similar to: [PATCH 1/3] Add fadvise interface wrapper

Warning for kernel folks: I'm not much of an mm person; let me know if I got anything horribly wrong. Many folks use rsync in their nightly backup jobs. In these applications, speed is of minimal concern and should be sacrificed in order to minimize the effect of rsync on the rest of the machine. When rsync is working on a large directory it can quickly fill the page cache with written data,

Use the FADV_DONTNEED fadvise hint after finishing reading an origin fd in the sender. --- sender.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/sender.c b/sender.c index 59dae7d..a934bfe 100644 --- a/sender.c +++ b/sender.c @@ -338,6 +338,12 @@ void send_files(int f_in, int f_out) if (do_progress) end_progress(st.st_size); + if

Use the FADV_DONTNEED fadvise hint after finishing writing to a destinataion fd in the receiver. --- receiver.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/receiver.c b/receiver.c index 39c5e49..33b21fb 100644 --- a/receiver.c +++ b/receiver.c @@ -721,6 +721,12 @@ int recv_files(int f_in, char *local_name) recv_ok = receive_data(f_in, fnamecmp, fd1,

While going through an old todo list I found that these patches had fallen by the way-side. About a year ago I initiated a discussion[1] with the Linux kernel folks regarding the lack of any useable fadvise support on the kernel side. As a result, I was observing extremely poor performance on my server after backup as executable pages were being swapped out in favor of data waiting to be flushed

I've recently been trying to track down the root cause of my server's persistent issue of thrashing horribly after being left inactive. It seems that the issue is likely my nightly backup schedule (using rsync) which traverses my entire 50GB home directory. I was surprised to find that rsync does not use fadvise to notify the kernel of its use-once data usage pattern. It looks like a

On Fri, Aug 7, 2020 at 5:07 PM Richard W.M. Jones <rjones@redhat.com> wrote: > > On Fri, Aug 07, 2020 at 04:43:12PM +0300, Nir Soffer wrote: > > On Fri, Aug 7, 2020, 16:16 Richard W.M. Jones <rjones@redhat.com> wrote: > > > I'm not sure if or even how we could ever do a robust O_DIRECT > > > > > > > We can let the plugin an filter deal with

On Fri, Aug 7, 2020, 16:16 Richard W.M. Jones <rjones@redhat.com> wrote: > On Fri, Aug 07, 2020 at 07:53:13AM -0500, Eric Blake wrote: > > >$ free -m; time ./nbdkit file /var/tmp/random fadvise=sequential > cache=none --run 'qemu-img convert -n -p -m 16 -W $nbd >

On 8/7/20 6:31 AM, Richard W.M. Jones wrote: > You can use these flags as described in the manual page to optimize > access patterns, and to get better behaviour with the page cache in > some scenarios. And if you guess wrong, it is only a performance penalty, not a correctness issue. > > For my testing I used the cachedel and cachestats utilities written by > Julius Plenz

On Fri, Aug 07, 2020 at 04:43:12PM +0300, Nir Soffer wrote: > On Fri, Aug 7, 2020, 16:16 Richard W.M. Jones <rjones@redhat.com> wrote: > > I'm not sure if or even how we could ever do a robust O_DIRECT > > > > We can let the plugin an filter deal with that. The simplest solution is to > drop it on the user and require aligned requests. I mean this is very error

On Fri, Aug 11, 2017 at 05:50:47PM +0530, Ravishankar N wrote: > > > On 08/11/2017 04:51 PM, Niels de Vos wrote: > > On Fri, Aug 11, 2017 at 12:47:47AM -0400, Raghavendra Gowdappa wrote: > > > Hi all, > > > > > > In a conversation between me, Milind and Csaba, Milind pointed out > > > fadvise(2) [1] and its potential benefits to Glusterfs'

You can use these flags as described in the manual page to optimize access patterns, and to get better behaviour with the page cache in some scenarios. For my testing I used the cachedel and cachestats utilities written by Julius Plenz (https://github.com/Feh/nocache). I started with a 32 GB file of random data on a machine with about 32 GB of RAM. At the beginning of the test I evicted the

On Fri, Aug 07, 2020 at 07:53:13AM -0500, Eric Blake wrote: > >$ free -m; time ./nbdkit file /var/tmp/random fadvise=sequential cache=none --run 'qemu-img convert -n -p -m 16 -W $nbd "json:{\"file.driver\":\"null-co\",\"file.size\":\"1E\"}"' ; free -m ; cachestats /var/tmp/random > > Hmm - the -W actually says that qemu-img is

On 08/11/2017 04:51 PM, Niels de Vos wrote: > On Fri, Aug 11, 2017 at 12:47:47AM -0400, Raghavendra Gowdappa wrote: >> Hi all, >> >> In a conversation between me, Milind and Csaba, Milind pointed out >> fadvise(2) [1] and its potential benefits to Glusterfs' caching >> translators like read-ahead etc. After discussing about it, we agreed >> that our

On Fri, Aug 11, 2017 at 12:47:47AM -0400, Raghavendra Gowdappa wrote: > Hi all, > > In a conversation between me, Milind and Csaba, Milind pointed out > fadvise(2) [1] and its potential benefits to Glusterfs' caching > translators like read-ahead etc. After discussing about it, we agreed > that our performance translators can leverage the hints to provide > better

On Wed, Oct 23, 2013 at 03:38:30AM +0100, Pádraig Brady wrote: [...] By the way, Eric Sandeen solved the problem. It's a genuine misfeature in ext4 called auto_da_alloc which causes a flush on close if the file has been truncated (ftruncate or O_TRUNC) and the file size is zero bytes. I added these patches which work around the issue:

On 10/22/2013 05:56 PM, Gabriel de Perthuis wrote: > --- > pxzcat.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/pxzcat.c b/pxzcat.c > index 4ab8689..9bcdc36 100644 > --- a/pxzcat.c > +++ b/pxzcat.c > @@ -29,10 +29,11 @@ > * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT > * OF THE USE OF THIS SOFTWARE,

On Sat, Aug 19, 2017 at 4:27 PM, Csaba Henk <chenk at redhat.com> wrote: > Hi Niels, > > On Fri, Aug 11, 2017 at 2:33 PM, Niels de Vos <ndevos at redhat.com> wrote: > > On Fri, Aug 11, 2017 at 05:50:47PM +0530, Ravishankar N wrote: > [...] > >> To me it looks like fadvise (mm/fadvise.c) affects only the linux page > cache > >> behavior and is

Hi Niels, On Fri, Aug 11, 2017 at 2:33 PM, Niels de Vos <ndevos at redhat.com> wrote: > On Fri, Aug 11, 2017 at 05:50:47PM +0530, Ravishankar N wrote: [...] >> To me it looks like fadvise (mm/fadvise.c) affects only the linux page cache >> behavior and is decoupled from the filesystem itself. What this means for >> fuse is that the 'advise' is only to the

Hi List, I have updated my rsync fadvise patch which stops rsync from ousting all your other data from cache when running large jobs. I have also written an article about the whole issue. http://insights.oetiker.ch/linux/fadvise.html cheers tobi -- Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten http://it.oetiker.ch tobi@oetiker.ch ++41 62 213 9902

Hi all, In a conversation between me, Milind and Csaba, Milind pointed out fadvise(2) [1] and its potential benefits to Glusterfs' caching translators like read-ahead etc. After discussing about it, we agreed that our performance translators can leverage the hints to provide better performance. Now the question is how commonly applications actually provide hints? Is it something that is used