From: Peter Zijlstra <peterz@infradead.org>
To: Huang Rui <ray.huang@amd.com>
Cc: "Borislav Petkov" <bp@suse.de>,
"Andy Lutomirski" <luto@amacapital.net>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <lenb@kernel.org>,
"John Stultz" <john.stultz@linaro.org>,
"Frédéric Weisbecker" <fweisbec@gmail.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
"Fengguang Wu" <fengguang.wu@intel.com>,
"Aaron Lu" <aaron.lu@intel.com>,
"Suravee Suthikulanit" <suravee.suthikulpanit@amd.com>,
"Tony Li" <tony.li@amd.com>, "Ken Xue" <ken.xue@amd.com>
Subject: Re: [PATCH v5 1/2] x86, mwaitt: add monitorx and mwaitx instruction
Date: Mon, 15 Jun 2015 12:55:42 +0200 [thread overview]
Message-ID: <20150615105542.GV3644@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1434365284-1495-2-git-send-email-ray.huang@amd.com>
On Mon, Jun 15, 2015 at 06:48:03PM +0800, Huang Rui wrote:
> +/*
> + * MWAITT allows for both a timer value to get you out of the MWAIT as
> + * well as the normal exit conditions.
> + *
> + * MWAITX ECX[1]: enable timer if set
> + * MWAITX EBX[31:0]: max wait time expressed in SW P0 clocks
> + *
> + * Below is the compared data between MWAIT and MWAITX on AMD
> + * processors:
> + * MWAIT MWAITX
> + * opcode 0f 01 c9 | 0f 01 fb
> + * ECX[0] value of RFLAGS.IF seen by instruction
> + * ECX[1] unused/#GP if set | enable timer if set
> + * ECX[31:2] unused/#GP if set
> + * EAX unused (reserve for hint)
Seeing how you're stuffing a !0 value in here in the next patch, the
above comment seems slightly incorrect, no?
> + * EBX[31:0] unused | max wait time (loops)
> + *
> + * MONITOR MONITORX
> + * opcode 0f 01 c8 | 0f 01 fa
> + * EAX (logical) address to monitor
> + * ECX #GP if not zero
> + *
> + * The software P0 frequency is the same as the TSC frequency.
> + */
> +static inline void __mwaitx(unsigned long eax, unsigned long ebx,
> + unsigned long ecx)
> +{
> + /* "mwaitx %eax, %ebx, %ecx;" */
> + asm volatile(".byte 0x0f, 0x01, 0xfb;"
> + :: "a" (eax), "b" (ebx), "c" (ecx));
> +}
> +
> static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
> {
> trace_hardirqs_on();
> --
> 1.9.1
>
next prev parent reply other threads:[~2015-06-15 10:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-15 10:48 [PATCH v5 0/2] x86, mwaitt: introduce AMD mwaitt support Huang Rui
2015-06-15 10:48 ` [PATCH v5 1/2] x86, mwaitt: add monitorx and mwaitx instruction Huang Rui
2015-06-15 10:55 ` Peter Zijlstra [this message]
2015-06-15 12:42 ` Huang Rui
2015-06-15 10:48 ` [PATCH v5 2/2] x86, mwaitt: introduce mwaix delay with a configurable timer Huang Rui
2015-06-15 10:57 ` Peter Zijlstra
2015-06-15 11:15 ` Borislav Petkov
2015-06-15 14:04 ` Huang Rui
2015-06-15 14:25 ` Borislav Petkov
2015-06-15 14:33 ` Huang Rui
2015-06-15 14:14 ` Huang Rui
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