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dpif-netdev: Call cpuid for x86 isa availability.

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DPIF AVX512 optimizations currently rely on DPDK availability while
they can be used without DPDK.
Besides, checking for availability of some isa only has to be done once
and won't change while a OVS process runs.

Resolve isa availability in constructors by using a simplified query
based on cpuid API that comes from the compiler.

Note: this also fixes the check on BMI2 availability: DPDK had a bug
for this isa, see https://git.dpdk.org/dpdk/commit/?id=aae3037ab1e0.

Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
This commit is contained in:
David Marchand
2021-12-15 17:35:33 +01:00
committed by Ilya Maximets
parent 11441385c2
commit b366fa2f49
9 changed files with 119 additions and 74 deletions
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52
lib/dpdk.c
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@@ -592,58 +592,6 @@ print_dpdk_version(void)
puts(rte_version());
}
/* Avoid calling rte_cpu_get_flag_enabled() excessively, by caching the
* result of the call for each CPU flag in a static variable. To avoid
* allocating large numbers of static variables, use a uint8 as a bitfield.
* Note the macro must only return if the ISA check is done and available.
*/
#define ISA_CHECK_DONE_BIT (1 << 0)
#define ISA_AVAILABLE_BIT (1 << 1)
#define CHECK_CPU_FEATURE(feature, name_str, RTE_CPUFLAG) \
do { \
if (strncmp(feature, name_str, strlen(name_str)) == 0) { \
static uint8_t isa_check_##RTE_CPUFLAG; \
int check = isa_check_##RTE_CPUFLAG & ISA_CHECK_DONE_BIT; \
if (OVS_UNLIKELY(!check)) { \
int has_isa = rte_cpu_get_flag_enabled(RTE_CPUFLAG); \
VLOG_DBG("CPU flag %s, available %s\n", \
name_str, has_isa ? "yes" : "no"); \
isa_check_##RTE_CPUFLAG = ISA_CHECK_DONE_BIT; \
if (has_isa) { \
isa_check_##RTE_CPUFLAG |= ISA_AVAILABLE_BIT; \
} \
} \
if (isa_check_##RTE_CPUFLAG & ISA_AVAILABLE_BIT) { \
return true; \
} else { \
return false; \
} \
} \
} while (0)
bool
dpdk_get_cpu_has_isa(const char *arch, const char *feature)
{
/* Ensure Arch is x86_64. */
if (strncmp(arch, "x86_64", 6) != 0) {
return false;
}
#if __x86_64__
/* CPU flags only defined for the architecture that support it. */
CHECK_CPU_FEATURE(feature, "avx512f", RTE_CPUFLAG_AVX512F);
CHECK_CPU_FEATURE(feature, "avx512bw", RTE_CPUFLAG_AVX512BW);
CHECK_CPU_FEATURE(feature, "avx512vbmi", RTE_CPUFLAG_AVX512VBMI);
CHECK_CPU_FEATURE(feature, "avx512vpopcntdq", RTE_CPUFLAG_AVX512VPOPCNTDQ);
CHECK_CPU_FEATURE(feature, "bmi2", RTE_CPUFLAG_BMI2);
#endif
VLOG_WARN("Unknown CPU arch,feature: %s,%s. Returning not supported.\n",
arch, feature);
return false;
}
void
dpdk_status(const struct ovsrec_open_vswitch *cfg)
{