Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756434Ab1FCVpy (ORCPT ); Fri, 3 Jun 2011 17:45:54 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:54663 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753622Ab1FCVpw (ORCPT ); Fri, 3 Jun 2011 17:45:52 -0400 Date: Fri, 3 Jun 2011 14:45:40 -0700 From: Andrew Morton To: David Daney Cc: Sameer Nanda , ext-phil.2.carmody@nokia.com, Tim.Deegan@citrix.com, jbeulich@novell.com, snanda@google.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] init: skip calibration delay if previously done Message-Id: <20110603144540.d182c231.akpm@linux-foundation.org> In-Reply-To: <4DE94D31.3040104@caviumnetworks.com> References: <1306279146-23487-1-git-send-email-snanda@chromium.org> <20110603140054.a0f1859d.akpm@linux-foundation.org> <4DE94D31.3040104@caviumnetworks.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4342 Lines: 123 On Fri, 03 Jun 2011 14:08:01 -0700 David Daney wrote: > On 06/03/2011 02:00 PM, Andrew Morton wrote: > > On Tue, 24 May 2011 16:19:06 -0700 > > Sameer Nanda wrote: > > > >> For each CPU, do the calibration delay only once. For subsequent calls, > >> use the cached per-CPU value of loops_per_jiffy. > >> > >> This saves about 200ms of resume time on dual core Intel Atom N5xx based > >> systems. This helps bring down the kernel resume time on such systems from > >> about 500ms to about 300ms. > >> > >> Signed-off-by: Sameer Nanda > >> --- > >> init/calibrate.c | 10 +++++++++- > >> 1 files changed, 9 insertions(+), 1 deletions(-) > >> > >> diff --git a/init/calibrate.c b/init/calibrate.c > >> index 76ac919..47d3408 100644 > >> --- a/init/calibrate.c > >> +++ b/init/calibrate.c > >> @@ -183,11 +183,18 @@ recalibrate: > >> return lpj; > >> } > >> > >> +DEFINE_PER_CPU(unsigned long, cpu_loops_per_jiffy) = { 0 }; > >> + > >> void __cpuinit calibrate_delay(void) > >> { > >> static bool printed; > >> + int this_cpu = smp_processor_id(); > >> > >> - if (preset_lpj) { > >> + if (per_cpu(cpu_loops_per_jiffy, this_cpu)) { > >> + loops_per_jiffy = per_cpu(cpu_loops_per_jiffy, this_cpu); > >> + pr_info("Calibrating delay loop (skipped) " > >> + "already calibrated this CPU previously.. "); > > That wording seems a little redundant, and there are two '.' at the end. > > How about: > s/"already calibrated this CPU previously.. "/", this CPU previously > calibrated."/ > Pedant ;) --- a/init/calibrate.c~init-skip-calibration-delay-if-previously-done-fix-fix +++ a/init/calibrate.c @@ -256,7 +256,7 @@ void __cpuinit calibrate_delay(void) if (per_cpu(cpu_loops_per_jiffy, this_cpu)) { loops_per_jiffy = per_cpu(cpu_loops_per_jiffy, this_cpu); pr_info("Calibrating delay loop (skipped) " - "already calibrated this CPU previously.. "); + "already calibrated this CPU"); } else if (preset_lpj) { loops_per_jiffy = preset_lpj; if (!printed) _ But the whole thing is a bit weird. Does this look better? From: Andrew Morton Make these messages more gramatically pleasing, more consistent and remove strange ellipses. Cc: Andrew Worsley Cc: Phil Carmody Cc: Sameer Nanda Cc: David Daney Signed-off-by: Andrew Morton --- init/calibrate.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff -puN init/calibrate.c~init-calibratec-calibrate_delay-tidy-up-the-pr_info-messages init/calibrate.c --- a/init/calibrate.c~init-calibratec-calibrate_delay-tidy-up-the-pr_info-messages +++ a/init/calibrate.c @@ -255,24 +255,24 @@ void __cpuinit calibrate_delay(void) if (per_cpu(cpu_loops_per_jiffy, this_cpu)) { loops_per_jiffy = per_cpu(cpu_loops_per_jiffy, this_cpu); - pr_info("Calibrating delay loop (skipped) " - "already calibrated this CPU"); + pr_info("Calibrating delay loop. Skipped: already calibrated " + "this CPU"); } else if (preset_lpj) { loops_per_jiffy = preset_lpj; if (!printed) - pr_info("Calibrating delay loop (skipped) " - "preset value.. "); + pr_info("Calibrating delay loop. Skipped: " + "preset value"); } else if ((!printed) && lpj_fine) { loops_per_jiffy = lpj_fine; - pr_info("Calibrating delay loop (skipped), " - "value calculated using timer frequency.. "); + pr_info("Calibrating delay loop. Skipped: value calculated " + "using timer frequency"); } else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) { if (!printed) - pr_info("Calibrating delay using timer " - "specific routine.. "); + pr_info("Calibrating delay loop using timer-specific " + "routine"); } else { if (!printed) - pr_info("Calibrating delay loop... "); + pr_info("Calibrating delay loop"); loops_per_jiffy = calibrate_delay_converge(); } per_cpu(cpu_loops_per_jiffy, this_cpu) = loops_per_jiffy; _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/