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Message-ID: <a8f9df67-adf1-09e7-b117-ff4163cc2a03@huawei.com>
Date: Wed, 29 Jul 2020 15:21:20 +0800
From: "liwei (GF)" <liwei391@...wei.com>
To: Leo Yan <leo.yan@...aro.org>
CC: Adrian Hunter <adrian.hunter@...el.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
James Clark <james.clark@....com>,
Jiri Olsa <jolsa@...hat.com>,
Mark Rutland <mark.rutland@....com>,
Namhyung Kim <namhyung@...nel.org>,
Suzuki K Poulose <suzuki.poulose@....com>,
Will Deacon <will@...nel.org>, <zhangshaokun@...ilicon.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...hat.com>,
"Peter Zijlstra" <peterz@...radead.org>, <guohanjun@...wei.com>
Subject: Re: [PATCH 2/4] perf: arm-spe: Add support for ARMv8.3-SPE
Hi Leo,
On 2020/7/29 14:29, Leo Yan wrote:
> On Fri, Jul 24, 2020 at 05:16:05PM +0800, Wei Li wrote:
>> Armv8.3 extends the SPE by adding:
>> - Alignment field in the Events packet, and filtering on this event
>> using PMSEVFR_EL1.
>> - Support for the Scalable Vector Extension (SVE).
>>
>> The main additions for SVE are:
>> - Recording the vector length for SVE operations in the Operation Type
>> packet. It is not possible to filter on vector length.
>> - Incomplete predicate and empty predicate fields in the Events packet,
>> and filtering on these events using PMSEVFR_EL1.
>
> This comment description is not relevant with the changes in this
> patch, so could remove them.
>
>> Add the corresponding decode process of Events packet and Operation Type
>> packet in perf tool.
>
> This patch is to add the raw dumping for Events packet and Operation Type
> packet.
>
>> Signed-off-by: Wei Li <liwei391@...wei.com>
>> ---
>> .../arm-spe-decoder/arm-spe-pkt-decoder.c | 69 ++++++++++++++++++-
>> 1 file changed, 67 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 b94001b756c7..10a3692839de 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
>> @@ -347,6 +347,24 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
>> blen -= ret;
>> }
>> }
>> + if (idx > 2) {
>> + if (payload & 0x800) {
>> + ret = snprintf(buf, buf_len, " ALIGNMENT");
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (payload & 0x20000) {
>> + ret = snprintf(buf, buf_len, " SVE-PRED-PARTIAL");
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (payload & 0x40000) {
>> + ret = snprintf(buf, buf_len, " SVE-PRED-EMPTY");
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + }
>> +
>
> Correct.
>
>> if (ret < 0)
>> return ret;
>> blen -= ret;
>> @@ -354,8 +372,38 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
>> }
>> case ARM_SPE_OP_TYPE:
>> switch (idx) {
>> - case 0: return snprintf(buf, buf_len, "%s", payload & 0x1 ?
>> - "COND-SELECT" : "INSN-OTHER");
>> + case 0: {
>> + if (payload & 0x8) {
>
> Some nitpicks for packet format checking ...
>
> For SVE operation, the payload partten is: 0b0xxx1xx0.
>
> So it's good to check the partten like:
>
> /* SVE operation subclass is: 0b0xxx1xx0 */
> if ((payload & 0x8081) == 0x80) {
> ....
> }
>
> If later the packet format is extended, this will not introduce any
> confliction.
Get it, but i think what you are really meaning is:
if ((payload & 0x89) == 0x80) {
...
}
>
>> + size_t blen = buf_len;
>> +
>> + ret = snprintf(buf, buf_len, "SVE-OTHER");
>> + buf += ret;
>> + blen -= ret;
>> + if (payload & 0x2) {
>
> Here should express as binary results: " FP" or " INT".
I think this is a style choice, i add these just like the current code where
processing "AT", "EXCL", "AR", "COND" and so on. So should we modify all the corresponding code together?
>
>> + ret = snprintf(buf, buf_len, " FP");
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (payload & 0x4) {
>> + ret = snprintf(buf, buf_len, " PRED");
>
> Here should express as binary results: " PRED" or " NOT-PRED".
Ditto.
>
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (payload & 0x70) {
>
> This is incorrect. If bits[6:4] is zero, it presents vector length is 32 bits.
>
I am a little confused here.
Refer to the ARM DDI 0487F.b (ID040120), page D10-2830, if bits[6:4] is zero,
it presents vector length is 32 bits indeed.
>> + ret = snprintf(buf, buf_len, " EVL %d",
>> + 32 << ((payload & 0x70) >> 4));
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (ret < 0)
>> + return ret;
>> + blen -= ret;
>> + return buf_len - blen;
>> + } else {
>
> Here we can check with more accurate format as defined in ARMv8 ARM:
>
> /* Other operation subclass is: 0b0000000x */
> if ((payload & 0xfe) == 0x0) {
> ....
> }
>
>> + return snprintf(buf, buf_len, "%s", payload & 0x1 ?
>> + "COND-SELECT" : "INSN-OTHER");
>> + }
>> + }
>> case 1: {
>> size_t blen = buf_len;
>>
>> @@ -385,6 +433,23 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
>> ret = snprintf(buf, buf_len, " SIMD-FP");
>> buf += ret;
>> blen -= ret;
>> + } else if (payload & 0x8) {
>> + if (payload & 0x4) {
>> + ret = snprintf(buf, buf_len, " PRED");
>
> Here should express as binary results: " PRED" or " NOT-PRED".
Ditto.
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (payload & 0x70) {
>
> This is incorrect. If bits[6:4] is zero, it presents vector length is 32 bits.
Refer to the ARM DDI 0487F.b (ID040120), page D10-2832, if bits[6:4] is zero,
it presents vector length is 32 bits indeed.
>> + ret = snprintf(buf, buf_len, " EVL %d",
>> + 32 << ((payload & 0x70) >> 4));
>> + buf += ret;
>> + blen -= ret;
>> + }
>> + if (payload & 0x80) {
>> + ret = snprintf(buf, buf_len, " SG");
>
> Here should express as binary results: " SG" or " NOT-SG".
Thanks,
Wei
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