/* diskmodel (version 1.0) * Authors: John Bucy, Greg Ganger * Contributors: John Griffin, Jiri Schindler, Steve Schlosser * * Copyright (c) of Carnegie Mellon University, 2001-2008. * * This software is being provided by the copyright holders under the * following license. By obtaining, using and/or copying this * software, you agree that you have read, understood, and will comply * with the following terms and conditions: * * Permission to reproduce, use, and prepare derivative works of this * software is granted provided the copyright and "No Warranty" * statements are included with all reproductions and derivative works * and associated documentation. This software may also be * redistributed without charge provided that the copyright and "No * Warranty" statements are included in all redistributions. * * NO WARRANTY. THIS SOFTWARE IS FURNISHED ON AN "AS IS" BASIS. * CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY KIND, EITHER * EXPRESSED OR IMPLIED AS TO THE MATTER INCLUDING, BUT NOT LIMITED * TO: WARRANTY OF FITNESS FOR PURPOSE OR MERCHANTABILITY, EXCLUSIVITY * OF RESULTS OR RESULTS OBTAINED FROM USE OF THIS SOFTWARE. CARNEGIE * MELLON UNIVERSITY DOES NOT MAKE ANY WARRANTY OF ANY KIND WITH * RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT * INFRINGEMENT.  COPYRIGHT HOLDERS WILL BEAR NO LIABILITY FOR ANY USE * OF THIS SOFTWARE OR DOCUMENTATION.   *//* * DiskSim Storage Subsystem Simulation Environment (Version 2.0) * Revision Authors: Greg Ganger * Contributors: Ross Cohen, John Griffin, Steve Schlosser * * Copyright (c) of Carnegie Mellon University, 1999. * * Permission to reproduce, use, and prepare derivative works of * this software for internal use is granted provided the copyright * and "No Warranty" statements are included with all reproductions * and derivative works. This software may also be redistributed * without charge provided that the copyright and "No Warranty" * statements are included in all redistributions. * * NO WARRANTY. THIS SOFTWARE IS FURNISHED ON AN "AS IS" BASIS. * CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY KIND, EITHER * EXPRESSED OR IMPLIED AS TO THE MATTER INCLUDING, BUT NOT LIMITED * TO: WARRANTY OF FITNESS FOR PURPOSE OR MERCHANTABILITY, EXCLUSIVITY * OF RESULTS OR RESULTS OBTAINED FROM USE OF THIS SOFTWARE. CARNEGIE * MELLON UNIVERSITY DOES NOT MAKE ANY WARRANTY OF ANY KIND WITH RESPECT * TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT INFRINGEMENT. *//* * DiskSim Storage Subsystem Simulation Environment * Authors: Greg Ganger, Bruce Worthington, Yale Patt * * Copyright (C) 1993, 1995, 1997 The Regents of the University of Michigan  * * This software is being provided by the copyright holders under the * following license. By obtaining, using and/or copying this software, * you agree that you have read, understood, and will comply with the * following terms and conditions: * * Permission to use, copy, modify, distribute, and sell this software * and its documentation for any purpose and without fee or royalty is * hereby granted, provided that the full text of this NOTICE appears on * ALL copies of the software and documentation or portions thereof, * including modifications, that you make. * * THIS SOFTWARE IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE, * BUT NOT LIMITATION, COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR * WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR * THAT THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY * THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS. COPYRIGHT * HOLDERS WILL BEAR NO LIABILITY FOR ANY USE OF THIS SOFTWARE OR * DOCUMENTATION. * *  This software is provided AS IS, WITHOUT REPRESENTATION FROM THE * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER * EXPRESSED OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE REGENTS * OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE FOR ANY DAMAGES, * INCLUDING SPECIAL , INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, * WITH RESPECT TO ANY CLAIM ARISING OUT OF OR IN CONNECTION WITH THE * USE OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN IF IT HAS * BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH DAMAGES * * The names and trademarks of copyright holders or authors may NOT be * used in advertising or publicity pertaining to the software without * specific, written prior permission. Title to copyright in this software * and any associated documentation will at all times remain with copyright * holders. */#include "mech_g1.h"#include "mech_g1_private.h"// g1 seektime computation functionsdm_time_t dm_mech_g1_seek_const(struct dm_disk_if *d,		      struct dm_mech_state *begin,		      struct dm_mech_state *end,		      int rw){  struct dm_mech_g1 *m = (struct dm_mech_g1 *)d->mech;  ddbg_assert(m->seektype == SEEK_CONST);  return m->seektime;}dm_time_t dm_mech_g1_seek_3pt_curve(struct dm_disk_if *d,			  struct dm_mech_state *begin,			  struct dm_mech_state *end,			  int rw){  dm_time_t result;  int cyls;  struct dm_mech_g1 *m = (struct dm_mech_g1 *)d->mech;    cyls = abs(end->cyl - begin->cyl);  if (cyls == 0) {    result = 0;  }   else {    result = m->seekone;    result += m->seekavg * (cyls - 1);    result += m->seekfull * sqrt32(cyls - 1);  }  return result;}dm_time_t dm_mech_g1_seek_3pt_line(struct dm_disk_if *d,			 struct dm_mech_state *begin,			 struct dm_mech_state *end,			 int rw){  int mult;  int numcyls;  int cyls;  struct dm_mech_g1 *m = (struct dm_mech_g1 *)d->mech;  dm_time_t result;  cyls = abs(end->cyl - begin->cyl);  numcyls = cyls;  if(cyls == 1) {    result = m->seekone;  }   else if(cyls == 0) {    result = 0;  }   else if(cyls <= (numcyls / 3)) {    // MATH    mult = (3*(cyls-1) / numcyls);    result = m->seekone;    result += mult * (m->seekavg - result);  }   else {    // MATH    mult = ((3*cyls - numcyls) / (2*numcyls));    result = m->seekavg;    result += mult * (m->seekfull - result);  }  return result;}// the hpl stuff has fp math in it and I don't have time to fix// it now#ifndef _DISKMODEL_FREEBSD/* seek equation described in Ruemmler and Wilkes's IEEE Computer * article (March 1994).  Uses six parameters: a division point * (between the root based equation and the linear equation), a * constant and mulitplier for the square root of the distance, a * constant and multiplier for the distance (linear part of curve) and * a value for single cylinder seeks.   */dm_time_t dm_mech_g1_seek_hpl(struct dm_disk_if *d,		    struct dm_mech_state *begin,		    struct dm_mech_state *end,		    int rw){  dm_time_t *hpseek;  int dist;  dm_time_t result;  struct dm_mech_g1 *m = (struct dm_mech_g1 *)d->mech;  hpseek = m->hpseek;  dist = abs(end->cyl - begin->cyl);  if (dist == 0) {    result = 0.0;  }  else if((dist == 1) && (hpseek[5] != -1)) {    result = m->seekone;  }   else if(dist < hpseek[0]) {    // XXX: math voodoo    result = ((sqrt64((uint64_t)dist << 32) * hpseek[2]) >> 16) + hpseek[1];  }   else {    result = (hpseek[4] * (double) dist) + hpseek[3];  }  return result;}/* An extended version of the equation described above, wherein the * first ten seek distances are explicitly provided, since seek time * curves tend to be choppy in this region.  (See UM TR CSE-TR-194-94)  */dm_time_t dm_mech_g1_seek_1st10_plus_hpl(struct dm_disk_if *d, 			       struct dm_mech_state *begin,			       struct dm_mech_state *end,			       int rw){  dm_time_t *hpseek;  dm_time_t result;  int dist = abs(end->cyl - begin->cyl);  struct dm_mech_g1 *m = (struct dm_mech_g1 *)d->mech;    hpseek = m->hpseek;    if(dist == 0) {    result = 0;  }   else if (dist <= 10) {    result = m->first10seeks[(dist - 1)];  }   else if (dist < m->hpseek_v1) {    // XXX: math voodoo    result = ((sqrt64((uint64_t)dist << 32) * hpseek[2]) >> 16) + hpseek[1];  }   else {    result = (hpseek[4] * dist) + hpseek[3];  }  if(begin->head != end->head) {    double headsw;    headsw = d->mech->dm_headswitch_time(d, begin->head, end->head);    if(headsw > result) {      result = headsw;    }  }  return result;}#else  dm_time_t dm_mech_g1_seek_hpl(struct dm_disk_if *d,		    struct dm_mech_state *begin,		    struct dm_mech_state *end,		    int rw){  ddbg_assert2(0, "seek_hpl currently unavailable for kernel");  return 0;}dm_time_t dm_mech_g1_seek_1st10_plus_hpl(struct dm_disk_if *d, 			       struct dm_mech_state *begin,			       struct dm_mech_state *end,			       int rw){  ddbg_assert2(0, "seek_1st10_plus_hpl currently unavailable for kernel");  return 0;}#endif // _DISKMODEL_FREEBSDdm_time_t dm_mech_g1_seek_extracted(struct dm_disk_if *d,			  struct dm_mech_state *begin,			  struct dm_mech_state *end,			  int rw)			      {  dm_time_t result = 0;  int i;  int dist = abs(end->cyl - begin->cyl);     struct dm_mech_g1 *m = (struct dm_mech_g1 *)d->mech;  dm_time_t t1,t2;  int d1, d2;   if(dist) {     // linear search of extracted seek curve     // might want to do something faster     // binsearch -- d_i <= d < d_{i+1}     for(i = 0; i < m->xseekcnt; i++) {       if(dist == m->xseekdists[i]) {	 result = m->xseektimes[i];	 break;       }        // The computation here will also do linear extrapolation if       // we're past the end.       else if (dist <= m->xseekdists[i]		|| (i == m->xseekcnt-1))       {	 t1 = m->xseektimes[i-1];	 t2 = m->xseektimes[i];	 d1 = m->xseekdists[i-1];	 d2 = m->xseekdists[i];	 	 // didn't find it exactly; do some interpolation	 /*  	   int ddiff =  */	 /*  	     (dist - m->xseekdists[(i-1)]) /  */	 /*  	     (m->xseekdists[i] - m->xseekdists[(i-1)]); */	 // this sounds perverse but in e.g. the atlas10k model	 // 10,     1.53100	 // 12,     1.51500	 // so its possible to get a negative answer here!	 result = m->xseektimes[(i-1)];	 // this is so convoluted because dm_time_t is unsigned...	 if(t1 > t2) {	   // result -= ddiff * (t1 - t2);	   result -= (dist - d1) * (t1 - t2) / (d2 - d1);	 }	 else {	   //	     result += ddiff * (t2 - t1);	   result += (dist - d1) * (t2 - t1) / (d2 - d1);	 }	 break;       }     }   }   return result;}// these must line up with disk_seek_t dm_mech_g1_seekfn dm_mech_g1_seekfns[] = {  dm_mech_g1_seek_const,  dm_mech_g1_seek_3pt_line,  dm_mech_g1_seek_3pt_curve,  dm_mech_g1_seek_hpl,  dm_mech_g1_seek_1st10_plus_hpl,  dm_mech_g1_seek_extracted};