All of lore.kernel.org
 help / color / mirror / Atom feed
From: Stephen Hemminger <stephen@networkplumber.org>
To: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
Cc: "Jacob,  Jerin" <Jerin.JacobKollanukkaran@cavium.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Bhagavatula, Pavan" <Pavan.Bhagavatula@cavium.com>
Subject: Re: [PATCH] eal: roundup tsc frequency when estimating it
Date: Thu, 29 Nov 2018 13:21:52 -0800	[thread overview]
Message-ID: <20181129132152.754ce410@xeon-e3> (raw)
In-Reply-To: <20181129083138.23029-1-pbhagavatula@caviumnetworks.com>

On Thu, 29 Nov 2018 08:32:03 +0000
Pavan Nikhilesh <pbhagavatula@caviumnetworks.com> wrote:

> When estimating tsc frequency using sleep/gettime round it up to the
> nearest multiple of 10Mhz for more accuracy.
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>

Rounding reduces accuracy.

Why is this code being used?  Shouldn't get_tsc_freq_arch return a
correct value?

How well does the rdmsr() logic work in VM?
It looks like Hyper-V has special MSR's for TSC frequency determination.

  parent reply	other threads:[~2018-11-29 21:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-29  8:32 [PATCH] eal: roundup tsc frequency when estimating it Pavan Nikhilesh
2018-11-29  9:08 ` Jerin Jacob
2018-11-29 21:21 ` Stephen Hemminger [this message]
2018-11-30  7:17   ` Pavan Nikhilesh
2019-03-16  7:03 ` [PATCH v2 1/2] eal: add macro to align value to the nearest multiple Pavan Nikhilesh Bhagavatula
2019-03-16  7:03   ` [PATCH v2 2/2] eal: roundup tsc frequency when estimating it Pavan Nikhilesh Bhagavatula
2019-03-16 14:42     ` Wiles, Keith
2019-03-16 15:06       ` [EXT] " Pavan Nikhilesh Bhagavatula
2019-03-16 17:18         ` Wiles, Keith
2019-03-16 17:56           ` Pavan Nikhilesh Bhagavatula
2019-03-16 18:22             ` Wiles, Keith
2019-03-16 18:27               ` Pavan Nikhilesh Bhagavatula
2019-03-16 19:01 ` [PATCH v3 1/2] eal: add macro to align value to the nearest multiple Pavan Nikhilesh Bhagavatula
2019-03-16 19:01   ` [PATCH v3 2/2] eal: roundup tsc frequency when estimating Pavan Nikhilesh Bhagavatula
2019-03-27 22:43     ` Thomas Monjalon

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=20181129132152.754ce410@xeon-e3 \
    --to=stephen@networkplumber.org \
    --cc=Jerin.JacobKollanukkaran@cavium.com \
    --cc=Pavan.Bhagavatula@cavium.com \
    --cc=dev@dpdk.org \
    --cc=pbhagavatula@caviumnetworks.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 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.