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comparison lib/copy-file.c @ 12198:e8fbc5424b99

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digests, copy-file: increase the IO buffer size from 4KiB to 32KiB This results in a significant decrease in syscall overhead giving a 3% speedup to the digest utilities for example (when processing large files from cache). Storage is moved from the stack to the heap as some threaded environments for example can have small stacks. * lib/copy-file.c (copy_file_preserving): Use a 32KiB malloced buffer * modules/copy-file: Depend on xalloc * lib/md2.c: Likewise * lib/md4.c: Likewise * lib/md5.c: Likewise * lib/sha1.c: Likewise * lib/sha256.c: Likewise * lib/sha512.c: Likewise
author Pádraig Brady <P@draigBrady.com>
date Thu, 22 Oct 2009 17:36:28 +0100
parents bbbbbf4cd1c5
children e8d2c6fc33ad
comparison
equal deleted inserted replaced
12197:e45d9bb2233e 12198:e8fbc5424b99
40 #include "safe-read.h" 40 #include "safe-read.h"
41 #include "full-write.h" 41 #include "full-write.h"
42 #include "acl.h" 42 #include "acl.h"
43 #include "binary-io.h" 43 #include "binary-io.h"
44 #include "gettext.h" 44 #include "gettext.h"
45 #include "xalloc.h"
45 46
46 #define _(str) gettext (str) 47 #define _(str) gettext (str)
47 48
48 /* The results of open() in this file are not used with fchdir, 49 /* The results of open() in this file are not used with fchdir,
49 therefore save some unnecessary work in fchdir.c. */ 50 therefore save some unnecessary work in fchdir.c. */
50 #undef open 51 #undef open
51 #undef close 52 #undef close
52 53
54 enum { IO_SIZE = 32 * 1024 };
53 55
54 void 56 void
55 copy_file_preserving (const char *src_filename, const char *dest_filename) 57 copy_file_preserving (const char *src_filename, const char *dest_filename)
56 { 58 {
57 int src_fd; 59 int src_fd;
58 struct stat statbuf; 60 struct stat statbuf;
59 int mode; 61 int mode;
60 int dest_fd; 62 int dest_fd;
61 char buf[4096]; 63 char *buf = xmalloc (IO_SIZE);
62 const size_t buf_size = sizeof (buf);
63 64
64 src_fd = open (src_filename, O_RDONLY | O_BINARY); 65 src_fd = open (src_filename, O_RDONLY | O_BINARY);
65 if (src_fd < 0 || fstat (src_fd, &statbuf) < 0) 66 if (src_fd < 0 || fstat (src_fd, &statbuf) < 0)
66 error (EXIT_FAILURE, errno, _("error while opening \"%s\" for reading"), 67 error (EXIT_FAILURE, errno, _("error while opening \"%s\" for reading"),
67 src_filename); 68 src_filename);
74 dest_filename); 75 dest_filename);
75 76
76 /* Copy the file contents. */ 77 /* Copy the file contents. */
77 for (;;) 78 for (;;)
78 { 79 {
79 size_t n_read = safe_read (src_fd, buf, buf_size); 80 size_t n_read = safe_read (src_fd, buf, IO_SIZE);
80 if (n_read == SAFE_READ_ERROR) 81 if (n_read == SAFE_READ_ERROR)
81 error (EXIT_FAILURE, errno, _("error reading \"%s\""), src_filename); 82 error (EXIT_FAILURE, errno, _("error reading \"%s\""), src_filename);
82 if (n_read == 0) 83 if (n_read == 0)
83 break; 84 break;
84 85
85 if (full_write (dest_fd, buf, n_read) < n_read) 86 if (full_write (dest_fd, buf, n_read) < n_read)
86 error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename); 87 error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
87 } 88 }
89
90 free (buf);
88 91
89 #if !USE_ACL 92 #if !USE_ACL
90 if (close (dest_fd) < 0) 93 if (close (dest_fd) < 0)
91 error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename); 94 error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
92 if (close (src_fd) < 0) 95 if (close (src_fd) < 0)