Hi! On Sun, 2009-11-22 at 22:35:10 +0100, Stefan Fritsch wrote: > Package: dpkg > Version: 1.15.5.2 > Severity: wishlist > Tags: patch
> By using posix_fadvise with POSIX_FADV_WILLNEED on /var/dpkg/info/*.list, the > time needed to read the database can be reduced in the case where the files > are > not yet in the buffer cache. The attached patch gives 20-30% time reduction > for > installing one small package on my system (tested with echo 3 > > /proc/sys/vm/drop_caches). I applied the patch with some modifications. Added a check in configure for posix_fadvise. And moved the code into a pkg_files_optimize_load() function that will be used whenever FIEMAP is not available, which gives better improvement. > diff -Nru dpkg-1.15.5.2/src/filesdb.c dpkg-1.15.5.2+nmu1/src/filesdb.c > --- dpkg-1.15.5.2/src/filesdb.c 2009-11-18 08:28:44.000000000 +0100 > +++ dpkg-1.15.5.2+nmu1/src/filesdb.c 2009-11-22 22:23:24.000000000 +0100 > @@ -19,6 +19,8 @@ > * along with this program. If not, see <http://www.gnu.org/licenses/>. > */ > > +#define _XOPEN_SOURCE 600 > + I didn't set this as it's taken care of by AC_USE_SYSTEM_EXTENSIONS. > #include <config.h> > #include <compat.h> > > @@ -257,14 +259,28 @@ > struct pkgiterator *it; > struct pkginfo *pkg; > struct progress progress; > + int fd; > > if (allpackagesdone) return; > if (saidread<2) { > int max = countpackages(); > > saidread=1; > - progress_init(&progress, _("(Reading database ... "), max); > + progress_init(&progress, _("(Reading database ... "), 2 * max); > + } As the time doing this is insignificant compared to the actual reading, I didn't modify the progress output. > + it = iterpkgstart(); > + while ((pkg = iterpkgnext(it)) != NULL) { > + fd = open(pkgadminfile(pkg,LISTFILE), > O_RDONLY|O_NOATIME|O_NONBLOCK|O_NOCTTY); I didn't use O_NOATIME (Linux-specific), nor O_NOCTTY (no file under admindir should be a device). > + if (fd != -1) { > + posix_fadvise(fd, 0, 0, POSIX_FADV_WILLNEED); > + close(fd); > + } > + > + if (saidread == 1) > + progress_step(&progress); > } > + iterpkgend(it); > > it= iterpkgstart(); > while ((pkg = iterpkgnext(it)) != NULL) { Thanks for the patch! regards, guillem -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
