From: Ralf Baechle <ralf@linux-mips.org>
To: Markos Chandras <Markos.Chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Subject: Re: [PATCH 02/19] MIPS: Add cases for CPU_I6400
Date: Thu, 9 Jul 2015 13:43:58 +0200 [thread overview]
Message-ID: <20150709114358.GC31002@linux-mips.org> (raw)
In-Reply-To: <559E499E.1040504@imgtec.com>
On Thu, Jul 09, 2015 at 11:14:54AM +0100, Markos Chandras wrote:
> On 07/09/2015 11:03 AM, Ralf Baechle wrote:
> > On Thu, Jul 09, 2015 at 10:40:36AM +0100, Markos Chandras wrote:
> >
> >> index d41e8e284825..abee2bfd10dc 100644
> >> --- a/arch/mips/include/asm/cpu-type.h
> >> +++ b/arch/mips/include/asm/cpu-type.h
> >> @@ -77,6 +77,10 @@ static inline int __pure __get_cpu_type(const int cpu_type)
> >> */
> >> #endif
> >>
> >> +#ifdef CONFIG_SYS_HAS_CPU_MIPS64_R6
> >> + case CPU_I6400:
> >> +#endif
> >> +
> >
> > To ensure best possible optimization you may want to introduce a new
> > CPU type CPU_I6400 in Kconfig then change above code segment to
> >
> > #ifdef CONFIG_SYS_HAS_CPU_I6400
> > case CPU_I6400:
> > #endif
> >
>
> Why? That function uses MIPS32_XX and MIPS64_XX in other places as well.
This is one matters a lot for optimization by GCC.
Currently you're ok for as long as The I6400 stays the sole CPU wrapped
by #ifdef CONFIG_SYS_HAS_CPU_MIPS64_R6. As soon as another CPU becomes
does the same optimization will suffer.
Example:
#ifdef CONFIG_SYS_HAS_CPU_MIPS32_R1
case CPU_4KC:
case CPU_ALCHEMY:
case CPU_PR4450:
#endif
GCC is clever enough these days to figure out that __get_cpu_type() will
only return certain values so it will do some optimization but the best
case of course is if __get_cpu_type() returns one value only.
Ralf
next prev parent reply other threads:[~2015-07-09 11:44 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 9:40 [PATCH 00/19] Initial I6400 and CM3 support Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 01/19] MIPS: Add MIPS I6400 PRid and cputype identifiers Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 02/19] MIPS: Add cases for CPU_I6400 Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 10:03 ` Ralf Baechle
2015-07-09 10:14 ` Markos Chandras
2015-07-09 10:14 ` Markos Chandras
2015-07-09 11:43 ` Ralf Baechle [this message]
2015-07-09 9:40 ` [PATCH 03/19] MIPS: Add MIPS I6400 probe support Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 04/19] MIPS: Kconfig: Disable MIPS MT and SMP implementations for R6 Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 05/19] MIPS: asm: mips-cm: Implement mips_cm_revision Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 11:09 ` Sergei Shtylyov
2015-07-09 16:05 ` Markos Chandras
2015-07-09 16:05 ` Markos Chandras
2015-07-09 11:29 ` James Hogan
2015-07-09 11:29 ` James Hogan
2015-07-09 16:05 ` Markos Chandras
2015-07-09 16:05 ` Markos Chandras
2015-07-10 9:12 ` [PATCH v2 " Markos Chandras
2015-07-10 9:12 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 06/19] MIPS: asm: add CM GCR_L2_CONFIG register accessors Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 07/19] MIPS: mm: c-r4k: extend way_string array Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 08/19] MIPS: support CM3 L2 cache Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 09/19] MIPS: Add platform callback before initializing the " Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 10/19] MIPS: asm: mips-cm: Extend CM accessors for 64-bit CPUs Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-14 8:14 ` [PATCH v2 " Markos Chandras
2015-07-14 8:14 ` Markos Chandras
2015-07-14 8:30 ` Paul Burton
2015-07-14 8:30 ` Paul Burton
2015-07-14 8:35 ` Paul Burton
2015-07-14 8:35 ` Paul Burton
2015-07-14 8:45 ` Markos Chandras
2015-07-14 8:45 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 11/19] MIPS: kernel: mips-cm: The CMGCRBase register is 64-bit on MIPS64 Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 12/19] MIPS: kernel: mips-cpc: Fix type for GCR CPC base reg for 64-bit Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 13/19] MIPS: kernel: mips-cm: Add support for reporting CM cache errors Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 14/19] drivers: irqchip: irq-mips-gic: Extend GIC accessors for 64-bit CMs Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-14 9:26 ` [PATCH v2 " Markos Chandras
2015-07-14 9:26 ` Markos Chandras
2015-07-14 11:57 ` Jonas Gorski
2015-07-14 12:21 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 15/19] drivers: irqchip: irq-mips-gic: Add support for CM3 64-bit timer irqs Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 16/19] MIPS: kernel: cpu-probe: Remove cp0 hazard barrier when enabling the FTLB Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 17/19] MIPS: Add default case for the FTLB enable/disable code Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 18/19] MIPS: kernel: cpu-probe: Fix VTLB/FTLB configuration for R6 Markos Chandras
2015-07-09 9:40 ` Markos Chandras
2015-07-09 9:40 ` [PATCH 19/19] MIPS: Set up FTLB probability for I6400 Markos Chandras
2015-07-09 9:40 ` Markos Chandras
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