The following commit has been merged in the master branch:
commit 9d81bf92ef791ad4644f36d3b5f7361e883134d6
Author: Stefan Fritsch <s...@sfritsch.de>
Date: Sat Feb 27 06:31:47 2010 +0100
dpkg: Use posix_fadvise on non-Linux to speed up .list files loading
When FIEMAP is not available try to use posix_fadvise() to request
the preloading of the .list files. A search with dpkg-query went
from 28 to 17 seconds, giving around 40% improvement.
Closes: #557560
Signed-off-by: Guillem Jover <guil...@debian.org>
diff --git a/configure.ac b/configure.ac
index 967f8c1..15cdfb0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -124,7 +124,8 @@ DPKG_CHECK_DECL([WCOREDUMP], [sys/wait.h])
DPKG_CHECK_COMPAT_FUNCS([getopt getopt_long obstack_free \
strnlen strerror strsignal \
scandir alphasort unsetenv])
-AC_CHECK_FUNCS([strtoul isascii bcopy memcpy lchown setsid getdtablesize])
+AC_CHECK_FUNCS([strtoul isascii bcopy memcpy lchown setsid getdtablesize \
+ posix_fadvise])
AC_DEFINE(LIBDPKG_VOLATILE_API, 1, [Acknowledge the volatility of the API.])
DPKG_COMPILER_WARNINGS
diff --git a/debian/changelog b/debian/changelog
index f498569..f4a58f0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -151,6 +151,9 @@ dpkg (1.15.6) UNRELEASED; urgency=low
* Use FIEMAP when available (on Linux based systems) to sort the .list
files loading order. With a cold cache it improves up to a 70%.
Thanks to Morten Hustveit <mor...@debian.org>.
+ * When FIEMAP is not available use posix_fadvise() to start preloading the
+ .list files before loading them. With a cold cache it improves up to 40%.
+ Thanks to Stefan Fritsch <s...@sfritsch.de>. Closes: #557560
[ Modestas Vainius ]
* Implement symbol patterns (Closes: #563752). From now on, it is possible to
diff --git a/src/filesdb.c b/src/filesdb.c
index 1ec8e93..4e6471d 100644
--- a/src/filesdb.c
+++ b/src/filesdb.c
@@ -324,6 +324,28 @@ pkg_files_optimize_load(struct pkg_array *array)
pkg_array_sort(array, pkg_sorter_by_listfile_phys_offs);
}
+#elif defined(HAVE_POSIX_FADVISE)
+static void
+pkg_files_optimize_load(struct pkg_array *array)
+{
+ int i;
+
+ /* Ask the kernel to start preloading the list files, so as to get a
+ * boost when later we actually load them. */
+ for (i = 0; i < array->n_pkgs; i++) {
+ struct pkginfo *pkg = array->pkgs[i];
+ const char *listfile;
+ int fd;
+
+ listfile = pkgadminfile(pkg, LISTFILE);
+
+ fd = open(listfile, O_RDONLY | O_NONBLOCK);
+ if (fd != -1) {
+ posix_fadvise(fd, 0, 0, POSIX_FADV_WILLNEED);
+ close(fd);
+ }
+ }
+}
#else
static void
pkg_files_optimize_load(struct pkg_array *array)
--
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