search for: max_writers

On 7/4/19 1:38 PM, Thomas Weißschuh wrote: > Hi all, > > It seems GCC 9 does not put read-only zero-initialized variables into the BSS > section anymore; instead it is put into RODATA. > (See the thread at [0], especially [1]) > Thanks for the pointers. > In filter/nozero a 64M large, static, zeroed, read-only array is declared. > The new behavior of GCC puts this array

It may be useful to test whether the client's use of NBD_CMD_FLAG_NO_HOLE makes a difference; do this by adding a mode to --filter=nozero to force a non-trimming zero write. Signed-off-by: Eric Blake <eblake@redhat.com> --- filters/nozero/nbdkit-nozero-filter.pod | 19 +++++++---- filters/nozero/nozero.c | 45 ++++++++++++++++++++----- tests/test-nozero.sh

Hi all, It seems GCC 9 does not put read-only zero-initialized variables into the BSS section anymore; instead it is put into RODATA. (See the thread at [0], especially [1]) In filter/nozero a 64M large, static, zeroed, read-only array is declared. The new behavior of GCC puts this array as-is into the binary inflating the size by a factor of around 10000. (Clang 8 and older GCCs work

The nozero filter can split a large request with FUA into several smaller requests; optimize whether the FUA flag is passed on to the next layer based on whether FUA is emulated with flush (only the last write needs it) or is natively supported (every write needs it). Missed in commit df0cc21d. Signed-off-by: Eric Blake <eblake@redhat.com> --- filters/nozero/nozero.c | 17 +++++++++++++++--

The preferred implementation uses __auto_type, a GCC extension also now supported by Clang. Unfortunately OpenBSD ships with GCC 4.2.1 (from 2007!) which predates this extension by quite a few years, so we have to be able to fall back to a plain macro. --- configure.ac | 20 ++++++++++- common/include/minmax.h | 63 +++++++++++++++++++++++++++++++++++

The preferred implementation uses __auto_type, a GCC extension also now supported by Clang. Unfortunately OpenBSD ships with GCC 4.2.1 (from 2007!) which predates this extension by quite a few years, so we have to be able to fall back to a plain macro. --- configure.ac | 20 ++++++++++- common/include/minmax.h | 63 +++++++++++++++++++++++++++++++++++

Another couple things I noticed that are worth improving, but aren't strictly related to implementing fast zero support. Eric Blake (2): server: Assert sane error responses nozero: More efficient FUA handling filters/nozero/nozero.c | 17 +++++++++++-- server/filters.c | 56 +++++++++++++++++++++++++++++++++-------- server/protocol.c | 32 +++++++++++++++++------ 3 files

No need for filters to specify their model in two different ways; the callback alone is sufficient. Since all filters are in-tree, we can deal with the API/ABI change made here. Signed-off-by: Eric Blake <eblake@redhat.com> --- docs/nbdkit-filter.pod | 48 +++++++++++++++------------------ include/nbdkit-filter.h | 6 ++--- filters/cow/cow.c | 2 --

On Wed, Aug 05, 2020 at 03:40:43PM +0300, Nir Soffer wrote: > On Wed, Aug 5, 2020 at 2:58 PM Richard W.M. Jones <rjones@redhat.com> wrote: > > > > On Wed, Aug 05, 2020 at 02:39:44PM +0300, Nir Soffer wrote: > > > Can we use something like the file plugin? thread pool of workers, > > > each keeping open vddk handle, and serving requests in parallel from >

...o PARALLEL ... I'll try it out and get back to you. > I'm not sure what triggers using multiple connections in qemu-img and > how it decide how many connections should be used, but we report > the number of writers in OPTIONS: > http://ovirt.github.io/ovirt-imageio/images.html#max_writers > > There is a hard limit in vdsm, because it runs qemu-nbd with > --shared=8, so you should > not use more than 8 connections, they will just block on qemu-nbd forever. It's different for qemu NBD client and server. Eric told me on IRC a few minutes ago that qemu NBD client does...

...try it out and get back to you. > > > I'm not sure what triggers using multiple connections in qemu-img and > > how it decide how many connections should be used, but we report > > the number of writers in OPTIONS: > > http://ovirt.github.io/ovirt-imageio/images.html#max_writers > > > > There is a hard limit in vdsm, because it runs qemu-nbd with > > --shared=8, so you should > > not use more than 8 connections, they will just block on qemu-nbd forever. > > It's different for qemu NBD client and server. Eric told me on IRC a > few minu...

...imageio socket, and this is likely where the plugin spends most of the time. I'm not sure what triggers using multiple connections in qemu-img and how it decide how many connections should be used, but we report the number of writers in OPTIONS: http://ovirt.github.io/ovirt-imageio/images.html#max_writers There is a hard limit in vdsm, because it runs qemu-nbd with --shared=8, so you should not use more than 8 connections, they will just block on qemu-nbd forever. We use 4 connections by default, giving about 100% speed up compared with one connection. 2 connections give about 80% speed up. If th...

Being able to programmatically force nbdkit to be less parallel can be useful during testing. I was less sure about patch 3, but if you like it, I'm inclined to instead squash it into patch 1. This patch is written to apply after my NBD_CMD_CACHE work (since I touched the nocache filter); but can be rearranged if we think this series should go in first while that one undergoes any adjustments

Hi, We are having issues with our samba server running on CentOS 7. It's generating core dumps and dumping them in the / (root filesystem) directory in the form of core.##### where the # is a series of numbers. Snippets of log files and some troubleshooting commands are below. Hope someone can have a look and see if I should file this as a bug, as there were similar posts in the samba

v4: https://www.redhat.com/archives/libguestfs/2019-January/msg00032.html v5: - Now we set the block size at run time. I'd like to say that I was able to test this change, but unfortunately I couldn't find any easy way to create a filesystem on x86-64 with a block size > 4K. Ext4 doesn't support it at all, and XFS doesn't support block size > page size (and I

After more than a month since v2 [1], I've finally got my FUA support series polished. This is all of my outstanding patches, even though some of them were originally posted in separate threads from the original FUA post [2], [3] [1] https://www.redhat.com/archives/libguestfs/2018-January/msg00113.html [2] https://www.redhat.com/archives/libguestfs/2018-January/msg00219.html [3]

Also available here: https://github.com/rwmjones/nbdkit/tree/2020-windows-mingw-nolib After a lot of work I have made the port to Windows work without using a separate library. Instead, on Windows only, we build an "import library" (library of stubs) which resolves references to nbdkit_* functions in the main program and fixes up the plugin, basically the first technique outlined in