replace fgets() with mmap() and introduce udev_lib.[hc]

PATCH In review Kay Sievers 2 participants 2 messages Mar 17, 2004 – Mar 22, 2004 Kbuild

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Kay Sievers

author

2004-03-17 21:54 UTC #0 lore raw

PATCH 1/1 replace fgets() with mmap() and introduce udev_lib.[hc]

Here we replace the various fgets() with a mmap() call for the config file reading, due to the reported performance problems with klibc.

Thanks to Patrick's testing, it makes a very small, close to nothing speed gain for libc users, but a 6 times speed increase for klibc users with a 1000 line config file.

I've created a udev_lib.[hc] for this and also moved all the generic stuff from udev.h in there and uninlined the functions.

thanks,
Kay

Makefile +5 -3

diff -Nru a/Makefile b/Makefile
@@ -201,7 +201,8 @@
 	$(PWD)/libsysfs/sysfs_utils.o	\
 	$(PWD)/libsysfs/dlist.o
 
-OBJS =	udev_config.o	\
+OBJS =	udev_lib.o	\
+	udev_config.o	\
 	udev-add.o	\
 	udev-remove.o	\
 	udevdb.o	\

@@ -211,6 +212,7 @@
 	$(TDB)
 
 HEADERS =	udev.h		\
+		udev_lib.h	\
 		namedev.h	\
 		udev_version.h	\
 		udev_dbus.h	\

@@ -279,7 +281,7 @@
 	$(STRIPCMD) $@
 
 $(INFO): $(INFO).o $(OBJS) $(HEADERS) $(LIBC)
-	$(LD) $(LDFLAGS) -o $@ $(CRT0) udevinfo.o udev_config.o udevdb.o $(SYSFS) $(TDB) $(LIB_OBJS) $(ARCH_LIB_OBJS)
+	$(LD) $(LDFLAGS) -o $@ $(CRT0) udevinfo.o udev_lib.o udev_config.o udevdb.o $(SYSFS) $(TDB) $(LIB_OBJS) $(ARCH_LIB_OBJS)
 	$(STRIPCMD) $@
 
 $(DAEMON): $(DAEMON).o udevd.h $(LIBC)

@@ -287,7 +289,7 @@
 	$(STRIPCMD) $@
 
 $(SENDER): $(SENDER).o udevd.h $(LIBC)
-	$(LD) $(LDFLAGS) -o $@ $(CRT0) udevsend.o $(LIB_OBJS) $(ARCH_LIB_OBJS)
+	$(LD) $(LDFLAGS) -o $@ $(CRT0) udevsend.o udev_lib.o $(LIB_OBJS) $(ARCH_LIB_OBJS)
 	$(STRIPCMD) $@
 
 $(STARTER): $(STARTER).o $(HEADERS) $(LIBC)

klibc_fixups.c +22 -8

diff -Nru a/klibc_fixups.c b/klibc_fixups.c
@@ -28,6 +28,7 @@
 #include <fcntl.h>
 #include <sys/types.h>
 
+#include "udev.h"
 #include "klibc_fixups.h"
 #include "logging.h"

@@ -40,22 +41,35 @@
 static unsigned long get_id_by_name(const char *uname, const char *dbfile)
 {
 	unsigned long id = -1;
-	FILE *file;
-	char buf[255];
+	char line[255];
+	char *buf;
+	size_t bufsize;
+	size_t cur;
+	size_t count;
 	char *pos;
 	char *name;
 	char *idstr;
 	char *tail;
 
-	file = fopen(dbfile, "r");
-	if (file == NULL) {
-		dbg("unable to open file '%s'", dbfile);
+	if (file_map(dbfile, &buf, &bufsize) == 0) {
+		dbg("reading '%s' as db file", dbfile);
+	} else {
+		dbg("can't open '%s' as db file", dbfile);
 		return -1;
 	}
 
+	/* loop through the whole file */
+
+	cur = 0;
 	while (1) {
-		pos = fgets(buf, sizeof(buf), file);
-		if (pos == NULL)
+		count = buf_get_line(buf, bufsize, cur);
+
+		strncpy(line, buf + cur, count);
+		line[count] = '\0';
+		pos = line;
+
+		cur += count+1;
+		if (cur > bufsize)
 			break;
 
 		/* get name */

@@ -82,7 +96,7 @@
 		}
 	}
 
-	fclose(file);
+	file_unmap(buf, bufsize);
 	return id;
 }

namedev.c +1 -0

diff -Nru a/namedev.c b/namedev.c
@@ -36,6 +36,7 @@
 #include "libsysfs/sysfs/libsysfs.h"
 #include "list.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "logging.h"
 #include "namedev.h"

namedev_parse.c +37 ~~-19~~

114 lines not on this page · raw message

udev-add.c +1 -0

diff -Nru a/udev-add.c b/udev-add.c
@@ -37,6 +37,7 @@
 
 #include "libsysfs/sysfs/libsysfs.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "udev_dbus.h"
 #include "udev_selinux.h"

udev-remove.c +1 -0

diff -Nru a/udev-remove.c b/udev-remove.c
@@ -29,6 +29,7 @@
 #include <errno.h>
 
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "udev_dbus.h"
 #include "logging.h"

udev.c +4 -2

diff -Nru a/udev.c b/udev.c
@@ -20,15 +20,17 @@
  *
  */
 
+#include <stdio.h>
+#include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
-#include <stdio.h>
-#include <errno.h>
 #include <ctype.h>
+#include <errno.h>
 #include <signal.h>
 
 #include "libsysfs/sysfs/libsysfs.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "udev_dbus.h"
 #include "logging.h"

udev.h +11 ~~-95~~

123 lines not on this page · raw message

udev_config.c +21 ~~-11~~

diff -Nru a/udev_config.c b/udev_config.c
@@ -34,6 +34,7 @@
 
 #include "libsysfs/sysfs/libsysfs.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "logging.h"
 #include "namedev.h"

@@ -131,12 +132,14 @@
 	char *temp;
 	char *variable;
 	char *value;
-	FILE *fd;
-	int lineno = 0;
+	char *buf;
+	size_t bufsize;
+	size_t cur;
+	size_t count;
+	int lineno;
 	int retval = 0;
-	
-	fd = fopen(udev_config_filename, "r");
-	if (fd != NULL) {
+
+	if (file_map(udev_config_filename, &buf, &bufsize) == 0) {
 		dbg("reading '%s' as config file", udev_config_filename);
 	} else {
 		dbg("can't open '%s' as config file", udev_config_filename);

@@ -144,13 +147,20 @@
 	}
 
 	/* loop through the whole file */
+	lineno = 0;
+	cur = 0;
 	while (1) {
-		/* get a line */
-		temp = fgets(line, sizeof(line), fd);
-		if (temp == NULL)
-			goto exit;
+		count = buf_get_line(buf, bufsize, cur);
+
+		strncpy(line, buf + cur, count);
+		line[count] = '\0';
+		temp = line;
 		lineno++;
 
+		cur += count+1;
+		if (cur > bufsize)
+			break;
+
 		dbg_parse("read '%s'", temp);
 
 		/* eat the whitespace at the beginning of the line */

@@ -182,8 +192,8 @@
 	}
 	dbg_parse("%s:%d:%Zd: error parsing '%s'", udev_config_filename,
 		  lineno, temp - line, temp);
-exit:
-	fclose(fd);
+
+	file_unmap(buf, bufsize);
 	return retval;
 }

udev_lib.c new file +111 -0

111 lines not on this page · raw message

udev_lib.h new file +78 -0

78 lines not on this page · raw message

udevd.c +1 -0

diff -Nru a/udevd.c b/udevd.c
@@ -36,6 +36,7 @@
 
 #include "list.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"

udevdb.c +4 -5

diff -Nru a/udevdb.c b/udevdb.c
@@ -1,5 +1,5 @@
 /*
- * udevdb.c
+ * udevdb.c - udev database library
  *
  * Userspace devfs
  *

@@ -21,13 +21,11 @@
  *
  */
 
-/*
- * udev database library
- */
 #define _KLIBC_HAS_ARCH_SIG_ATOMIC_T
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <stddef.h>
 #include <fcntl.h>
 #include <string.h>
 #include <sys/stat.h>

@@ -35,8 +33,9 @@
 #include <signal.h>
 
 #include "libsysfs/sysfs/libsysfs.h"
-#include "udev_version.h"
 #include "udev.h"
+#include "udev_lib.h"
+#include "udev_version.h"
 #include "logging.h"
 #include "namedev.h"
 #include "udevdb.h"

udevinfo.c +1 -0

diff -Nru a/udevinfo.c b/udevinfo.c
@@ -30,6 +30,7 @@
 #include "libsysfs/sysfs/libsysfs.h"
 #include "libsysfs/dlist.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "logging.h"
 #include "udevdb.h"

udevsend.c +1 -0

diff -Nru a/udevsend.c b/udevsend.c
@@ -36,6 +36,7 @@
 #include <linux/stddef.h>
 
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"

Greg KH

2004-03-22 22:31 UTC #1 lore raw

Quoted 9 lines · Kay Sievers

Here we replace the various fgets() with a mmap() call for the config file reading, due to the reported performance problems with klibc.
Thanks to Patrick's testing, it makes a very small, close to nothing speed gain for libc users, but a 6 times speed increase for klibc users with a 1000 line config file.
I've created a udev_lib.[hc] for this and also moved all the generic stuff from udev.h in there and uninlined the functions.

Very nice. I also fixed udevtest so that it will build properly with this change. Applied.

thanks,

greg k-h

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