From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de
Subject: Re: [RFC Patch v1 32/55] ARC: [optim] Cache "current" in Register r25
Date: Thu, 15 Nov 2012 15:52:43 +0530 [thread overview]
Message-ID: <50A4C273.10102@synopsys.com> (raw)
In-Reply-To: <201211121350.12810.arnd@arndb.de>
On Monday 12 November 2012 07:20 PM, Arnd Bergmann wrote:
> On Monday 12 November 2012, Vineet.Gupta1@synopsys.com wrote:
>> endmenu # "Platform Board Configuration"
>>
>> +config ARC_CURR_IN_REG
>> + bool "Dedicate Register r25 for current_task pointer"
>> + default y
>> + help
>> + This reserved Register R25 to point to Current Task in
>> + kernel mode. This saves memory access for each such access
>> +
> This looks like a useful feature if you have 32 GPRs, but why make it
> optional? Are there cases where you would disable it?
Since it touched the low level guts of port, it made sense to start with
a config option in initial implementation. But I've kept it that way
since it annotates the code nicely and implicitly documents how to do
this for any other register + data structure.
> Another alternative to caching "current" would be to cache the per-cpu
> offset, and calculate current from that one.
Good tip - I'll add this to my TODO list -
> Arnd
next prev parent reply other threads:[~2012-11-15 10:22 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-12 11:48 [RFC Patch v1 00/55] Addons to Synopsys ARC Linux kernel Port Vineet.Gupta1
2012-11-12 11:48 ` [RFC Patch v1 32/55] ARC: [optim] Cache "current" in Register r25 Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 13:50 ` Arnd Bergmann
2012-11-15 10:22 ` Vineet Gupta [this message]
2012-11-15 10:22 ` Vineet Gupta
2012-11-12 11:48 ` [RFC Patch v1 33/55] ARC: ptrace support Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 13:51 ` Arnd Bergmann
2012-11-12 13:51 ` Arnd Bergmann
2012-11-15 10:24 ` Vineet Gupta
2012-11-15 10:24 ` Vineet Gupta
2012-11-15 11:56 ` Arnd Bergmann
2012-11-12 11:48 ` [RFC Patch v1 34/55] ARC: futex Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 11:48 ` [RFC Patch v1 35/55] ARC: oprofile support Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 11:48 ` [RFC Patch v1 36/55] ARC: ARCompact 2 levels IRQ (high/low priority) Handling Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 11:48 ` [RFC Patch v1 37/55] ARC: dynamic loadable module support Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 13:53 ` Arnd Bergmann
2012-11-15 10:28 ` Vineet Gupta
2012-11-12 11:48 ` [RFC Patch v1 38/55] ARC: Low level event capture/logging Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 13:55 ` Arnd Bergmann
2012-11-15 10:40 ` Vineet Gupta
2012-11-15 12:04 ` Arnd Bergmann
2012-12-20 6:22 ` Vineet Gupta
2012-11-12 11:48 ` [RFC Patch v1 39/55] ARC: kernel diagnostics: show_regs() etc Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 11:48 ` [RFC Patch v1 40/55] ARC: SMP support Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 11:48 ` [RFC Patch v1 41/55] ARC: dwarf2 stack unwinder Vineet.Gupta1
2012-11-12 11:48 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 42/55] ARC: stacktracing APIs based on dw2 unwinder Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 43/55] ARC: disassembly (needed by kprobes/kgdb/unaligned-access-emul) Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 44/55] ARC: kprobes support Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 45/55] ARC: unaligned access emulation Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 14:00 ` Arnd Bergmann
2012-12-20 6:59 ` Vineet Gupta
2012-12-20 10:30 ` Vineet Gupta
2012-12-20 10:34 ` Geert Uytterhoeven
2012-12-20 11:11 ` [PATCH] sysctl: some arch specific unaligned access knobs made generic Vineet.Gupta1
2012-12-20 11:11 ` [PATCH] sysctl: convert arch specific unaligned access regulators to generic ones Vineet.Gupta1
2013-01-03 6:47 ` [RESEND PATCH] Convert IA64 sysctl to generic Vineet Gupta
2013-01-03 6:47 ` Vineet Gupta
2013-01-03 6:47 ` [RESEND PATCH] sysctl: Enable IA64 "ignore-unaligned-usertrap" to be used cross-arch Vineet Gupta
2013-01-03 6:47 ` Vineet Gupta
2013-01-08 23:43 ` Tony Luck
2013-01-08 23:43 ` Tony Luck
2013-01-09 14:14 ` Vineet Gupta
2013-01-09 14:36 ` [PATCH v2] " Vineet Gupta
2013-01-09 18:55 ` Tony Luck
2013-01-09 18:55 ` Tony Luck
2013-01-09 21:03 ` Eric W. Biederman
2013-01-09 21:03 ` Eric W. Biederman
2013-01-10 4:13 ` Vineet Gupta
2013-01-03 6:59 ` [RESEND PATCH] Convert PARISC sysctl to be generic Vineet Gupta
2013-01-03 6:59 ` [RESEND PATCH] sysctl: Enable PARISC "unaligned-trap" to be used cross-arch Vineet Gupta
2013-01-15 22:03 ` Helge Deller
2013-01-15 22:03 ` Helge Deller
2012-12-20 8:08 ` [RFC Patch v1 45/55] ARC: unaligned access emulation Vineet Gupta
2012-12-20 8:51 ` Arnd Bergmann
2012-11-12 11:49 ` [RFC Patch v1 46/55] ARC: kgdb support Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 47/55] ARC: startup #2: Verbose Boot reporting / feature verification Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 48/55] ARC: [plat-arfpga] BVCI Latency Unit setup Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 14:02 ` Arnd Bergmann
2013-01-17 5:08 ` Vineet Gupta
2012-11-12 11:49 ` [RFC Patch v1 49/55] perf, ARC: Enable building perf tools for ARC Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 50/55] ARC: perf support (software counters only) Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 51/55] modpost: Ignore ARC specific non-alloc section Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-12-27 10:47 ` [RESEND PATCH] modpost: For ARC Port submission Vineet Gupta
2012-12-27 10:47 ` Vineet Gupta
2012-12-27 10:47 ` [PATCH] modpost: Ignore ARC specific non-alloc sections Vineet Gupta
2012-12-27 20:48 ` Sam Ravnborg
2012-12-28 4:42 ` Vineet Gupta
2012-12-28 4:42 ` Vineet Gupta
2013-01-02 0:49 ` Rusty Russell
2013-01-02 0:49 ` Rusty Russell
2013-01-02 5:16 ` Vineet Gupta
2012-11-12 11:49 ` [RFC Patch v1 52/55] ARC: Support for single cycle Close Coupled Mem (CCM) Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 14:10 ` Arnd Bergmann
2013-01-17 5:09 ` Vineet Gupta
2013-01-17 10:53 ` Arnd Bergmann
2012-11-12 11:49 ` [RFC Patch v1 53/55] ARC: Hostlink Pseudo-Driver for Metaware Debugger Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 54/55] ARC: [plat-arcfpga] defconfig Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
2012-11-12 11:49 ` [RFC Patch v1 55/55] ARC: Add self to MAINTAINERS Vineet.Gupta1
2012-11-12 11:49 ` Vineet.Gupta1
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