From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e8.ny.us.ibm.com (e8.ny.us.ibm.com [32.97.182.138]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 80EBC1A03E5 for ; Tue, 20 Jan 2015 22:27:06 +1100 (AEDT) Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 20 Jan 2015 06:27:03 -0500 Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 4A49738C8041 for ; Tue, 20 Jan 2015 06:27:02 -0500 (EST) Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t0KBR2WG28835886 for ; Tue, 20 Jan 2015 11:27:02 GMT Received: from d01av03.pok.ibm.com (localhost [127.0.0.1]) by d01av03.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t0KBR1hX011374 for ; Tue, 20 Jan 2015 06:27:02 -0500 Message-ID: <54BE3B79.9070004@linux.vnet.ibm.com> Date: Tue, 20 Jan 2015 16:56:49 +0530 From: Preeti U Murthy MIME-Version: 1.0 To: Michael Ellerman , rafael.j.wysocki@intel.com Subject: Re: cpuidle/powernv: Read target_residency value of idle states from DT if available References: <20150120054506.F13591402E0@ozlabs.org> In-Reply-To: <20150120054506.F13591402E0@ozlabs.org> Content-Type: text/plain; charset=UTF-8 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 01/20/2015 11:15 AM, Michael Ellerman wrote: > On Mon, 2015-19-01 at 11:32:51 UTC, Preeti U Murthy wrote: >> The device tree now exposes the residency values for different idle states. Read >> these values instead of calculating residency from the latency values. The values >> exposed in the DT are validated for optimal power efficiency. However to maintain >> compatibility with the older firmware code which does not expose residency >> values, use default values as a fallback mechanism. While at it, clump >> the common parts of device tree parsing into one chunk. >> >> Signed-off-by: Preeti U Murthy >> --- >> >> drivers/cpuidle/cpuidle-powernv.c | 39 ++++++++++++++++++++++++------------- >> 1 file changed, 25 insertions(+), 14 deletions(-) >> >> diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c >> index 2726663..9e732e1 100644 >> --- a/drivers/cpuidle/cpuidle-powernv.c >> +++ b/drivers/cpuidle/cpuidle-powernv.c >> @@ -162,7 +162,8 @@ static int powernv_add_idle_states(void) >> int dt_idle_states; >> const __be32 *idle_state_flags; >> const __be32 *idle_state_latency; >> - u32 len_flags, flags, latency_ns; >> + const __be32 *idle_state_residency; >> + u32 len_flags, flags, latency_ns, residency_ns; >> int i; >> >> /* Currently we have snooze statically defined */ >> @@ -186,14 +187,21 @@ static int powernv_add_idle_states(void) >> return nr_idle_states; >> } >> >> + idle_state_residency = of_get_property(power_mgt, >> + "ibm,cpu-idle-state-residency-ns", NULL); >> + if (!idle_state_residency) { >> + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-residency-ns\n"); >> + pr_warn("Falling back to default values\n"); >> + } > > This would be better done with something like: > > rc = of_read_property_u32(power_mgt, "ibm,cpu-idle-state-residency-ns", &residency_ns); > if (!rc) { > pr_info("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns\n"); > residency_ns = 300000; > } This looks like a better API, but the default residency values are different for each idle state. So perhaps a patch like the below ? --------------------------Start Patch------------------------------------------ From: Preeti U Murthy --- drivers/cpuidle/cpuidle-powernv.c | 54 +++++++++++++++++++++++-------------- 1 file changed, 33 insertions(+), 21 deletions(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index aedec09..2031560 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -159,9 +160,9 @@ static int powernv_add_idle_states(void) int nr_idle_states = 1; /* Snooze */ int dt_idle_states; const __be32 *idle_state_flags; - const __be32 *idle_state_latency; - u32 len_flags, flags, latency_ns; - int i; + u32 len_flags, flags; + u32 *latency_ns, *residency_ns; + int i, rc; /* Currently we have snooze statically defined */ @@ -177,34 +178,39 @@ static int powernv_add_idle_states(void) return nr_idle_states; } - idle_state_latency = of_get_property(power_mgt, - "ibm,cpu-idle-state-latencies-ns", NULL); - if (!idle_state_latency) { + dt_idle_states = len_flags / sizeof(u32); + + latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL); + rc = of_property_read_u32(power_mgt, + "ibm,cpu-idle-state-latencies-ns", latency_ns); + if (rc) { pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n"); return nr_idle_states; } - dt_idle_states = len_flags / sizeof(u32); + residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL); + rc = of_property_read_u32(power_mgt, + "ibm,cpu-idle-state-residency-ns", residency_ns); + if (rc) { + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-residency-ns\n"); + pr_warn("Falling back to default values\n"); + } + for (i = 0; i < dt_idle_states; i++) { flags = be32_to_cpu(idle_state_flags[i]); - - /* Cpuidle accepts exit_latency in us and we estimate - * target residency to be 10x exit_latency + /* + * Cpuidle accepts exit_latency and target_residency in us. + * Use default target_residency values if f/w does not expose it. */ - latency_ns = be32_to_cpu(idle_state_latency[i]); if (flags & OPAL_PM_NAP_ENABLED) { /* Add NAP state */ strcpy(powernv_states[nr_idle_states].name, "Nap"); strcpy(powernv_states[nr_idle_states].desc, "Nap"); powernv_states[nr_idle_states].flags = 0; - powernv_states[nr_idle_states].exit_latency = - ((unsigned int)latency_ns) / 1000; - powernv_states[nr_idle_states].target_residency = - ((unsigned int)latency_ns / 100); + powernv_states[nr_idle_states].target_residency = 100; powernv_states[nr_idle_states].enter = &nap_loop; - nr_idle_states++; } if (flags & OPAL_PM_SLEEP_ENABLED || @@ -213,13 +219,19 @@ static int powernv_add_idle_states(void) strcpy(powernv_states[nr_idle_states].name, "FastSleep"); strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; - powernv_states[nr_idle_states].exit_latency = - ((unsigned int)latency_ns) / 1000; - powernv_states[nr_idle_states].target_residency = - ((unsigned int)latency_ns / 100); + powernv_states[nr_idle_states].target_residency = 300000; powernv_states[nr_idle_states].enter = &fastsleep_loop; - nr_idle_states++; } + + powernv_states[nr_idle_states].exit_latency = + ((unsigned int)latency_ns[i]) / 1000; + + if (!rc) { + powernv_states[nr_idle_states].target_residency = + ((unsigned int)residency_ns[i]) / 1000; + } + + nr_idle_states++; } return nr_idle_states; Regards Preeti U Murthy > > cheers > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev >