From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-x241.google.com (mail-pg0-x241.google.com [IPv6:2607:f8b0:400e:c05::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wmc5w1hPGzDqL2 for ; Tue, 13 Jun 2017 01:20:20 +1000 (AEST) Received: by mail-pg0-x241.google.com with SMTP id v18so14536120pgb.3 for ; Mon, 12 Jun 2017 08:20:20 -0700 (PDT) Date: Tue, 13 Jun 2017 01:20:06 +1000 From: Nicholas Piggin To: Gautham R Shenoy Cc: linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 10/14] powerpc/64s: cpuidle set polling before enabling irqs Message-ID: <20170613012006.387e19d5@roar.ozlabs.ibm.com> In-Reply-To: <20170612151025.GG10921@in.ibm.com> References: <20170611235835.7400-1-npiggin@gmail.com> <20170611235835.7400-11-npiggin@gmail.com> <20170612151025.GG10921@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 12 Jun 2017 20:40:25 +0530 Gautham R Shenoy wrote: > On Mon, Jun 12, 2017 at 09:58:31AM +1000, Nicholas Piggin wrote: > > local_irq_enable can cause interrupts to be taken which could > > take significant amount of processing time. The idle process > > should set its polling flag before this, so another process that > > wakes it during this time will not have to send an IPI. > > > > Expand the TIF_POLLING_NRFLAG coverage to as large as possible. > > > > Signed-off-by: Nicholas Piggin > > Looks good. Were you able to see this make a difference in any of the > tests ? No I didn't measure a difference or have a test case where this was noticable. I think on a workload with some IO interrupts as well as cross-CPU wakeups, then statistically we should see some improvement in IPI rates with this patch. Thanks, Nick