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From: Bruce Richardson <bruce.richardson@intel.com>
To: Radu Nicolau <radu.nicolau@intel.com>
Cc: dev@dpdk.org, beilei.xing@intel.com, jia.guo@intel.com,
	konstantin.ananyev@intel.com, jerinjacobk@gmail.com
Subject: Re: [dpdk-dev] [PATCH v2 1/2] eal: add WC store functions
Date: Wed, 1 Jul 2020 14:14:38 +0100
Message-ID: <20200701131438.GC595@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <1592568380-27120-1-git-send-email-radu.nicolau@intel.com>

On Fri, Jun 19, 2020 at 01:06:19PM +0100, Radu Nicolau wrote:
> Add rte_write32_wc and rte_write32_wc_relaxed functions
> that implement 32bit stores using write combining memory protocol.
> Provided generic stubs and x86 implementation.
> 
> Signed-off-by: Radu Nicolau <radu.nicolau@intel.com>
> ---
> v2 rework new eal io functions
> 

I think you need to add into the cover letter, as suggest on V1 by
Konstantin, a bit about using WC memory for better performance.

>  lib/librte_eal/include/generic/rte_io.h | 47 ++++++++++++++++++++++++++
>  lib/librte_eal/x86/include/rte_io.h     | 59 +++++++++++++++++++++++++++++++++
>  2 files changed, 106 insertions(+)
> 
> diff --git a/lib/librte_eal/include/generic/rte_io.h b/lib/librte_eal/include/generic/rte_io.h
> index da457f7..7391782 100644
> --- a/lib/librte_eal/include/generic/rte_io.h
> +++ b/lib/librte_eal/include/generic/rte_io.h
> @@ -229,6 +229,39 @@ rte_write32(uint32_t value, volatile void *addr);
>  static inline void
>  rte_write64(uint64_t value, volatile void *addr);
>  
> +/**
> + * Write a 32-bit value to I/O device memory address addr using write
> + * combining memory write protocol. Depending on the platform write combining
> + * may not be available and/or may be treated as a hint and the behavior may
> + * fallback to a regular store.
> + *
> + * @param value
> + *  Value to write
> + * @param addr
> + *  I/O memory address to write the value to
> + */
> +static inline void
> +rte_write32_wc(uint32_t value, volatile void *addr);
> +
> +/**
> + * Write a 32-bit value to I/O device memory address addr using write
> + * combining memory write protocol. Depending on the platform write combining
> + * may not be available and/or may be treated as a hint and the behavior may
> + * fallback to a regular store.
> + *
> + * The relaxed version does not have additional I/O memory barrier, useful in
> + * accessing the device registers of integrated controllers which implicitly
> + * strongly ordered with respect to memory access.
> + *
> + * @param value
> + *  Value to write
> + * @param addr
> + *  I/O memory address to write the value to
> + */
> +static inline void
> +rte_write32_wc_relaxed(uint32_t value, volatile void *addr);
> +
> +
>  #endif /* __DOXYGEN__ */
>  
>  #ifndef RTE_OVERRIDE_IO_H
> @@ -345,6 +378,20 @@ rte_write64(uint64_t value, volatile void *addr)
>  	rte_write64_relaxed(value, addr);
>  }
>  
> +#ifndef RTE_NATIVE_WRITE32_WC
> +rte_write32_wc(uint32_t value, volatile void *addr)
> +{
> +	rte_write32(value, addr);
> +}
> +
> +static __rte_always_inline void
> +rte_write32_wc_relaxed(uint32_t value, volatile void *addr)
> +{
> +	rte_write32_relaxed(value, addr);
> +}
> +#endif /* RTE_NATIVE_WRITE32_WC */
> +
> +
>  #endif /* RTE_OVERRIDE_IO_H */
>  

I like this approach, since it saves duplicating the non-overridden
functions. Nice!

>  #endif /* _RTE_IO_H_ */
> diff --git a/lib/librte_eal/x86/include/rte_io.h b/lib/librte_eal/x86/include/rte_io.h
> index 2db71b1..5efbf0d 100644
> --- a/lib/librte_eal/x86/include/rte_io.h
> +++ b/lib/librte_eal/x86/include/rte_io.h
> @@ -9,8 +9,67 @@
>  extern "C" {
>  #endif
>  
> +#include "rte_cpuflags.h"
> +
> +#define RTE_NATIVE_WRITE32_WC
>  #include "generic/rte_io.h"
>  
> +/**
> + * @internal
> + * MOVDIRI wrapper.
> + */
> +static __rte_always_inline void
> +_rte_x86_movdiri(uint32_t value, volatile void *addr)
> +{
> +	asm volatile(
> +		/* MOVDIRI */
> +		".byte 0x40, 0x0f, 0x38, 0xf9, 0x02"
> +		:
> +		: "a" (value), "d" (addr));
> +}
> +
> +static __rte_always_inline void
> +rte_write32_wc(uint32_t value, volatile void *addr)
> +{
> +	static int _x86_movdiri_flag = -1;
> +	if (_x86_movdiri_flag == 1) {
> +		rte_wmb();
> +		_rte_x86_movdiri(value, addr);
> +	} else if (_x86_movdiri_flag == 0) {
> +		rte_write32(value, addr);
> +	} else {
> +		_x86_movdiri_flag =
> +			(rte_cpu_get_flag_enabled(RTE_CPUFLAG_MOVDIRI) > 0);
> +		if (_x86_movdiri_flag == 1) {
> +			rte_wmb();
> +			_rte_x86_movdiri(value, addr);
> +		} else {
> +			rte_write32(value, addr);
> +		}
> +	}
> +}
> +
> +static __rte_always_inline void
> +rte_write32_wc_relaxed(uint32_t value, volatile void *addr)
> +{
> +	static int _x86_movdiri_flag = -1;
> +	if (_x86_movdiri_flag == 1) {
> +		_rte_x86_movdiri(value, addr);
> +	} else if (_x86_movdiri_flag == 0) {
> +		rte_write32_relaxed(value, addr);
> +	} else {
> +		_x86_movdiri_flag =
> +			(rte_cpu_get_flag_enabled(RTE_CPUFLAG_MOVDIRI) > 0);
> +		if (_x86_movdiri_flag == 1)
> +			_rte_x86_movdiri(value, addr);
> +		else
> +			rte_write32_relaxed(value, addr);
> +	}
> +}
> +
> +
> +
> +

Rather a lot of whitespace here.

>  #ifdef __cplusplus
>  }
>  #endif
> -- 
> 2.7.4

With the nits called out above fixed:

Acked-by: Bruce Richardson <bruce.richarson@intel.com>

  parent reply	other threads:[~2020-07-01 13:14 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-11 10:11 [dpdk-dev] [PATCH v1 1/2] eal/x86: add WC store function Radu Nicolau
2020-06-11 10:11 ` [dpdk-dev] [PATCH v1 2/2] net/i40e: use movdiri to update queue tail registers Radu Nicolau
2020-06-11 12:23 ` [dpdk-dev] [PATCH v1 1/2] eal/x86: add WC store function Jerin Jacob
2020-06-11 13:56   ` Nicolau, Radu
2020-06-11 15:33     ` Jerin Jacob
2020-06-15 11:11 ` Ananyev, Konstantin
2020-06-19 12:06 ` [dpdk-dev] [PATCH v2 1/2] eal: add WC store functions Radu Nicolau
2020-06-19 12:06   ` [dpdk-dev] [PATCH v2 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-01 13:15     ` Bruce Richardson
2020-07-01 13:14   ` Bruce Richardson [this message]
2020-07-01 14:15 ` [dpdk-dev] [PATCH v3 0/2] eal: add WC store functions Radu Nicolau
2020-07-01 14:15   ` [dpdk-dev] [PATCH v3 1/2] " Radu Nicolau
2020-07-01 14:15   ` [dpdk-dev] [PATCH v3 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-02  9:23 ` [dpdk-dev] [PATCH v4 0/2] eal: add WC store functions Radu Nicolau
2020-07-02  9:23   ` [dpdk-dev] [PATCH v4 1/2] " Radu Nicolau
2020-07-03 15:19     ` David Marchand
2020-07-06  9:15       ` Nicolau, Radu
2020-07-02  9:23   ` [dpdk-dev] [PATCH v4 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-06 12:29 ` [dpdk-dev] [PATCH v5 0/2] eal: add WC store functions Radu Nicolau
2020-07-06 12:29   ` [dpdk-dev] [PATCH v5 1/2] " Radu Nicolau
2020-07-06 12:30   ` [dpdk-dev] [PATCH v5 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-13 12:27 ` [dpdk-dev] [PATCH v6 0/4] eal: add WC store functions Radu Nicolau
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 1/4] " Radu Nicolau
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 3/4] qat: " Radu Nicolau
2020-07-13 12:44     ` Bruce Richardson
2020-07-13 12:52       ` Trahe, Fiona
2020-07-13 12:57         ` Bruce Richardson
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 4/4] net/ixgbe: use WC store to update doorbell register Radu Nicolau
2020-07-16 12:29 ` [dpdk-dev] [PATCH v7 0/4] eal: add WC store functions Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 1/4] " Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 3/4] common/qat: " Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 4/4] net/ixgbe: use WC store to update doorbell register Radu Nicolau
2020-07-17 10:49 ` [dpdk-dev] [PATCH v8 0/4] eal: add WC store functions Radu Nicolau
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 1/4] " Radu Nicolau
2020-07-20  6:42     ` Ruifeng Wang
2020-07-20  8:52       ` Nicolau, Radu
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-20  6:46     ` Ruifeng Wang
2020-07-20  8:54       ` Nicolau, Radu
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 3/4] common/qat: " Radu Nicolau
2020-07-17 16:42     ` Trahe, Fiona
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 4/4] net/ixgbe: " Radu Nicolau
2020-07-17 11:18     ` Ananyev, Konstantin
2020-07-20  9:12 ` [dpdk-dev] [PATCH v9 0/4] eal: add WC store functions Radu Nicolau
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 1/4] " Radu Nicolau
2020-07-20 12:20     ` David Marchand
2020-07-21  8:56       ` Nicolau, Radu
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 3/4] common/qat: " Radu Nicolau
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 4/4] net/ixgbe: " Radu Nicolau
2020-07-21 11:31 ` [dpdk-dev] [PATCH v10 0/4] eal: add WC store functions Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 1/4] " Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 3/4] common/qat: " Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 4/4] net/ixgbe: " Radu Nicolau
2020-08-26  9:55 ` [dpdk-dev] [PATCH v11 0/5] eal: add WC store functions Radu Nicolau
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 1/5] " Radu Nicolau
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 2/5] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-09-23  1:19     ` Lu, Wenzhuo
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 3/5] common/qat: " Radu Nicolau
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 4/5] net/ixgbe: " Radu Nicolau
2020-09-23  1:20     ` Lu, Wenzhuo
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 5/5] net/ice: " Radu Nicolau
2020-09-23  1:20     ` Lu, Wenzhuo
2020-09-23 14:22 ` [dpdk-dev] [PATCH v12 0/5] eal: add WC store functions Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 1/5] " Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 2/5] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 3/5] common/qat: " Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 4/5] net/ixgbe: " Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 5/5] net/ice: " Radu Nicolau
2020-10-08  7:28   ` [dpdk-dev] [PATCH v12 0/5] eal: add WC store functions David Marchand
2020-10-08  9:51     ` Nicolau, Radu
2020-10-13  8:57     ` Ferruh Yigit
2020-10-13 12:50   ` David Marchand

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