From: Andi Kleen <ak@linux.intel.com>
To: Adrian Hunter <adrian.hunter@intel.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 3/6] perf intel-pt: Support itrace A option to approximate IPC
Date: Tue, 26 Oct 2021 10:03:02 -0700 [thread overview]
Message-ID: <a37ede61-c607-4fcf-2be4-12b83cdf0d7e@linux.intel.com> (raw)
In-Reply-To: <20211026090152.357591-4-adrian.hunter@intel.com>
On 10/26/2021 2:01 AM, Adrian Hunter wrote:
> Normally, for cycle-acccurate mode, IPC values are an exact number of
> instructions and cycles. Due to the granularity of timestamps, that happens
> only when a CYC packet correlates to the event.
>
> Support the itrace 'A' option, to use instead, the number of cycles
> associated with the current timestamp. This provides IPC information for
> every change of timestamp, but at the expense of accuracy.
Can you expand a bit what exactly the accuracy loss it?
Would be good to describe that in the manpage too.
next prev parent reply other threads:[~2021-10-26 17:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-26 9:01 [PATCH V2 0/6] perf dlfilter: Add dlfilter-show-cycles Adrian Hunter
2021-10-26 9:01 ` [PATCH V2 1/6] perf auxtrace: Add missing Z option to ITRACE_HELP Adrian Hunter
2021-10-26 9:01 ` [PATCH V2 2/6] perf auxtrace: Add itrace A option to approximate IPC Adrian Hunter
2021-10-26 9:01 ` [PATCH V2 3/6] perf intel-pt: Support " Adrian Hunter
2021-10-26 17:03 ` Andi Kleen [this message]
2021-10-26 9:01 ` [PATCH V2 4/6] perf dlfilter: Add dlfilter-show-cycles Adrian Hunter
2021-10-26 9:01 ` [PATCH V2 5/6] perf auxtrace: Add itrace d+o option to direct debug log to stdout Adrian Hunter
2021-10-26 9:01 ` [PATCH V2 6/6] perf intel-pt: Support " Adrian Hunter
[not found] ` <dd9f91af-8b74-bf75-b3a4-c3826be7b190@linux.intel.com>
2021-10-27 18:59 ` Arnaldo Carvalho de Melo
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=a37ede61-c607-4fcf-2be4-12b83cdf0d7e@linux.intel.com \
--to=ak@linux.intel.com \
--cc=acme@kernel.org \
--cc=adrian.hunter@intel.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.