Re: [PATCH v3 20/20] perf arm-spe: Add support for ARMv8.3-SPE

["André Przywara" <andre.przywara@arm.com>]

On 22/10/2020 15:58, Leo Yan wrote:

Hi,

> From: Wei Li <liwei391@huawei.com>
> 
> This patch is to support Armv8.3 extension for SPE, it adds alignment
> field in the Events packet and it supports the Scalable Vector Extension
> (SVE) for Operation packet and Events packet with two additions:
> 
>   - The vector length for SVE operations in the Operation Type packet;
>   - The incomplete predicate and empty predicate fields in the Events
>     packet.
> 
> Signed-off-by: Wei Li <liwei391@huawei.com>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
>  .../arm-spe-decoder/arm-spe-pkt-decoder.c     | 74 ++++++++++++++++++-
>  .../arm-spe-decoder/arm-spe-pkt-decoder.h     | 18 +++++
>  2 files changed, 90 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> index 74ac12cbec69..6da4cfbc9914 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> @@ -332,6 +332,21 @@ static int arm_spe_pkt_desc_event(const struct arm_spe_pkt *packet,
>  		if (ret < 0)
>  			return ret;
>  	}
> +	if (payload & BIT(EV_ALIGNMENT)) {
> +		ret = arm_spe_pkt_snprintf(&buf, &blen, " ALIGNMENT");
> +		if (ret < 0)
> +			return ret;
> +	}
> +	if (payload & BIT(EV_PARTIAL_PREDICATE)) {
> +		ret = arm_spe_pkt_snprintf(&buf, &blen, " SVE-PARTIAL-PRED");
> +		if (ret < 0)
> +			return ret;
> +	}
> +	if (payload & BIT(EV_EMPTY_PREDICATE)) {
> +		ret = arm_spe_pkt_snprintf(&buf, &blen, " SVE-EMPTY-PRED");
> +		if (ret < 0)
> +			return ret;
> +	}
>  
>  	return buf_len - blen;
>  }
> @@ -345,8 +360,43 @@ static int arm_spe_pkt_desc_op_type(const struct arm_spe_pkt *packet,
>  
>  	switch (class) {
>  	case SPE_OP_PKT_HDR_CLASS_OTHER:
> -		return arm_spe_pkt_snprintf(&buf, &blen,
> -			payload & SPE_OP_PKT_COND ? "COND-SELECT" : "INSN-OTHER");
> +		if (SPE_OP_PKT_OTHER_SUBCLASS_SVE_OP_GET(payload) ==
> +				SPE_OP_PKT_OTHER_SUBCLASS_SVE_OP) {

Same comment as in the other patch, can you combine those two into one
symbol?

> +
> +			ret = arm_spe_pkt_snprintf(&buf, &blen, "SVE-OTHER");
> +			if (ret < 0)
> +				return ret;
> +
> +			/* SVE effective vector length */
> +			ret = arm_spe_pkt_snprintf(&buf, &blen, " EVLEN %d",
> +						   SPE_OP_PKG_SVE_EVL(payload));
> +			if (ret < 0)
> +				return ret;
> +
> +			if (payload & SPE_OP_PKT_SVE_FP) {
> +				ret = arm_spe_pkt_snprintf(&buf, &blen, " FP");
> +				if (ret < 0)
> +					return ret;
> +			}
> +			if (payload & SPE_OP_PKT_SVE_PRED) {
> +				ret = arm_spe_pkt_snprintf(&buf, &blen, " PRED");
> +				if (ret < 0)
> +					return ret;
> +			}
> +		} else {
> +			ret = arm_spe_pkt_snprintf(&buf, &blen, "OTHER");
> +			if (ret < 0)
> +				return ret;
> +
> +			ret = arm_spe_pkt_snprintf(&buf, &blen, " %s",
> +					payload & SPE_OP_PKT_COND ?
> +					"COND-SELECT" : "INSN-OTHER");
> +			if (ret < 0)
> +				return ret;
> +		}
> +
> +		return buf_len - blen;
> +
>  	case SPE_OP_PKT_HDR_CLASS_LD_ST_ATOMIC:
>  		ret = arm_spe_pkt_snprintf(&buf, &blen,
>  					   payload & SPE_OP_PKT_ST ? "ST" : "LD");
> @@ -401,6 +451,26 @@ static int arm_spe_pkt_desc_op_type(const struct arm_spe_pkt *packet,
>  			break;
>  		}
>  
> +		if (SPE_OP_PKT_LDST_SUBCLASS_SVE_GET(payload) ==
> +				SPE_OP_PKT_LDST_SUBCLASS_SVE) {

Same here, could be combined into one symbol.

> +			/* SVE effective vector length */
> +			ret = arm_spe_pkt_snprintf(&buf, &blen, " EVLEN %d",
> +						   SPE_OP_PKG_SVE_EVL(payload));
> +			if (ret < 0)
> +				return ret;
> +
> +			if (payload & SPE_OP_PKT_SVE_PRED) {
> +				ret = arm_spe_pkt_snprintf(&buf, &blen, " PRED");
> +				if (ret < 0)
> +					return ret;
> +			}
> +			if (payload & SPE_OP_PKT_SVE_SG) {
> +				ret = arm_spe_pkt_snprintf(&buf, &blen, " SG");
> +				if (ret < 0)
> +					return ret;
> +			}
> +		}
> +
>  		return buf_len - blen;
>  
>  	case SPE_OP_PKT_HDR_CLASS_BR_ERET:
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
> index d69af0d618ea..04bc09f3ea17 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
> @@ -118,6 +118,9 @@ enum arm_spe_events {
>  #define SPE_OP_PKT_HDR_CLASS_LD_ST_ATOMIC	0x1
>  #define SPE_OP_PKT_HDR_CLASS_BR_ERET		0x2
>  
> +#define SPE_OP_PKT_OTHER_SUBCLASS_SVE_OP_GET(v)	((v) & (BIT(7) | BIT(3) | BIT(0)))
> +#define SPE_OP_PKT_OTHER_SUBCLASS_SVE_OP	0x8
> +
>  #define SPE_OP_PKT_COND				BIT(0)
>  
>  #define SPE_OP_PKT_LDST_SUBCLASS_GET(v)		((v) & GENMASK_ULL(7, 1))
> @@ -134,6 +137,21 @@ enum arm_spe_events {
>  #define SPE_OP_PKT_AT				BIT(2)
>  #define SPE_OP_PKT_ST				BIT(0)
>  
> +#define SPE_OP_PKT_LDST_SUBCLASS_SVE_GET(v)	((v) & (GENMASK_ULL(3, 3) | GENMASK_ULL(1, 1)))
> +#define SPE_OP_PKT_LDST_SUBCLASS_SVE		0x8
> +
> +#define SPE_OP_PKT_SVE_SG			BIT(7)
> +/*
> + * SVE effective vector length (EVL) is stored in byte 0 bits [6:4];
> + * the length is rounded up to a power of two and use 32 as one step,
> + * so EVL calculation is:
> + *
> + *   32 * (2 ^ bits [6:4]) = 32 << (bits [6:4])
> + */

Thanks for adding the comment!

Cheers,
Andre

> +#define SPE_OP_PKG_SVE_EVL(v)			(32 << (((v) & GENMASK_ULL(6, 4)) >> 4))
> +#define SPE_OP_PKT_SVE_PRED			BIT(2)
> +#define SPE_OP_PKT_SVE_FP			BIT(1)
> +
>  #define SPE_OP_PKT_BRANCH_SUBCLASS_GET(v)	((v) & GENMASK_ULL(7, 1))
>  #define SPE_OP_PKT_BRANCH_SUBCLASS_DIRECT	0x0
>  #define SPE_OP_PKT_BRANCH_SUBCLASS_INDIRECT	0x2
>