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Annotation of sys/arch/amd64/amd64/mp_setperf.c, Revision 1.1

1.1     ! nbrk        1: /* $OpenBSD: mp_setperf.c,v 1.1 2007/05/06 03:37:08 gwk Exp $ */
        !             2: /*
        !             3:  * Copyright (c) 2007 Gordon Willem Klok <gwk@openbsd.org>
        !             4:  *
        !             5:  * Permission to use, copy, modify, and distribute this software for any
        !             6:  * purpose with or without fee is hereby granted, provided that the above
        !             7:  * copyright notice and this permission notice appear in all copies.
        !             8:  *
        !             9:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
        !            10:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            11:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
        !            12:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            13:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            14:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
        !            15:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            16:  */
        !            17:
        !            18: #include <sys/param.h>
        !            19: #include <sys/systm.h>
        !            20: #include <sys/sysctl.h>
        !            21: #include <sys/mutex.h>
        !            22:
        !            23: #include <machine/cpu.h>
        !            24:
        !            25: #include <machine/intr.h>
        !            26:
        !            27: struct mutex setperf_mp_mutex = MUTEX_INITIALIZER(IPL_HIGH);
        !            28:
        !            29: /* underlying setperf mechanism e.g. k8_powernow_setperf() */
        !            30: void (*ul_setperf)(int);
        !            31:
        !            32: #define MP_SETPERF_STEADY      0       /* steady state - normal operation */
        !            33: #define MP_SETPERF_INTRANSIT   1       /* in transition */
        !            34: #define MP_SETPERF_PROCEED     2       /* proceed with transition */
        !            35: #define MP_SETPERF_FINISH      3       /* return from IPI */
        !            36:
        !            37:
        !            38: /* protected by setperf_mp_mutex */
        !            39: volatile int mp_setperf_state = MP_SETPERF_STEADY;
        !            40: volatile int mp_perflevel;
        !            41:
        !            42: void mp_setperf(int);
        !            43:
        !            44: void
        !            45: mp_setperf(int level)
        !            46: {
        !            47:        CPU_INFO_ITERATOR cii;
        !            48:        struct cpu_info *ci;
        !            49:        int notready, s;
        !            50:
        !            51:        if (mp_setperf_state == MP_SETPERF_STEADY) {
        !            52:                mtx_enter(&setperf_mp_mutex);
        !            53:                mp_perflevel = level;
        !            54:
        !            55:                curcpu()->ci_setperf_state = CI_SETPERF_INTRANSIT;
        !            56:                /* ask all other processors to drop what they are doing */
        !            57:                CPU_INFO_FOREACH(cii, ci) {
        !            58:                        if (ci->ci_setperf_state != CI_SETPERF_INTRANSIT) {
        !            59:                                ci->ci_setperf_state =
        !            60:                                    CI_SETPERF_SHOULDSTOP;
        !            61:                                x86_send_ipi(ci, X86_IPI_SETPERF);
        !            62:                        }
        !            63:                }
        !            64:
        !            65:
        !            66:                /* Loop until all processors report ready */
        !            67:                do {
        !            68:                        CPU_INFO_FOREACH(cii, ci) {
        !            69:                                if ((notready = (ci->ci_setperf_state
        !            70:                                    != CI_SETPERF_INTRANSIT)))
        !            71:                                        break;
        !            72:                        }
        !            73:                } while (notready);
        !            74:
        !            75:                mp_setperf_state = MP_SETPERF_PROCEED; /* release the hounds */
        !            76:
        !            77:                s = splipi();
        !            78:
        !            79:                ul_setperf(mp_perflevel);
        !            80:
        !            81:                splx(s);
        !            82:
        !            83:                curcpu()->ci_setperf_state = CI_SETPERF_DONE;
        !            84:                /* Loop until all processors report done */
        !            85:                do {
        !            86:                        CPU_INFO_FOREACH(cii, ci) {
        !            87:                                if ((notready = (ci->ci_setperf_state
        !            88:                                    != CI_SETPERF_DONE)))
        !            89:                                        break;
        !            90:                        }
        !            91:                } while (notready);
        !            92:
        !            93:                mp_setperf_state = MP_SETPERF_FINISH;
        !            94:                /* delay a little for potential straglers */
        !            95:                DELAY(2);
        !            96:                curcpu()->ci_setperf_state = CI_SETPERF_READY;
        !            97:                mp_setperf_state = MP_SETPERF_STEADY; /* restore normallity */
        !            98:                mtx_leave(&setperf_mp_mutex);
        !            99:        }
        !           100:
        !           101: }
        !           102:
        !           103: void
        !           104: x86_setperf_ipi(struct cpu_info *ci)
        !           105: {
        !           106:
        !           107:        if (ci->ci_setperf_state == CI_SETPERF_SHOULDSTOP)
        !           108:                ci->ci_setperf_state = CI_SETPERF_INTRANSIT;
        !           109:
        !           110:        while (mp_setperf_state != MP_SETPERF_PROCEED)
        !           111:                ;
        !           112:
        !           113:        ul_setperf(mp_perflevel);
        !           114:
        !           115:        ci->ci_setperf_state = CI_SETPERF_DONE;
        !           116:
        !           117:        while (mp_setperf_state != MP_SETPERF_FINISH)
        !           118:                ;
        !           119:        ci->ci_setperf_state = CI_SETPERF_READY;
        !           120: }
        !           121:
        !           122: void
        !           123: mp_setperf_init()
        !           124: {
        !           125:        CPU_INFO_ITERATOR cii;
        !           126:        struct cpu_info *ci;
        !           127:
        !           128:
        !           129:        if (!cpu_setperf)
        !           130:                return;
        !           131:        ul_setperf = cpu_setperf;
        !           132:
        !           133:        cpu_setperf = mp_setperf;
        !           134:
        !           135:        CPU_INFO_FOREACH(cii, ci) {
        !           136:                ci->ci_setperf_state = CI_SETPERF_READY;
        !           137:        }
        !           138:        mtx_init(&setperf_mp_mutex, IPL_HIGH);
        !           139: }