From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
To: Philippe Longepe <philippe.longepe@linux.intel.com>,
linux-pm@vger.kernel.org
Cc: rafael@kernel.org
Subject: Re: [PATCH V5 1/4] Remove extra conversions in pid calculation
Date: Mon, 07 Mar 2016 13:30:50 -0800 [thread overview]
Message-ID: <1457386250.4361.7.camel@linux.intel.com> (raw)
In-Reply-To: <1457249646-23072-2-git-send-email-philippe.longepe@linux.intel.com>
On Sun, 2016-03-06 at 08:34 +0100, Philippe Longepe wrote:
> pid->setpoint and pid->deadband can be initialize in float so we
> can remove the int_tofp in pid_calc.
Rafael had some comments on this patch:
"s/initialize/initialized/
> can remove the int_tofp in pid_calc.
This is not "float", but "fixed point".
Also "avoid" rather than "remove".
"
Not sure if Rafael is OK without change.
> Signed-off-by: Philippe Longepe <philippe.longepe@linux.intel.com>
> ---
> drivers/cpufreq/intel_pstate.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/intel_pstate.c
> b/drivers/cpufreq/intel_pstate.c
> index eb0aef0..114e4e0 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -198,8 +198,8 @@ static struct perf_limits *limits =
> &powersave_limits;
>
> static inline void pid_reset(struct _pid *pid, int setpoint, int
> busy,
> int deadband, int integral) {
> - pid->setpoint = setpoint;
> - pid->deadband = deadband;
> + pid->setpoint = int_tofp(setpoint);
> + pid->deadband = int_tofp(deadband);
> pid->integral = int_tofp(integral);
> pid->last_err = int_tofp(setpoint) - int_tofp(busy);
> }
> @@ -225,9 +225,9 @@ static signed int pid_calc(struct _pid *pid,
> int32_t busy)
> int32_t pterm, dterm, fp_error;
> int32_t integral_limit;
>
> - fp_error = int_tofp(pid->setpoint) - busy;
> + fp_error = pid->setpoint - busy;
>
> - if (abs(fp_error) <= int_tofp(pid->deadband))
> + if (abs(fp_error) <= pid->deadband)
> return 0;
>
> pterm = mul_fp(pid->p_gain, fp_error);
next prev parent reply other threads:[~2016-03-07 21:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-06 7:34 [PATCH V5 0/4] Reduce the intel_pstate timer overhead Philippe Longepe
2016-03-06 7:34 ` [PATCH V5 1/4] Remove extra conversions in pid calculation Philippe Longepe
2016-03-07 21:30 ` Srinivas Pandruvada [this message]
2016-03-06 7:34 ` [PATCH V5 2/4] Optimize calculation for max/min_perf_adj Philippe Longepe
2016-03-07 21:35 ` Srinivas Pandruvada
2016-03-06 7:34 ` [PATCH V5 3/4] Move the intel_pstate_calc_busy into get_target_pstate_use_performance Philippe Longepe
2016-03-07 21:36 ` Srinivas Pandruvada
2016-03-06 7:34 ` [PATCH V5 4/4] intel_pstate: Remove the freq calculation from the intel_pstate_calc_busy function Philippe Longepe
2016-03-07 21:42 ` Srinivas Pandruvada
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