From: John Kacur <jkacur@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>,
Chuck Newman <chuck.newman@hpe.com>
Subject: Re: [PATCH] rt-tests: oslat: convert to nanoseconds correctly
Date: Fri, 2 Feb 2024 11:34:11 -0500 (EST) [thread overview]
Message-ID: <0a607b79-846b-f55b-a891-d00c3e630baf@redhat.com> (raw)
In-Reply-To: <ZbvZ/l9zKjU8Frvy@tpad>
On Thu, 1 Feb 2024, Marcelo Tosatti wrote:
>
> With buckets of size 1us, accounting for measurements in the
> [1ns, 999ns] range are done to the 2us bucket (while they
> should be accounted in the 1us bucket):
>
> 001 (us): 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> 002 (us): 41916187 41937649 41938461 42029055 ...
> 003 (us): 969 985 958 972 964 986 970 961 973 ...
>
> Fix this by doing a plain cycles -> nanoseconds convertion:
>
> 001 (us): 43287555 43086678 43087427 43109974 ...
> 002 (us): 983 987 985 975 982 960 993 961 992 ...
> 003 (us): 9 6 7 13 9 22 3 21 3 3 8 8 10 11 3 55
>
>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> Reported-by: Chuck Newman <chuck.newman@hpe.com>
>
> diff --git a/src/oslat/oslat.c b/src/oslat/oslat.c
> index 4bdca64..13e887d 100644
> --- a/src/oslat/oslat.c
> +++ b/src/oslat/oslat.c
> @@ -334,7 +334,7 @@ static void insert_bucket(struct thread *t, stamp_t value)
> uint64_t extra;
> double us;
>
> - lat = (value * g.unit_per_us + t->counter_mhz - 1) / t->counter_mhz;
> + lat = (value * g.unit_per_us) / t->counter_mhz;
> us = (double)lat / g.unit_per_us;
> if (!g.preheat && g.trace_threshold && us >= g.trace_threshold) {
> char *line = "%s: Trace threshold (%d us) triggered on cpu %d with %.*f us!\n";
>
>
>
Signed-off-by: John Kacur <jkacur@redhat.com>
prev parent reply other threads:[~2024-02-02 16:34 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-01 17:50 [PATCH] rt-tests: oslat: convert to nanoseconds correctly Marcelo Tosatti
2024-02-02 16:34 ` John Kacur [this message]
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=0a607b79-846b-f55b-a891-d00c3e630baf@redhat.com \
--to=jkacur@redhat.com \
--cc=chuck.newman@hpe.com \
--cc=linux-rt-users@vger.kernel.org \
--cc=mtosatti@redhat.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 read-only IMAP folder(s) and NNTP newsgroup(s).