skdim.c

linux-2.6.15.6

/******************************************************************************
 *
 * Name:	skdim.c
 * Project:	GEnesis, PCI Gigabit Ethernet Adapter
 * Version:	$Revision: 1.5 $
 * Date:	$Date: 2003/11/28 12:55:40 $
 * Purpose:	All functions to maintain interrupt moderation
 *
 ******************************************************************************/

/******************************************************************************
 *
 *	(C)Copyright 1998-2002 SysKonnect GmbH.
 *	(C)Copyright 2002-2003 Marvell.
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	The information in this file is provided "AS IS" without warranty.
 *
 ******************************************************************************/

/******************************************************************************
 *
 * Description:
 *
 * This module is intended to manage the dynamic interrupt moderation on both   
 * GEnesis and Yukon adapters.
 *
 * Include File Hierarchy:
 *
 *	"skdrv1st.h"
 *	"skdrv2nd.h"
 *
 ******************************************************************************/

#ifndef	lint
static const char SysKonnectFileId[] =
	"@(#) $Id: skdim.c,v 1.5 2003/11/28 12:55:40 rroesler Exp $ (C) SysKonnect.";
#endif

#define __SKADDR_C

#ifdef __cplusplus
#error C++ is not yet supported.
extern "C" {
#endif

/*******************************************************************************
**
** Includes
**
*******************************************************************************/

#ifndef __INC_SKDRV1ST_H
#include "h/skdrv1st.h"
#endif

#ifndef __INC_SKDRV2ND_H
#include "h/skdrv2nd.h"
#endif

#include	<linux/kernel_stat.h>

/*******************************************************************************
**
** Defines
**
*******************************************************************************/

/*******************************************************************************
**
** Typedefs
**
*******************************************************************************/

/*******************************************************************************
**
** Local function prototypes 
**
*******************************************************************************/

static unsigned int GetCurrentSystemLoad(SK_AC *pAC);
static SK_U64       GetIsrCalls(SK_AC *pAC);
static SK_BOOL      IsIntModEnabled(SK_AC *pAC);
static void         SetCurrIntCtr(SK_AC *pAC);
static void         EnableIntMod(SK_AC *pAC); 
static void         DisableIntMod(SK_AC *pAC);
static void         ResizeDimTimerDuration(SK_AC *pAC);
static void         DisplaySelectedModerationType(SK_AC *pAC);
static void         DisplaySelectedModerationMask(SK_AC *pAC);
static void         DisplayDescrRatio(SK_AC *pAC);

/*******************************************************************************
**
** Global variables
**
*******************************************************************************/

/*******************************************************************************
**
** Local variables
**
*******************************************************************************/

/*******************************************************************************
**
** Global functions 
**
*******************************************************************************/

/*******************************************************************************
** Function     : SkDimModerate
** Description  : Called in every ISR to check if moderation is to be applied
**                or not for the current number of interrupts
** Programmer   : Ralph Roesler
** Last Modified: 22-mar-03
** Returns      : void (!)
** Notes        : -
*******************************************************************************/

void 
SkDimModerate(SK_AC *pAC) {
    unsigned int CurrSysLoad    = 0;  /* expressed in percent */
    unsigned int LoadIncrease   = 0;  /* expressed in percent */
    SK_U64       ThresholdInts  = 0;
    SK_U64       IsrCallsPerSec = 0;

#define M_DIMINFO pAC->DynIrqModInfo

    if (!IsIntModEnabled(pAC)) {
        if (M_DIMINFO.IntModTypeSelect == C_INT_MOD_DYNAMIC) {
            CurrSysLoad = GetCurrentSystemLoad(pAC);
            if (CurrSysLoad > 75) {
                    /* 
                    ** More than 75% total system load! Enable the moderation 
                    ** to shield the system against too many interrupts.
                    */
                    EnableIntMod(pAC);
            } else if (CurrSysLoad > M_DIMINFO.PrevSysLoad) {
                LoadIncrease = (CurrSysLoad - M_DIMINFO.PrevSysLoad);
                if (LoadIncrease > ((M_DIMINFO.PrevSysLoad *
                                         C_INT_MOD_ENABLE_PERCENTAGE) / 100)) {
                    if (CurrSysLoad > 10) {
                        /* 
                        ** More than 50% increase with respect to the 
                        ** previous load of the system. Most likely this 
                        ** is due to our ISR-proc...
                        */
                        EnableIntMod(pAC);
                    }
                }
            } else {
                /*
                ** Neither too much system load at all nor too much increase
                ** with respect to the previous system load. Hence, we can leave
                ** the ISR-handling like it is without enabling moderation.
                */
            }
            M_DIMINFO.PrevSysLoad = CurrSysLoad;
        }   
    } else {
        if (M_DIMINFO.IntModTypeSelect == C_INT_MOD_DYNAMIC) {
            ThresholdInts  = ((M_DIMINFO.MaxModIntsPerSec *
                                   C_INT_MOD_DISABLE_PERCENTAGE) / 100);
            IsrCallsPerSec = GetIsrCalls(pAC);
            if (IsrCallsPerSec <= ThresholdInts) {
                /* 
                ** The number of interrupts within the last second is 
                ** lower than the disable_percentage of the desried 
                ** maxrate. Therefore we can disable the moderation.
                */
                DisableIntMod(pAC);
                M_DIMINFO.MaxModIntsPerSec = 
                   (M_DIMINFO.MaxModIntsPerSecUpperLimit +
                    M_DIMINFO.MaxModIntsPerSecLowerLimit) / 2;
            } else {
                /*
                ** The number of interrupts per sec is the same as expected.
                ** Evalulate the descriptor-ratio. If it has changed, a resize 
                ** in the moderation timer might be usefull
                */
                if (M_DIMINFO.AutoSizing) {
                    ResizeDimTimerDuration(pAC);
                }
            }
        }
    }

    /*
    ** Some information to the log...
    */
    if (M_DIMINFO.DisplayStats) {
        DisplaySelectedModerationType(pAC);
        DisplaySelectedModerationMask(pAC);
        DisplayDescrRatio(pAC);
    }

    M_DIMINFO.NbrProcessedDescr = 0; 
    SetCurrIntCtr(pAC);
}

/*******************************************************************************
** Function     : SkDimStartModerationTimer
** Description  : Starts the audit-timer for the dynamic interrupt moderation
** Programmer   : Ralph Roesler
** Last Modified: 22-mar-03
** Returns      : void (!)
** Notes        : -
*******************************************************************************/

void 
SkDimStartModerationTimer(SK_AC *pAC) {
    SK_EVPARA    EventParam;   /* Event struct for timer event */
 
    SK_MEMSET((char *) &EventParam, 0, sizeof(EventParam));
    EventParam.Para32[0] = SK_DRV_MODERATION_TIMER;
    SkTimerStart(pAC, pAC->IoBase, &pAC->DynIrqModInfo.ModTimer,
                 SK_DRV_MODERATION_TIMER_LENGTH,
                 SKGE_DRV, SK_DRV_TIMER, EventParam);
}

/*******************************************************************************
** Function     : SkDimEnableModerationIfNeeded
** Description  : Either enables or disables moderation
** Programmer   : Ralph Roesler
** Last Modified: 22-mar-03
** Returns      : void (!)
** Notes        : This function is called when a particular adapter is opened
**                There is no Disable function, because when all interrupts 
**                might be disable, the moderation timer has no meaning at all
******************************************************************************/

void
SkDimEnableModerationIfNeeded(SK_AC *pAC) {

    if (M_DIMINFO.IntModTypeSelect == C_INT_MOD_STATIC) {
        EnableIntMod(pAC);   /* notification print in this function */
    } else if (M_DIMINFO.IntModTypeSelect == C_INT_MOD_DYNAMIC) {
        SkDimStartModerationTimer(pAC);
        if (M_DIMINFO.DisplayStats) {
            printk("Dynamic moderation has been enabled\n");
        }
    } else {
        if (M_DIMINFO.DisplayStats) {
            printk("No moderation has been enabled\n");
        }
    }
}

/*******************************************************************************
** Function     : SkDimDisplayModerationSettings
** Description  : Displays the current settings regaring interrupt moderation
** Programmer   : Ralph Roesler
** Last Modified: 22-mar-03
** Returns      : void (!)
** Notes        : -
*******************************************************************************/

void 
SkDimDisplayModerationSettings(SK_AC *pAC) {
    DisplaySelectedModerationType(pAC);
    DisplaySelectedModerationMask(pAC);
}

/*******************************************************************************
**
** Local functions 
**
*******************************************************************************/

/*******************************************************************************
** Function     : GetCurrentSystemLoad
** Description  : Retrieves the current system load of the system. This load
**                is evaluated for all processors within the system.
** Programmer   : Ralph Roesler
** Last Modified: 22-mar-03
** Returns      : unsigned int: load expressed in percentage
** Notes        : The possible range being returned is from 0 up to 100.
**                Whereas 0 means 'no load at all' and 100 'system fully loaded'
**                It is impossible to determine what actually causes the system
**                to be in 100%, but maybe that is due to too much interrupts.
*******************************************************************************/

static unsigned int
GetCurrentSystemLoad(SK_AC *pAC) {
	unsigned long jif         = jiffies;
	unsigned int  UserTime    = 0;
	unsigned int  SystemTime  = 0;
	unsigned int  NiceTime    = 0;
	unsigned int  IdleTime    = 0;
	unsigned int  TotalTime   = 0;
	unsigned int  UsedTime    = 0;
	unsigned int  SystemLoad  = 0;

	/* unsigned int  NbrCpu      = 0; */

	/*
	** The following lines have been commented out, because
	** from kernel 2.5.44 onwards, the kernel-owned structure
	**
	**      struct kernel_stat kstat
	**
	** is not marked as an exported symbol in the file
	**
	**      kernel/ksyms.c 
	**
	** As a consequence, using this driver as KLM is not possible
	** and any access of the structure kernel_stat via the 
	** dedicated macros kstat_cpu(i).cpustat.xxx is to be avoided.
	**
	** The kstat-information might be added again in future 
	** versions of the 2.5.xx kernel, but for the time being, 
	** number of interrupts will serve as indication how much 
	** load we currently have... 
	**
	** for (NbrCpu = 0; NbrCpu < num_online_cpus(); NbrCpu++) {
	**	UserTime   = UserTime   + kstat_cpu(NbrCpu).cpustat.user;
	**	NiceTime   = NiceTime   + kstat_cpu(NbrCpu).cpustat.nice;
	**	SystemTime = SystemTime + kstat_cpu(NbrCpu).cpustat.system;
	** }
	*/
	SK_U64 ThresholdInts  = 0;
	SK_U64 IsrCallsPerSec = 0;

	ThresholdInts  = ((M_DIMINFO.MaxModIntsPerSec *
			   C_INT_MOD_ENABLE_PERCENTAGE) + 100);
	IsrCallsPerSec = GetIsrCalls(pAC);
	if (IsrCallsPerSec >= ThresholdInts) {
	    /*
	    ** We do not know how much the real CPU-load is!
	    ** Return 80% as a default in order to activate DIM
	    */
	    SystemLoad = 80;
	    return (SystemLoad);  
	} 

	UsedTime  = UserTime + NiceTime + SystemTime;

	IdleTime  = jif * num_online_cpus() - UsedTime;
	TotalTime = UsedTime + IdleTime;

	SystemLoad = ( 100 * (UsedTime  - M_DIMINFO.PrevUsedTime) ) /
						(TotalTime - M_DIMINFO.PrevTotalTime);

	if (M_DIMINFO.DisplayStats) {
		printk("Current system load is: %u\n", SystemLoad);
	}

	M_DIMINFO.PrevTotalTime = TotalTime;
	M_DIMINFO.PrevUsedTime  = UsedTime;

	return (SystemLoad);
}

/*******************************************************************************
** Function     : GetIsrCalls
** Description  : Depending on the selected moderation mask, this function will
**                return the number of interrupts handled in the previous time-
**                frame. This evaluated number is based on the current number 
**                of interrupts stored in PNMI-context and the previous stored 
**                interrupts.
** Programmer   : Ralph Roesler
** Last Modified: 23-mar-03
** Returns      : int:   the number of interrupts being executed in the last
**                       timeframe
** Notes        : It makes only sense to call this function, when dynamic 
**                interrupt moderation is applied
*******************************************************************************/