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Don't use sscanf anymore when parsins smaps.

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That's more code but it brings a 20% speed improvement.
This commit is contained in:
Benoît Dejean
2009-05-03 16:25:31 +02:00
parent 9f051c9569
commit 62bafe804e
1 changed files with 70 additions and 1 deletions
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71
sysdeps/linux/procmap.c
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@@ -141,6 +141,68 @@ parse_smaps(glibtop_map_entry *entry, const char* line)
}
/*
sscanf is too slow
and system-monitor calls procmap for each pid every second
manual parsing is faster
error checking is weaker
*/
static gboolean
parse_line(char* line,
guint64* start, guint64* end, char flags[4], guint64* offset,
gushort* dev_major, gushort* dev_minor, guint64* inode,
char** filename)
{
/* %16llx-%16llx %4c %16llx %02hx:%02hx %llu%*[ ]%n */
char *p, *next;
p = line;
*start = strtoull(p, &p, 16);
if (G_UNLIKELY(*p != '-'))
return FALSE;
p++;
*end = strtoull(p, &p, 16);
p = next_token(p);
memcpy(flags, p, 4);
p += 4;
*offset = strtoull(p, &p, 16);
*dev_major = strtoul(p, &p, 16);
if (G_UNLIKELY(*p != ':'))
return FALSE;
p++;
*dev_minor = strtoul(p, &p, 16);
*inode = strtoull(p, &p, 10);
p = next_token(p);
*filename = p;
for ( ; *p; p++) {
if (*p == '\n') {
*p = '\0';
break;
}
}
return TRUE;
}
glibtop_map_entry *
@@ -181,7 +243,7 @@ glibtop_get_proc_map_s (glibtop *server, glibtop_proc_map *buf, pid_t pid)
{
unsigned long perm;
guint len;
int line_end;
/* int line_end; */
unsigned short dev_major, dev_minor;
guint64 start, end, offset, inode;
@@ -195,6 +257,12 @@ glibtop_get_proc_map_s (glibtop *server, glibtop_proc_map *buf, pid_t pid)
new_entry_line:
if (!parse_line(line,
&start, &end, flags, &offset,
&dev_major, &dev_minor, &inode, &filename))
continue;
/*
if (sscanf(line, PROC_MAPS_FORMAT,
&start, &end, flags, &offset,
&dev_major, &dev_minor, &inode, &line_end) != 7)
@@ -202,6 +270,7 @@ glibtop_get_proc_map_s (glibtop *server, glibtop_proc_map *buf, pid_t pid)
filename = line + line_end;
g_strstrip(filename);
*/
/* Compute access permissions. */
perm = 0;