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1.1 root 1: From [email protected] Sun Mar 15 20:01:06 1992 2: Received: from klaava.Helsinki.FI by kruuna.helsinki.fi with SMTP id AA04345 3: (5.65c/IDA-1.4.4 for <[email protected]>); Sun, 15 Mar 1992 20:00:45 +0200 4: Received: from csi.UOttawa.CA (csi0.csi.uottawa.ca) by klaava.Helsinki.FI (4.1/SMI-4.1) 5: id AA21712; Sun, 15 Mar 92 20:00:40 +0200 6: Received: by csi.UOttawa.CA id AA00608 7: (5.65+/IDA-1.3.5 for [email protected]); Sun, 15 Mar 92 12:57:47 -0500 8: From: Keith White <[email protected]> 9: Message-Id: <[email protected]> 10: Subject: reset-floppy fixed, double your disk speed (linux 0.95) 11: To: [email protected] (Linus Torvalds) 12: Date: Sun, 15 Mar 92 12:57:46 EST 13: X-Mailer: ELM [version 2.3 PL11] 14: Status: OR 15: 16: A couple of things. 17: 18: 1) I must be one of those lucky few who's been able to use linux0.95. 19: However I was surprised to see that hard disk speed was slower. This 20: was until I remembered that I had patched fs/block_dev.c and 21: include/asm/segment.h to support block moves to and from the fs 22: segment. These patches (very minimal it must be admitted) give a 23: reasonable increase in speed for 'fsck': 24: original: 42.62 elapsed 25: patched: 22.06 elapsed 26: These patches have no effect on sequential disk access (dd if=/dev/hda 27: ...) since most time is spent waiting for those small 2 sector 28: transfers anyway. The patches are included below. 29: 30: 2) I don't run DOS so a floppy disk format program is sort of 31: essential. Lawrence Foard's (sp?) formatting routines have a few 32: problems (nits). 33: a) The inter-sector gap should be larger for a format than it 34: is for a read or write. 35: b) An interleave is not required (at least on my machine, a 36: bottom of the line 386SX-16). 37: 38: 3) I seem to have fixed the dreaded "reset-floppy called" problem -- 39: at least it works for me. The posted fix does not work in my case. 40: I'd send you these patches as well, but I only have diffs that include 41: all the mods I did for the floppy format stuff. The key point (I 42: think) was to only reset twice during an error loop. If a track was 43: bad, the recalibrate would fail and call reset which would call 44: recalibrate ... If you're interested, I could try to separate the 45: formatting stuff and all my debugging "printks" from the reset fix 46: stuff and send the diffs. 47: 48: ...keith ([email protected]) 49: 50: ---cut here--- 51: *** 1.1 1992/03/14 16:33:21 52: --- include/asm/segment.h 1992/03/15 17:10:14 53: *************** 54: *** 63,65 **** 55: --- 63,109 ---- 56: __asm__("mov %0,%%fs"::"r" ((unsigned short) val)); 57: } 58: 59: + /* 60: + * these routines are added to use the movs instruction with data 61: + * in the fs segment. No optimizations are done with regards to using 62: + * movsw or movsd 63: + * 64: + * [email protected] 65: + */ 66: + 67: + #define memcpy_fromfs(dest,src,n) __asm__ (\ 68: + "mov %%fs,%%ax; movl %%ax,%%ds\n\ 69: + cld; rep; movsb\n\ 70: + mov %%es,%%ax; mov %%ax,%%ds" \ 71: + ::"D" ((long)(dest)), "S" ((long)(src)), "c" ((long) (n)) \ 72: + :"di", "si", "cx", "ax"); 73: + #define memcpy_fromfs_w(dest,src,n) __asm__ (\ 74: + "mov %%fs,%%ax; movl %%ax,%%ds\n\ 75: + cld; rep; movsw\n\ 76: + mov %%es,%%ax; mov %%ax,%%ds" \ 77: + ::"D" ((long)(dest)), "S" ((long)(src)), "c" ((long) (n)) \ 78: + :"di", "si", "cx", "ax"); 79: + #define memcpy_fromfs_l(dest,src,n) __asm__ (\ 80: + "mov %%fs,%%ax; movl %%ax,%%ds\n\ 81: + cld; rep; movsl\n\ 82: + mov %%es,%%ax; mov %%ax,%%ds" \ 83: + ::"D" ((long)(dest)), "S" ((long)(src)), "c" ((long) (n)) \ 84: + :"di", "si", "cx", "ax"); 85: + #define memcpy_tofs(dest,src,n) __asm__ (\ 86: + "mov %%fs,%%ax; mov %%ax,%%es\n\ 87: + cld; rep; movsb\n\ 88: + mov %%ds,%%ax; mov %%ax,%%es" \ 89: + ::"D" ((long)(dest)), "S" ((long)(src)), "c" ((long) (n)) \ 90: + :"di", "si", "cx", "ax"); 91: + #define memcpy_tofs_w(dest,src,n) __asm__ (\ 92: + "mov %%fs,%%ax; mov %%ax,%%es\n\ 93: + cld; rep; movsw\n\ 94: + mov %%ds,%%ax; mov %%ax,%%es" \ 95: + ::"D" ((long)(dest)), "S" ((long)(src)), "c" ((long) (n)) \ 96: + :"di", "si", "cx", "ax"); 97: + #define memcpy_tofs_l(dest,src,n) __asm__ (\ 98: + "mov %%fs,%%ax; mov %%ax,%%es\n\ 99: + cld; rep; movsl\n\ 100: + mov %%ds,%%ax; mov %%ax,%%es"\ 101: + ::"D" ((long)(dest)), "S" ((long)(src)), "c" ((long) (n)) \ 102: + :"di", "si", "cx", "ax"); 103: *** 1.1 1992/03/14 16:37:10 104: --- fs/block_dev.c 1992/03/14 16:38:26 105: *************** 106: *** 47,54 **** 107: --- 47,64 ---- 108: filp->f_pos += chars; 109: written += chars; 110: count -= chars; 111: + #ifdef notdef 112: while (chars-->0) 113: *(p++) = get_fs_byte(buf++); 114: + #else 115: + if ((chars&1) || ((long)p&1) || ((long)buf&1)) { 116: + memcpy_fromfs(p, buf, chars); 117: + } 118: + else { 119: + memcpy_fromfs_w(p, buf, chars>>1); 120: + } 121: + p += chars; buf += chars; chars = 0; 122: + #endif 123: bh->b_dirt = 1; 124: brelse(bh); 125: } 126: *************** 127: *** 85,92 **** 128: --- 95,112 ---- 129: filp->f_pos += chars; 130: read += chars; 131: count -= chars; 132: + #ifdef notdef 133: while (chars-->0) 134: put_fs_byte(*(p++),buf++); 135: + #else 136: + if ((chars&1) || ((long)buf&1) || ((long)p&1)) { 137: + memcpy_tofs(buf, p, chars); 138: + } 139: + else { 140: + memcpy_tofs_w(buf, p, chars>>1); 141: + } 142: + p += chars; buf += chars; chars = 0; 143: + #endif 144: brelse(bh); 145: } 146: return read; 147: ---cut here--- 148: 149: -- 150: BITNET: [email protected] (being phased out) 151: UUCP: {...,nrcaer,cunews}!uotcsi2!kwhite 152: INTERNET: [email protected] 153:
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