Date: Mon, 18 Apr 2005 14:27:53 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> Cc: Eric Anderson <anderson@centtech.com> Subject: Re: powerd(8) Message-ID: <2428.1113827273@critter.freebsd.dk> In-Reply-To: Your message of "Mon, 18 Apr 2005 14:19:14 %2B0200." <2304.1113826754@critter.freebsd.dk>
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In message <2304.1113826754@critter.freebsd.dk>, "Poul-Henning Kamp" writes:
>In message <4263A33A.3030201@centtech.com>, Eric Anderson writes:
>>Lukas Ertl wrote:
>>
>>There's been some discussion on the -mobile list (I believe) about
>>this kind of thing before. I think powerd is currently running with
>>a 'best shot' configuration, and I'm pretty sure that if anyone has
>>a better algorithm in a patch form for people to try, I'm certain the
>>good people with commit bits would easily commit a patched better version.
>
>I don't think a proportional approach will work in this case, the steps
>are too far apart.
>
>I also think the switch to full speed is wrong. Such see-saw
>algorithms waste far too much time decaying. A less steep flank
>should be used.
>
>For instance:
>
> if (idle > 90%)
> reduce clock one step.
> if (idle < 80%)
> increase clock two steps.
Here's a patch which implements "phk" mode:
Index: powerd.c
===================================================================
RCS file: /home/ncvs/src/usr.sbin/powerd/powerd.c,v
retrieving revision 1.4
diff -u -r1.4 powerd.c
--- powerd.c 27 Feb 2005 01:58:49 -0000 1.4
+++ powerd.c 18 Apr 2005 12:26:03 -0000
@@ -50,6 +50,7 @@
enum modes_t {
MODE_MIN,
MODE_ADAPTIVE,
+ MODE_PHK,
MODE_MAX,
};
@@ -220,6 +221,8 @@
*mode = MODE_MAX;
else if (strcmp(arg, "adaptive") == 0)
*mode = MODE_ADAPTIVE;
+ else if (strcmp(arg, "phk") == 0)
+ *mode = MODE_PHK;
else
errx(1, "bad option: -%c %s", (char)ch, optarg);
}
@@ -377,6 +380,37 @@
if (read_usage_times(&idle, &total))
err(1, "read_usage_times");
+ if (mode == MODE_PHK) {
+ for (i = 0; i < numfreqs - 1; i++) {
+ if (freqs[i] == curfreq)
+ break;
+ }
+ if (idle < (total * cpu_running_mark) / 100 &&
+ curfreq < freqs[0]) {
+ i -= 2;
+ if (i < 0)
+ i = 0;
+ if (vflag) {
+ printf("idle time < %d%%, increasing clock"
+ " speed from %d MHz to %d MHz\n",
+ cpu_running_mark, curfreq, freqs[i]);
+ }
+ if (set_freq(freqs[i]))
+ err(1, "error setting CPU frequency %d", freqs[i]);
+ } else if (idle > (total * cpu_idle_mark) / 100 &&
+ curfreq > freqs[numfreqs - 1]) {
+ i++;
+ if (vflag) {
+ printf("idle time > %d%%, decreasing clock"
+ " speed from %d MHz to %d MHz\n",
+ cpu_idle_mark, curfreq, freqs[i]);
+ }
+ if (set_freq(freqs[i]))
+ err(1, "error setting CPU frequency %d", freqs[i]);
+ }
+ continue;
+ }
+
/*
* If we're idle less than the active mark, jump the CPU to
* its fastest speed if we're not there yet. If we're idle
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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