From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp02.in.ibm.com (e28smtp02.in.ibm.com [122.248.162.2]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 6326C1A0551 for ; Fri, 29 May 2015 22:32:28 +1000 (AEST) Received: from /spool/local by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 29 May 2015 18:02:24 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id A825E394005E for ; Fri, 29 May 2015 18:02:23 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay03.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t4TCWMWQ43253932 for ; Fri, 29 May 2015 18:02:23 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t4TCWET6025132 for ; Fri, 29 May 2015 18:02:14 +0530 From: Shilpasri G Bhat To: linuxppc-dev@lists.ozlabs.org Cc: anton@samba.org, rjw@rjwysocki.net, preeti@linux.vnet.ibm.com, Daniel Lezcano , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Shilpasri G Bhat Subject: [PATCH] cpuidle: powernv/pseries: Decrease the snooze residency Date: Fri, 29 May 2015 18:02:08 +0530 Message-Id: <1432902728-31476-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The idle cpus which stay in snooze for a long period can degrade the perfomance of the sibling cpus. If the cpu stays in snooze for more than target residency of the next available idle state, then exit from snooze. This gives a chance to the cpuidle governor to re-evaluate the last idle state of the cpu to promote it to deeper idle states. Signed-off-by: Shilpasri G Bhat --- drivers/cpuidle/cpuidle-powernv.c | 12 ++++++++++++ drivers/cpuidle/cpuidle-pseries.c | 11 +++++++++++ 2 files changed, 23 insertions(+) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 5937207..1e3ef5e 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -29,18 +29,25 @@ struct cpuidle_driver powernv_idle_driver = { static int max_idle_state; static struct cpuidle_state *cpuidle_state_table; +static u64 snooze_timeout; +static bool snooze_timeout_en; static int snooze_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { + u64 snooze_exit_time; + local_irq_enable(); set_thread_flag(TIF_POLLING_NRFLAG); + snooze_exit_time = get_tb() + snooze_timeout; ppc64_runlatch_off(); while (!need_resched()) { HMT_low(); HMT_very_low(); + if (snooze_timeout_en && get_tb() > snooze_exit_time) + break; } HMT_medium(); @@ -252,6 +259,11 @@ static int powernv_idle_probe(void) cpuidle_state_table = powernv_states; /* Device tree can indicate more idle states */ max_idle_state = powernv_add_idle_states(); + if (max_idle_state > 1) { + snooze_timeout_en = true; + snooze_timeout = powernv_states[1].target_residency * + tb_ticks_per_usec; + } } else return -ENODEV; diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c index bb9e2b6..07135e0 100644 --- a/drivers/cpuidle/cpuidle-pseries.c +++ b/drivers/cpuidle/cpuidle-pseries.c @@ -27,6 +27,8 @@ struct cpuidle_driver pseries_idle_driver = { static int max_idle_state; static struct cpuidle_state *cpuidle_state_table; +static u64 snooze_timeout; +static bool snooze_timeout_en; static inline void idle_loop_prolog(unsigned long *in_purr) { @@ -58,14 +60,18 @@ static int snooze_loop(struct cpuidle_device *dev, int index) { unsigned long in_purr; + u64 snooze_exit_time; idle_loop_prolog(&in_purr); local_irq_enable(); set_thread_flag(TIF_POLLING_NRFLAG); + snooze_exit_time = get_tb() + snooze_timeout; while (!need_resched()) { HMT_low(); HMT_very_low(); + if (snooze_timeout_en && get_tb() > snooze_exit_time) + break; } HMT_medium(); @@ -244,6 +250,11 @@ static int pseries_idle_probe(void) } else return -ENODEV; + if (max_idle_state > 1) { + snooze_timeout_en = true; + snooze_timeout = cpuidle_state_table[1].target_residency * + tb_ticks_per_usec; + } return 0; } -- 1.9.3