Messages in this thread | | | From | Vladimir Oltean <> | Subject | Re: [PATCH net-next 1/4] time64.h: define PSEC_PER_NSEC and use it in tc-taprio | Date | Mon, 27 Jun 2022 10:06:15 +0000 |
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On Mon, Jun 27, 2022 at 10:25:42AM +0100, Vincenzo Frascino wrote: > Hi Vladimir, > > On 6/27/22 09:51, Vladimir Oltean wrote: > > Hi Vincenzo, > > > > On Mon, Jun 27, 2022 at 08:52:51AM +0100, Vincenzo Frascino wrote: > >> Hi Vladimir, > >> > >> On 6/26/22 13:05, Vladimir Oltean wrote: > >>> Time-sensitive networking code needs to work with PTP times expressed in > >>> nanoseconds, and with packet transmission times expressed in > >>> picoseconds, since those would be fractional at higher than gigabit > >>> speed when expressed in nanoseconds. > >>> > >>> Convert the existing uses in tc-taprio to a PSEC_PER_NSEC macro. > >>> > >>> Cc: Andy Lutomirski <luto@kernel.org> > >>> Cc: Thomas Gleixner <tglx@linutronix.de> > >>> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> > >>> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> > >>> --- > >>> include/vdso/time64.h | 1 + > >>> net/sched/sch_taprio.c | 4 ++-- > >>> 2 files changed, 3 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/include/vdso/time64.h b/include/vdso/time64.h > >>> index b40cfa2aa33c..f1c2d02474ae 100644 > >>> --- a/include/vdso/time64.h > >>> +++ b/include/vdso/time64.h > >>> @@ -6,6 +6,7 @@ > >>> #define MSEC_PER_SEC 1000L > >>> #define USEC_PER_MSEC 1000L > >>> #define NSEC_PER_USEC 1000L > >>> +#define PSEC_PER_NSEC 1000L > >> > >> Are you planning to use this definition in the vdso library code? If not, you > >> should define PSEC_PER_NSEC in "include/linux/time64.h". The vdso namespace > >> should contain only the definitions shared by the implementations of the kernel > >> and of the vdso library. > > > > I am not. I thought it would be ok to preserve the locality of > > definitions by placing this near the others of its kind, since a macro > > doesn't affect the compiled vDSO code in any way. But if you prefer, I > > can create a new mini-section in linux/time64.h. Any preference on where > > exactly to place that definition within the file? > > I do not have a strong opinion on where to put it. But I think that if you put a > section above TIME64_MAX should work.
@networking people: do you mind if in v2 I move this patch to the end, hardcode 1000 in the current DSA patch 4/4, and then replace it afterwards with PSEC_PER_NSEC, together with tc-taprio? I'd like to leave the code in a clean state, but remember this is also a patch that fixes a functional issue, even if on net-next, so one dependency less can't hurt, for those who'll want to backport.
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