From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>,
steven.sistare@oracle.com, daniel.m.jordan@oracle.com,
linux@armlinux.org.uk, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, john.stultz@linaro.org,
sboyd@codeaurora.org, x86@kernel.org,
linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com,
douly.fnst@cn.fujitsu.com, prarit@redhat.com,
feng.tang@intel.com, pmladek@suse.com,
gnomes@lxorguk.ukuu.org.uk
Subject: Re: [PATCH v10 7/7] x86/tsc: use tsc early
Date: Wed, 20 Jun 2018 11:15:32 +0200 [thread overview]
Message-ID: <20180620091532.GK2476@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.21.1806192335390.10546@nanos.tec.linutronix.de>
On Wed, Jun 20, 2018 at 01:52:10AM +0200, Thomas Gleixner wrote:
> u64 native_sched_clock(void)
> {
> + if (static_branch_likely(&__use_tsc))
> + return cycles_2_ns(rdtsc());
>
> + if (static_branch_unlikely(&tsc_early_enabled)) {
> + if (tsc_early_sched_clock)
> + return cycles_2_ns(rdtsc());
> }
I'm still puzzled by the entire need for tsc_early_enabled and all that.
Esp. since both branches do the exact same thing:
return cycles_2_ns(rdtsc());
next prev parent reply other threads:[~2018-06-20 9:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-15 17:41 [PATCH v10 0/7] Early boot time stamps for x86 Pavel Tatashin
2018-06-15 17:41 ` [PATCH v10 1/7] x86/tsc: remove tsc_disabled flag Pavel Tatashin
2018-06-19 17:32 ` Thomas Gleixner
2018-06-19 17:50 ` Pavel Tatashin
2018-06-19 18:46 ` Peter Zijlstra
2018-06-19 19:12 ` Thomas Gleixner
2018-06-19 20:01 ` Peter Zijlstra
2018-06-19 20:57 ` Thomas Gleixner
2018-06-19 21:00 ` Peter Zijlstra
2018-06-15 17:41 ` [PATCH v10 2/7] time: sync read_boot_clock64() with persistent clock Pavel Tatashin
2018-06-19 21:14 ` Thomas Gleixner
2018-06-19 21:25 ` Pavel Tatashin
2018-06-15 17:42 ` [PATCH v10 3/7] x86/time: read_boot_clock64() implementation Pavel Tatashin
2018-06-18 8:42 ` Andy Shevchenko
2018-06-18 8:44 ` Andy Shevchenko
2018-06-19 14:23 ` Pavel Tatashin
2018-06-19 20:39 ` Andy Shevchenko
2018-06-15 17:42 ` [PATCH v10 4/7] sched: early boot clock Pavel Tatashin
2018-06-15 17:42 ` [PATCH v10 5/7] kvm/x86: remove kvm memblock dependency Pavel Tatashin
2018-06-15 17:42 ` [PATCH v10 6/7] x86/paravirt: add active_sched_clock to pv_time_ops Pavel Tatashin
2018-06-19 23:13 ` Thomas Gleixner
2018-06-15 17:42 ` [PATCH v10 7/7] x86/tsc: use tsc early Pavel Tatashin
2018-06-19 22:51 ` Thomas Gleixner
2018-06-19 23:20 ` Thomas Gleixner
2018-06-19 23:52 ` Thomas Gleixner
2018-06-20 0:00 ` Pavel Tatashin
2018-06-20 9:15 ` Peter Zijlstra [this message]
2018-06-20 10:42 ` Thomas Gleixner
2018-06-20 12:32 ` Peter Zijlstra
2018-06-20 13:29 ` Thomas Gleixner
2018-06-20 21:30 ` Pavel Tatashin
2018-06-20 10:12 ` Feng Tang
2018-06-20 10:16 ` Thomas Gleixner
2018-06-20 10:29 ` Feng Tang
2018-06-20 10:30 ` Thomas Gleixner
2018-06-20 10:39 ` Feng Tang
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