOG_WARN("%s does not know the %s, %s combo, returning not supported.\n",
+ __func__, arch, feature);
+ return 0;
+}
+
void
dpdk_status(const struct ovsrec_open_vswitch *cfg)
{
diff --git a/lib/dpdk.h b/lib/dpdk.h
index 736a64279..6c2144624 100644
--- a/lib/dpdk.h
+++ b/lib/dpdk.h
@@ -44,4 +44,11 @@ bool dpdk_per_port_memory(void);
bool dpdk_available(void);
void print_dpdk_version(void);
void dpdk_status(const struct ovsrec_open_vswitch *);
+
+/* Returns 1 if the CPU has support for the requested architecture specific
+ * ISA capability. Eg: "x86_64", "avx512f". The strings to use here are as
+ * shown in "lscpu" Architecture: and Flags: fields.
+ */
+int dpdk_get_cpu_has_isa(const char * arch, const char *feature);
+
#endif /* dpdk.h */
diff --git a/lib/dpif-netdev-lookup-generic.c b/lib/dpif-netdev-lookup-generic.c
index 89c8be0fa..dbc830512 100644
--- a/lib/dpif-netdev-lookup-generic.c
+++ b/lib/dpif-netdev-lookup-generic.c
@@ -301,6 +301,13 @@ DECLARE_OPTIMIZED_LOOKUP_FUNCTION(4, 0)
dpcls_subtable_lookup_func
dpcls_subtable_generic_probe(uint32_t u0_bits, uint32_t u1_bits)
{
+ /* POC only: check if we can use CPU based info */
+ int avx512f_available = dpdk_get_cpu_has_isa("x86_64", "avx512f");
+ printf("avx512f available? %d\n", avx512f_available);
+
+ if (!avx512f_available)
+ return 0;
+
dpcls_subtable_lookup_func f = NULL;
CHECK_LOOKUP_FUNCTION(5, 1);
--
2.17.1
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