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Message-ID: <9c74082b-fccf-7713-b98d-50da76c5d7af@arm.com>
Date: Tue, 20 Oct 2020 22:54:44 +0100
From: André Przywara <andre.przywara@....com>
To: Leo Yan <leo.yan@...aro.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Wei Li <liwei391@...wei.com>,
James Clark <james.clark@....com>,
Dave Martin <Dave.Martin@....com>,
linux-kernel@...r.kernel.org, Al Grant <Al.Grant@....com>
Subject: Re: [PATCH v2 14/14] perf arm-spe: Add support for ARMv8.3-SPE
On 29/09/2020 14:39, Leo Yan wrote:
Hi,
> From: Wei Li <liwei391@...wei.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@...wei.com>
> Signed-off-by: Leo Yan <leo.yan@...aro.org>
> ---
> .../arm-spe-decoder/arm-spe-pkt-decoder.c | 84 ++++++++++++++++++-
> .../arm-spe-decoder/arm-spe-pkt-decoder.h | 6 ++
> 2 files changed, 87 insertions(+), 3 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 05a4c74399d7..3ec381fddfcb 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
> @@ -342,14 +342,73 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
> return ret;
> }
> }
> + if (idx > 2) {
As I mentioned in the other patch, I doubt this extra comparison is
useful. Does that protect us from anything?
> + if (payload & SPE_EVT_PKT_ALIGNMENT) {
Mmh, but this is bit 11, right? So would need to go into the (idx > 1)
section (covering bits 8-15)? Another reason to ditch this comparison above.
> + ret = snprintf(buf, buf_len, " ALIGNMENT");
> + if (ret < 0)
> + return ret;
> + buf += ret;
> + blen -= ret;
Shouldn't we use the new arm_spe_pkt_snprintf() function here as well?
Or is there a reason that this doesn't work?
> + }
> + if (payload & SPE_EVT_PKT_SVE_PARTIAL_PREDICATE) {
> + ret = snprintf(buf, buf_len, " SVE-PARTIAL-PRED");
> + if (ret < 0)
> + return ret;
> + buf += ret;
> + blen -= ret;
> + }
> + if (payload & SPE_EVT_PKT_SVE_EMPTY_PREDICATE) {
> + ret = snprintf(buf, buf_len, " SVE-EMPTY-PRED");
> + if (ret < 0)
> + return ret;
> + buf += ret;
> + blen -= ret;
> + }
> + }
> +
> return buf_len - blen;
>
> case ARM_SPE_OP_TYPE:
> switch (idx) {
> case SPE_OP_PKT_HDR_CLASS_OTHER:
> - return arm_spe_pkt_snprintf(&buf, &blen,
> - payload & SPE_OP_PKT_OTHER_SUBCLASS_COND ?
> - "COND-SELECT" : "INSN-OTHER");
> + if ((payload & SPE_OP_PKT_OTHER_SVE_SUBCLASS_MASK) ==
> + SPE_OP_PKT_OTHER_SUBCLASS_SVG_OP) {
> +
> + ret = arm_spe_pkt_snprintf(&buf, &blen, "SVE-OTHER");
> + if (ret < 0)
> + return ret;
> +
> + /* Effective vector length: step is 32 bits */
> + ret = arm_spe_pkt_snprintf(&buf, &blen, " EVLEN %d",
> + 32 << ((payload & SPE_OP_PKT_SVE_EVL_MASK) >>
> + SPE_OP_PKT_SVE_EVL_SHIFT));
Can you move this into a macro, and add a comment about how this works?
People might get confused over the "32 << something".
Cheers,
Andre
> + 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_OTHER_SUBCLASS_COND ?
> + "COND-SELECT" : "UNCOND");
> + 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_LDST ?
> @@ -394,6 +453,25 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
> ret = arm_spe_pkt_snprintf(&buf, &blen, " NV-SYSREG");
> if (ret < 0)
> return ret;
> + } else if ((payload & SPE_OP_PKT_LDST_SUBCLASS_SVE_MASK) ==
> + SPE_OP_PKT_LDST_SUBCLASS_SVE) {
> + /* Effective vector length: step is 32 bits */
> + ret = arm_spe_pkt_snprintf(&buf, &blen, " EVLEN %d",
> + 32 << ((payload & SPE_OP_PKT_SVE_EVL_MASK) >>
> + SPE_OP_PKT_SVE_EVL_SHIFT));
> + 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;
> 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 1847cad517db..80266bfebec2 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
> @@ -147,6 +147,12 @@ struct arm_spe_pkt {
> #define SPE_OP_PKT_LDST_SUBCLASS_SVE_MASK (GENMASK_ULL(3, 3) | GENMASK_ULL(1, 1))
> #define SPE_OP_PKT_LDST_SUBCLASS_SVE (0x8)
>
> +#define SPE_OP_PKT_SVE_SG BIT(7)
> +#define SPE_OP_PKT_SVE_EVL_MASK GENMASK_ULL(6, 4)
> +#define SPE_OP_PKT_SVE_EVL_SHIFT (4)
> +#define SPE_OP_PKT_SVE_PRED BIT(2)
> +#define SPE_OP_PKT_SVE_FP BIT(1)
> +
> #define SPE_OP_PKT_AR BIT(4)
> #define SPE_OP_PKT_EXCL BIT(3)
> #define SPE_OP_PKT_AT BIT(2)
>
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