[Libguestfs] [PATCH 2/2] builder: pxzcat: Add further posix_fadvise hints.

Setting POSIX_FADV_RANDOM makes no measurable difference, but at least it's the right thing to do. POSIX_FADV_WILLNEED makes no measurable difference either. Changing POSIX_FADV_NOREUSE on the input file descriptor to POSIX_FADV_DONTNEED slows things down by about 10%. --- builder/pxzcat-c.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/builder/pxzcat-c.c b/builder/pxzcat-c.c index 44722bc..0a1c368 100644 --- a/builder/pxzcat-c.c +++ b/builder/pxzcat-c.c @@ -215,6 +215,9 @@ pxzcat (value filenamev, value outputfilev, unsigned nr_threads) } guestfs_int_fadvise_noreuse (fd); + guestfs_int_fadvise_random (fd); + guestfs_int_fadvise_random (ofd); + guestfs_int_fadvise_willneed (ofd); /* Iterate over blocks. */ iter_blocks (idx, nr_threads, filenamev, fd, outputfilev, ofd); -- 2.7.4