From: Thomas Gleixner <tglx@linutronix.de>
To: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>, x86-ml <x86@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Steven Rostedt <rostedt@goodmis.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -v2] x86: Kill notsc
Date: Wed, 4 Nov 2015 11:21:45 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.11.1511041120120.4032@nanos> (raw)
In-Reply-To: <20151022185122.GC3442@pd.tnic>
On Thu, 22 Oct 2015, Borislav Petkov wrote:
> u64 native_sched_clock(void)
> {
> - if (static_branch_likely(&__use_tsc)) {
> - u64 tsc_now = rdtsc();
> -
> - /* return the value in ns */
> - return cycles_2_ns(tsc_now);
> - }
> -
> +#ifdef CONFIG_X86_TSC
> + /* return the value in ns */
> + return cycles_2_ns(rdtsc());
> +#else
> /*
> - * Fall back to jiffies if there's no TSC available:
> - * ( But note that we still use it if the TSC is marked
> - * unstable. We do this because unlike Time Of Day,
> - * the scheduler clock tolerates small errors and it's
> - * very important for it to be as fast as the platform
> - * can achieve it. )
> + * Fall back to jiffies if there's no TSC available: ( But note that we
> + * still use it if the TSC is marked unstable. We do this because unlike
> + * Time Of Day, the scheduler clock tolerates small errors and it's very
> + * important for it to be as fast as the platform can achieve it. )
This comment does not make any sense with this modification.
Thanks,
tglx
next prev parent reply other threads:[~2015-11-04 10:22 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-18 14:20 [RFC PATCH] x86: Kill notsc Borislav Petkov
2015-10-19 4:47 ` Andy Lutomirski
2015-10-19 8:16 ` Borislav Petkov
2015-10-21 17:58 ` Borislav Petkov
2015-10-21 19:01 ` Peter Zijlstra
2015-10-22 18:51 ` [PATCH -v2] " Borislav Petkov
2015-11-04 10:21 ` Thomas Gleixner [this message]
2015-11-04 10:29 ` Borislav Petkov
2015-11-16 18:45 ` [RFC PATCH -v2.1] " Borislav Petkov
2015-11-16 21:25 ` Thomas Gleixner
2015-11-17 5:02 ` H. Peter Anvin
2015-11-17 8:53 ` Borislav Petkov
2015-11-17 9:11 ` Thomas Gleixner
2015-11-17 9:33 ` Borislav Petkov
2015-11-17 10:08 ` Thomas Gleixner
2015-11-17 11:09 ` Borislav Petkov
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