From: "liwei (GF)" <liwei391@huawei.com>
To: Leo Yan <leo.yan@linaro.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Ian Rogers <irogers@google.com>, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Kemeng Shi <shikemeng@huawei.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Igor Lubashev <ilubashe@akamai.com>,
Andi Kleen <ak@linux.intel.com>,
Jin Yao <yao.jin@linux.intel.com>,
Stephane Eranian <eranian@google.com>,
James Clark <james.clark@arm.com>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/4] perf tools: Support Arm arch timer counter
Date: Thu, 20 Aug 2020 10:56:46 +0800 [thread overview]
Message-ID: <27ed6ebf-d9e6-e0ea-1577-2bba3d6f35c1@huawei.com> (raw)
In-Reply-To: <20200807071620.11907-2-leo.yan@linaro.org>
Hi Leo
On 2020/8/7 15:16, Leo Yan wrote:
> The Arm arch timer can be used to calculate timestamp, the basic idea is
> the arch timer's counter value can be recorded in the hardware tracing
> data, e.g. the arch timer's counter value can be used for Arm CoreSight
> (not now but might be implemented later) and Arm SPE. So we need a way
> to convert the arch timer's counter to the system time, the conversion
> is dependent on some related parameters, e.g. 'time_shift', 'time_mult',
> 'time_offset', etc; furthermore, to handle the counter wrapping issue,
> perf tool needs to know 'time_cycles' and 'time_mask' for correction.
>
> This patch is to support Arm arch timer by reading out the relevant
> parameters from the head of first mmaped page. And these parameters
> will be stored into the structure 'perf_arch_timer_conversion' for
> later calculation timestamp.
>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
> tools/perf/arch/arm64/util/Build | 1 +
> tools/perf/arch/arm64/util/arch_timer.c | 50 +++++++++++++++++++++++++
> tools/perf/util/arm_arch_timer.h | 20 ++++++++++
> 3 files changed, 71 insertions(+)
> create mode 100644 tools/perf/arch/arm64/util/arch_timer.c
> create mode 100644 tools/perf/util/arm_arch_timer.h
>
> diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
> index 5c13438c7bd4..77f4d7b30932 100644
> --- a/tools/perf/arch/arm64/util/Build
> +++ b/tools/perf/arch/arm64/util/Build
> @@ -1,3 +1,4 @@
> +perf-y += arch_timer.o
> perf-y += header.o
> perf-y += machine.o
> perf-y += perf_regs.o
> diff --git a/tools/perf/arch/arm64/util/arch_timer.c b/tools/perf/arch/arm64/util/arch_timer.c
> new file mode 100644
> index 000000000000..dcc217c294fc
> --- /dev/null
> +++ b/tools/perf/arch/arm64/util/arch_timer.c
> @@ -0,0 +1,50 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <stdbool.h>
> +#include <errno.h>
> +
> +#include <linux/stddef.h>
> +#include <linux/perf_event.h>
> +
> +#include <linux/types.h>
> +#include <asm/barrier.h>
> +#include "../../../util/debug.h"
> +#include "../../../util/event.h"
> +#include "../../../util/synthetic-events.h"
> +#include "../../../util/arm_arch_timer.h"
> +
> +int perf_read_arch_timer_conversion(const struct perf_event_mmap_page *pc,
> + struct perf_arch_timer_conversion *tc)
> +{
> + bool cap_user_time_zero, cap_user_time_short;
> + u32 seq;
> + int i = 0;
> +
> + while (1) {
> + seq = pc->lock;
> + /* Add barrier between the sequence lock and data accessing */
> + rmb();
> +
> + tc->time_mult = pc->time_mult;
> + tc->time_shift = pc->time_shift;
> + tc->time_zero = pc->time_zero;
> + tc->time_cycles = pc->time_cycles;
> + tc->time_mask = pc->time_mask;
> + cap_user_time_zero = pc->cap_user_time_zero;
> + cap_user_time_short = pc->cap_user_time_short;
> +
> + /* Add barrier between the data accessing and sequence lock */
> + rmb();
> + if (pc->lock == seq && !(seq & 1))
> + break;
> + if (++i > 10000) {
> + pr_debug("%s: failed to get perf_event_mmap_page lock\n",
> + __func__);
> + return -EINVAL;
> + }
> + }
> +
> + if (!cap_user_time_zero || !cap_user_time_short)
> + return -EOPNOTSUPP;
> +
> + return 0;
> +}
Should we implement the perf_event__synth_time_conv() method? As it can be supported
on arm64 arch now.
These is also a tsc get method called rdtsc(), weak implementation in 'tools/perf/util/tsc.c',
maybe we should rename it to an arch independent name, and implement the arm64 version
(read_cntvct_el0 in patch 3) here. Thus we can also make the testcase generic,
instead of adding a new one for arm64 :).
Thanks,
Wei
> diff --git a/tools/perf/util/arm_arch_timer.h b/tools/perf/util/arm_arch_timer.h
> new file mode 100644
> index 000000000000..a3263cc4e5cf
> --- /dev/null
> +++ b/tools/perf/util/arm_arch_timer.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __PERF_ARM_ARCH_TIMER_H
> +#define __PERF_ARM_ARCH_TIMER_H
> +
> +#include <linux/types.h>
> +
> +struct perf_arch_timer_conversion {
> + u16 time_shift;
> + u32 time_mult;
> + u64 time_zero;
> + u64 time_cycles;
> + u64 time_mask;
> +};
> +
> +struct perf_event_mmap_page;
> +
> +int perf_read_arch_timer_conversion(const struct perf_event_mmap_page *pc,
> + struct perf_arch_timer_conversion *tc);
> +
> +#endif // __PERF_ARM_ARCH_TIMER_H
>
next prev parent reply other threads:[~2020-08-20 2:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 7:16 [PATCH v2 0/4] Perf tool: Enable Arm arch timer counter and arm-spe's timestamp Leo Yan
2020-08-07 7:16 ` [PATCH v2 1/4] perf tools: Support Arm arch timer counter Leo Yan
2020-08-20 2:56 ` liwei (GF) [this message]
2020-08-21 9:36 ` Leo Yan
2020-08-07 7:16 ` [PATCH v2 2/4] perf arm_arch_timer: Convert between counter and timestamp Leo Yan
2020-08-20 3:05 ` liwei (GF)
2020-08-07 7:16 ` [PATCH v2 3/4] perf arm_arch_timer: Test conversion " Leo Yan
2020-08-07 7:16 ` [PATCH v2 4/4] perf arm-spe: Enable timestamp with arch timer counter Leo Yan
2020-08-12 16:06 ` [PATCH v2 0/4] Perf tool: Enable Arm arch timer counter and arm-spe's timestamp Mathieu Poirier
2020-08-12 18:53 ` Arnaldo Carvalho de Melo
2020-08-13 1:54 ` Leo Yan
2020-08-13 9:59 ` Will Deacon
2020-08-13 11:18 ` Will Deacon
2020-08-13 12:08 ` John Garry
2020-08-13 13:05 ` Arnaldo Carvalho de Melo
2020-08-13 16:17 ` Mathieu Poirier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=27ed6ebf-d9e6-e0ea-1577-2bba3d6f35c1@huawei.com \
--to=liwei391@huawei.com \
--cc=acme@kernel.org \
--cc=adrian.hunter@intel.com \
--cc=ak@linux.intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=eranian@google.com \
--cc=ilubashe@akamai.com \
--cc=irogers@google.com \
--cc=james.clark@arm.com \
--cc=jolsa@redhat.com \
--cc=leo.yan@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mathieu.poirier@linaro.org \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=naveen.n.rao@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=shikemeng@huawei.com \
--cc=will@kernel.org \
--cc=yao.jin@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).