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From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: dev@dpdk.org, Harry van Haaren <harry.van.haaren@intel.com>,
	Remy Horton <remy.horton@intel.com>,
	Reshma Pattan <reshma.pattan@intel.com>,
	stable@dpdk.org
Subject: Re: [PATCH] latencystats: fix missing f suffix on literal float
Date: Mon, 15 Apr 2024 16:14:05 -0700	[thread overview]
Message-ID: <20240415231405.GA31632@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> (raw)
In-Reply-To: <20240415151738.2b85fc05@hermes.local>

On Mon, Apr 15, 2024 at 03:17:38PM -0700, Stephen Hemminger wrote:
> On Mon, 15 Apr 2024 14:32:26 -0700
> Tyler Retzlaff <roretzla@linux.microsoft.com> wrote:
> 
> > Add missing f suffix to floating point literal to avoid warning about
> > truncation from double to float.
> > 
> > Fixes: 5cd3cac9ed22 ("latency: added new library for latency stats")
> > Cc: reshma.pattan@intel.com
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> > ---
> >  lib/latencystats/rte_latencystats.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/lib/latencystats/rte_latencystats.c b/lib/latencystats/rte_latencystats.c
> > index 4ea9b0d..cae4b50 100644
> > --- a/lib/latencystats/rte_latencystats.c
> > +++ b/lib/latencystats/rte_latencystats.c
> > @@ -166,7 +166,7 @@ struct latency_stats_nameoff {
> >  	 * a constant smoothing factor between 0 and 1. The value
> >  	 * is used below for measuring average latency.
> >  	 */
> > -	const float alpha = 0.2;
> > +	const float alpha = 0.2f;
> >  
> >  	now = rte_rdtsc();
> >  	for (i = 0; i < nb_pkts; i++) {
> 
> The use of floating point in fast path here is unnecessary.
> Even without doing the full per-core values, this could just change
> to an alpha of .25 and use fast fixed point math.

agree, though my thoughts are make this code correct optimization is for
the maintainer. if they submit an alternate series i can withdraw this
patch. otherwise i think we should take it as-is.

  reply	other threads:[~2024-04-15 23:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-15 21:32 Tyler Retzlaff
2024-04-15 22:17 ` Stephen Hemminger
2024-04-15 23:14   ` Tyler Retzlaff [this message]
2024-05-29 14:38     ` Thomas Monjalon

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