> -----Original Message-----
> From: Gavin Hu <gavin...@arm.com>
> Sent: Tuesday, July 23, 2019 9:14 PM
> To: dev@dpdk.org
> Cc: n...@arm.com; tho...@monjalon.net; step...@networkplumber.org;
> Jerin Jacob Kollanukkaran <jer...@marvell.com>; Pavan Nikhilesh
> Bhagavatula <pbhagavat...@marvell.com>;
> honnappa.nagaraha...@arm.com; gavin...@arm.com
> Subject: [EXT] [PATCH v3 1/5] eal: add the APIs to wait until equal
>
> The rte_wait_until_equalxx APIs abstract the functionality of 'polling for a
> memory location to become equal to a given value'.
>
> Signed-off-by: Gavin Hu <gavin...@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
> Reviewed-by: Steve Capper <steve.cap...@arm.com>
> Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> Acked-by: Pavan Nikhilesh <pbhagavat...@marvell.com>
> ---
> .../common/include/arch/arm/rte_atomic_64.h | 4 +
> .../common/include/arch/arm/rte_pause_64.h | 106
> +++++++++++++++++++++
> lib/librte_eal/common/include/generic/rte_pause.h | 39 +++++++-
> 3 files changed, 148 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> b/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> index 97060e4..8d742c6 100644
> --- a/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> +++ b/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> @@ -15,8 +15,12 @@ extern "C" {
>
> #include "generic/rte_atomic.h"
>
> +#ifndef dsb
> #define dsb(opt) asm volatile("dsb " #opt : : : "memory")
> +#endif
> +#ifndef dmb
> #define dmb(opt) asm volatile("dmb " #opt : : : "memory")
> +#endif
Is this change required? Please fix the root cause.
I do see some build error too.
In file included from /home/jerin/dpdk.org/build/include/rte_pause_64.h:13,
from /home/jerin/dpdk.org/build/include/rte_pause.h:13,
from
/home/jerin/dpdk.org/build/include/generic/rte_spinlock.h:25,
from /home/jerin/dpdk.org/build/include/rte_spinlock.h:17,
from /home/jerin/dpdk.org/drivers/bus/fslmc/mc/mc_sys.c:10:
/home/jerin/dpdk.org/build/include/generic/rte_pause.h: In function
'rte_wait_until_equal16':
/home/jerin/dpdk.org/build/include/generic/rte_pause.h:44:49: error: macro
"dmb" passed 1 arguments, but takes just 0
44 | __rte_wait_until_equal(addr, expected, memorder);
Command to reproduce(gcc 9.1)
rm -rf build && unset RTE_KERNELDIR && make -j T=arm64-thunderx-linux-gcc
CROSS=aarch64-linux-gnu- && sed -ri 's,(CONFIG_RTE_KNI_KMOD=)y,\1n,'
build/.config && sed -ri 's,(CONFIG_RTE_LIBRTE_VHOST_NUMA=)y,\1n,'
build/.config && sed -ri 's,(CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES=)y,\1n,'
build/.config && sed -ri 's,(CONFIG_RTE_EAL_IGB_UIO=)y,\1n,' build/.config &&
CC="ccache gcc" make -j test-build CROSS=aarch64-linux-gnu-
>
> #define rte_mb() dsb(sy)
>
> diff --git a/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> b/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> index 93895d3..1f7be0a 100644
> --- a/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> +++ b/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> @@ -17,6 +17,112 @@ static inline void rte_pause(void)
> asm volatile("yield" ::: "memory");
> }
>
> +#ifdef RTE_USE_WFE
Do we need it to be under RTE_USE_WFE? If there is no harm, no need to add
Conditional compilation to detect build errors, especially config is disabled
by default.
> +/* Wait for *addr to be updated with expected value */ static
> +__rte_always_inline void rte_wait_until_equal16(volatile uint16_t
> +*addr, uint16_t expected, int memorder) {
> + uint16_t tmp;
> + if (memorder == __ATOMIC_RELAXED)
> + asm volatile(
> + "ldxrh %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "b.eq 2f\n"
> + "sevl\n"
> + "1: wfe\n"
> + "ldxrh %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "bne 1b\n"
> + "2:\n"
> + : [tmp] "=&r" (tmp)
> + : [addr] "Q"(*addr), [expected] "r"(expected)
> + : "cc", "memory");
> + else
> + asm volatile(
> + "ldaxrh %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "b.eq 2f\n"
> + "sevl\n"
> + "1: wfe\n"
> + "ldaxrh %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "bne 1b\n"
> + "2:\n"
> + : [tmp] "=&r" (tmp)
> + : [addr] "Q"(*addr), [expected] "r"(expected)
> + : "cc", "memory");
> +}
> +
> +static __rte_always_inline void
> +rte_wait_until_equal32(volatile uint32_t *addr, uint32_t expected, int
> +memorder) {
> + uint32_t tmp;
> + if (memorder == __ATOMIC_RELAXED)
> + asm volatile(
> + "ldxr %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "b.eq 2f\n"
> + "sevl\n"
> + "1: wfe\n"
> + "ldxr %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "bne 1b\n"
> + "2:\n"
> + : [tmp] "=&r" (tmp)
> + : [addr] "Q"(*addr), [expected] "r"(expected)
> + : "cc", "memory");
> + else
> + asm volatile(
> + "ldaxr %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "b.eq 2f\n"
> + "sevl\n"
> + "1: wfe\n"
> + "ldaxr %w[tmp], %w[addr]\n"
> + "cmp %w[tmp], %w[expected]\n"
> + "bne 1b\n"
> + "2:\n"
> + : [tmp] "=&r" (tmp)
> + : [addr] "Q"(*addr), [expected] "r"(expected)
> + : "cc", "memory");
> +}
> +
> +static __rte_always_inline void
> +rte_wait_until_equal64(volatile uint64_t *addr, uint64_t expected, int
> +memorder) {
> + uint64_t tmp;
> + if (memorder == __ATOMIC_RELAXED)
> + asm volatile(
> + "ldxr %x[tmp], %x[addr]\n"
> + "cmp %x[tmp], %x[expected]\n"
> + "b.eq 2f\n"
> + "sevl\n"
> + "1: wfe\n"
> + "ldxr %x[tmp], %x[addr]\n"
> + "cmp %x[tmp], %x[expected]\n"
> + "bne 1b\n"
> + "2:\n"
> + : [tmp] "=&r" (tmp)
> + : [addr] "Q"(*addr), [expected] "r"(expected)
> + : "cc", "memory");
> + else
> + asm volatile(
> + "ldaxr %x[tmp], %x[addr]\n"
> + "cmp %x[tmp], %x[expected]\n"
> + "b.eq 2f\n"
> + "sevl\n"
> + "1: wfe\n"
> + "ldaxr %x[tmp], %x[addr]\n"
> + "cmp %x[tmp], %x[expected]\n"
> + "bne 1b\n"
> + "2:\n"
> + : [tmp] "=&r" (tmp)
> + : [addr] "Q"(*addr), [expected] "r"(expected)
> + : "cc", "memory");
Duplication of code. Please introduce a macro for assembly Skelton.
Something like
http://patches.dpdk.org/patch/56949/
> +}
> +
> +#endif
> +
> #ifdef __cplusplus
> }
> #endif
> diff --git a/lib/librte_eal/common/include/generic/rte_pause.h
> b/lib/librte_eal/common/include/generic/rte_pause.h
> index 52bd4db..8f5f025 100644
> --- a/lib/librte_eal/common/include/generic/rte_pause.h
> +++ b/lib/librte_eal/common/include/generic/rte_pause.h
> @@ -4,7 +4,6 @@
>
> #ifndef _RTE_PAUSE_H_
> #define _RTE_PAUSE_H_
> -
> /**
> * @file
> *
> @@ -12,6 +11,10 @@
> *
> */
>
> +#include <stdint.h>
> +#include <rte_common.h>
> +#include <rte_atomic.h>
> +
> /**
> * Pause CPU execution for a short while
> *
> @@ -20,4 +23,38 @@
> */
> static inline void rte_pause(void);
>
> +#if !defined(RTE_USE_WFE)
> +#ifdef RTE_USE_C11_MEM_MODEL
> +#define __rte_wait_until_equal(addr, expected, memorder) do {\
> + while (__atomic_load_n(addr, memorder) != expected) \
> + rte_pause();\
> +} while (0)
> +#else
> +#define __rte_wait_until_equal(addr, expected, memorder) do {\
> + while (*addr != expected)\
> + rte_pause();\
> + if (memorder != __ATOMIC_RELAXED)\
> + rte_smp_rmb();\
Is this correct wrt all memorder?
If there is no specific gain on no C11 mem model, let have only C11 memmodel
Aka remove RTE_USE_C11_MEM_MODEL
> +} while (0)
> +#endif
> +
Spotted public API. Lets have prototype with very good documentation on the
API details.
> +static __rte_always_inline void
> +rte_wait_until_equal16(volatile uint16_t *addr, uint16_t expected, int
> +memorder) {
> + __rte_wait_until_equal(addr, expected, memorder); }
> +
> +static __rte_always_inline void
> +rte_wait_until_equal32(volatile uint32_t *addr, uint32_t expected, int
> +memorder) {
> + __rte_wait_until_equal(addr, expected, memorder); }
> +
> +static __rte_always_inline void
> +rte_wait_until_equal64(volatile uint64_t *addr, uint64_t expected, int
> +memorder) {
> + __rte_wait_until_equal(addr, expected, memorder); } #endif /*
> +RTE_USE_WFE */
> +
> #endif /* _RTE_PAUSE_H_ */
> --
> 2.7.4
