Alexey Polyakov wrote:
On 9/20/06, Łukasz Mierzwa <[EMAIL PROTECTED]> wrote:
It's been proven that flushes are doing much more job then they should.
Not so long ago someone send a trace of block device io accesess during
reiser4 work and someone anylized it and said that some files or parts of
file where written over and over 200 times or so.
Wow. I should go back and read that -- I assume this is being worked on?
a few months old filesystem that had been used often just shows a week
spot in reiser4, while downloading files with azureus with only 64KB of
data per second I got disk lid on almost all the time, swithcing to
rtorrent helped as it does not seem to call fsync ( I think I disabled
fsync in azureus).
Hmm, strange. I am using Azureus, but I don't think it's fsync. I can
try rtorrent, but there are several things I like about Azureus that
nothing else seems to do yet.
But also, Azureus didn't always do this. In fact, I used it for several
months before I started having this problem.
Ah, I see, if bittorrent calls fsync often, it's no wonder that
reiser4 behaves badly. I had to preload libnosync for some of my
programs that do fsync to avoid this.
Way ahead of you. I noticed how much fsync performance sucked when
using vim, and I was sick of waiting 10 seconds every time I hit :w -- a
LOT of stuff can pile up in 2 gigs of disk buffer, and at the time,
Reiser4 fsync effectively just called sync.
I didn't know about libnosync (or it didn't exist yet, or didn't work,
I'm not entirely sure), so I was faced with either patching vim, which
had just been patched to _add_ fsync'ing, not to mention all the other
programs that might fsync too much; patching glibc (huge, I don't
update it often, and I'd have no idea where to start); or patching the
kernel.
I now keep backups, and I maintain and apply the following (STUPID,
DON'T TRY THIS AT HOME) patch to my kernel:
--- linux/fs/buffer.c 2006-08-15 20:40:36.504608696 -0500
+++ linux/fs/buffer.c.new 2006-08-15 20:42:35.877461264 -0500
@@ -366,12 +366,12 @@
asmlinkage long sys_fsync(unsigned int fd)
{
- return __do_fsync(fd, 0);
+ return 0;
}
asmlinkage long sys_fdatasync(unsigned int fd)
{
- return __do_fsync(fd, 1);
+ return 0;
}
/*
