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Message-ID: <6080472e-a117-e36d-ec4a-80f7ef93b3fb@arm.com>
Date: Tue, 20 Oct 2020 22:53:47 +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 09/14] perf arm-spe: Refactor counter packet handling
On 29/09/2020 14:39, Leo Yan wrote:
Hi,
> This patch defines macros for counter packet header, and uses macro to
> replace hard code values for packet parsing.
>
> Signed-off-by: Leo Yan <leo.yan@...aro.org>
> ---
> .../util/arm-spe-decoder/arm-spe-pkt-decoder.c | 17 ++++++++++-------
> .../util/arm-spe-decoder/arm-spe-pkt-decoder.h | 9 +++++++++
> 2 files changed, 19 insertions(+), 7 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 00a2cd1af422..ed0f4c74dfc5 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
> @@ -150,10 +150,13 @@ static int arm_spe_get_counter(const unsigned char *buf, size_t len,
> const unsigned char ext_hdr, struct arm_spe_pkt *packet)
> {
> packet->type = ARM_SPE_COUNTER;
> - if (ext_hdr)
> - packet->index = ((buf[0] & 0x3) << 3) | (buf[1] & 0x7);
> - else
> - packet->index = buf[0] & 0x7;
> + if (ext_hdr) {
> + packet->index = (buf[1] & SPE_CNT_PKT_HDR_INDEX_MASK);
> + packet->index |= ((buf[0] & SPE_CNT_PKT_HDR_EXT_INDEX_MASK)
> + << SPE_CNT_PKT_HDR_EXT_INDEX_SHIFT);
> + } else {
> + packet->index = buf[0] & SPE_CNT_PKT_HDR_INDEX_MASK;
That looks suspiciously similar to the extended header in the address
packet. Can you use the same name for that?
And, similar to the address packet, what about:
packet->index |= SPE_PKT_EXT_HEADER_INDEX(buf[0]);
(merging the mask and the shift in the macro definition)
> + }
>
> return arm_spe_get_payload(buf, len, ext_hdr, packet);
> }
> @@ -431,17 +434,17 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
> return ret;
>
> switch (idx) {
> - case 0:
> + case SPE_CNT_PKT_HDR_INDEX_TOTAL_LAT:
> ret = arm_spe_pkt_snprintf(&buf, &blen, "TOT");
> if (ret < 0)
> return ret;
> break;
> - case 1:
> + case SPE_CNT_PKT_HDR_INDEX_ISSUE_LAT:
> ret = arm_spe_pkt_snprintf(&buf, &blen, "ISSUE");
> if (ret < 0)
> return ret;
> break;
> - case 2:
> + case SPE_CNT_PKT_HDR_INDEX_TRANS_LAT:
> ret = arm_spe_pkt_snprintf(&buf, &blen, "XLAT");
> if (ret < 0)
> return ret;
> 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 62db4ff91832..18667a63f5ba 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
> @@ -89,6 +89,15 @@ struct arm_spe_pkt {
> /* Context packet header */
> #define SPE_CTX_PKT_HDR_INDEX_MASK GENMASK_ULL(1, 0)
>
> +/* Counter packet header */
> +#define SPE_CNT_PKT_HDR_INDEX_MASK GENMASK_ULL(2, 0)
> +#define SPE_CNT_PKT_HDR_INDEX_TOTAL_LAT (0x0)
> +#define SPE_CNT_PKT_HDR_INDEX_ISSUE_LAT (0x1)
> +#define SPE_CNT_PKT_HDR_INDEX_TRANS_LAT (0x2)
I think the Linux kernel coding style does not mention parentheses just
around numbers, so just 0x2 would suffice, for instance.
See section 12) in Documentation/process/coding-style.rst
Cheers,
Andre
> +
> +#define SPE_CNT_PKT_HDR_EXT_INDEX_MASK GENMASK_ULL(1, 0)
> +#define SPE_CNT_PKT_HDR_EXT_INDEX_SHIFT (3)
> +
> const char *arm_spe_pkt_name(enum arm_spe_pkt_type);
>
> int arm_spe_get_packet(const unsigned char *buf, size_t len,
>
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