Messages in this thread | | | Subject | Re: [PATCH] clocksource_cyc2ns: avoid overflowing 64 bits | From | Chris Metcalf <> | Date | Wed, 16 Nov 2016 15:30:10 -0500 |
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On 11/16/2016 3:00 PM, John Stultz wrote: > On Wed, Nov 16, 2016 at 11:56 AM, Chris Metcalf <cmetcalf@mellanox.com> wrote: >> On 11/16/2016 2:45 PM, John Stultz wrote: >>> On Wed, Nov 16, 2016 at 11:30 AM, Chris Metcalf <cmetcalf@mellanox.com> >>> wrote: >>>> diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h >>>> index 08398182f56e..5444429884b8 100644 >>>> --- a/include/linux/clocksource.h >>>> +++ b/include/linux/clocksource.h >>>> @@ -171,6 +171,10 @@ static inline u32 clocksource_hz2mult(u32 hz, u32 >>>> shift_constant) >>>> * >>>> * Converts cycles to nanoseconds, using the given mult and shift. >>>> * >>>> + * The code is optimized for performance and not intended to work >>>> + * with absolute clocksource cycles, as it will easily overflow, >>>> + * but just intended for relative (delta) clocksource cycles. >>>> + * >>>> * XXX - This could use some mult_lxl_ll() asm optimization >>> Just as a heads up, it seems your working against an older kernel, as >>> this didn't apply. Its simple enough to fix up, so I'll do so, but in >>> the future, please submit patches against something close to Linus >>> HEAD. >> >> Oops, sorry; it wasn't version skew (I'm at v4.9-rc4) but whitespace damage. >> I assumed if I just pasted the patch into Thunderbird it would work, since >> it had >> no tabs. But bizarrely, if I look at the patch in the mailer, it shows a >> two-space >> prefix, but when I save the email to a file, it has a three-space prefix. >> WTF? > Yea. Not many mailers can be trusted with sending patches. I'd > recommend git-send-email. :)
Yes, indeed. That is what I always do normally. But since I was already part way through an email written interactively in my mailer, I figured I'd be lazy and paste it in. Lesson learned...
That said, it is annoyingly difficult to pick up an in-progress email and convert it into something you can edit in, say, Emacs. You end up having to cut and paste the "To:" and "Cc:" and "Subject:" information out of your mailer's helpful GUI and into Emacs in the standard RFC822 way that git send-email understands. I'm not sure there's a better way, but at least I feel better now that I've complained about it :-)
-- Chris Metcalf, Mellanox Technologies http://www.mellanox.com
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