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Nikolay Shirokovskiy 489c81c00c parallels: add block device statistics to driver
Statistics provided through PCS SDK. As we have only async interface in SDK we
need to be subscribed to statistics in order to get it. Trivial solution on
every stat request to subscribe, wait event and then unsubscribe will lead to
significant delays in case of a number of successive requests, as the event
will be delivered on next PCS server notify cycle. On the other hand we don't
want to keep unnesessary subscribtion. So we take an hibrid solution to
subcsribe on first request and then keep a subscription while requests are
active. We populate cache of statistics on subscribtion events and use this
cache to serve libvirts requests.

 * Cache details.
Cache is just handle to last arrived event, we call this cache
as if this handle is valid it is used to serve synchronous
statistics requests. We use number of successive events count
to detect that user lost interest to statistics. We reset this
count to 0 on every request. If more than PARALLELS_STATISTICS_DROP_COUNT
successive events arrive we unsubscribe. Special value of -1
of this counter is used to differentiate between subscribed/unsubscribed state
to protect from delayed events.

Values of PARALLELS_STATISTICS_DROP_COUNT and PARALLELS_STATISTICS_TIMEOUT are
just drop-ins, choosen without special consideration.

 * Thread safety issues
Use parallelsDomObjFromDomainRef in parallelsDomainBlockStats as
we could wait on domain lock down on stack in prlsdkGetStatsParam
and if we won't keep reference we could get dangling pointer
on return from wait.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@parallels.com>
2015-06-09 16:43:10 +03:00
.gnulib@f39477dba7 maint: update to latest gnulib 2015-06-01 13:23:18 -06:00
build-aux bracket-spacing: Add syntax-check for unnecessary curly brackets 2014-11-14 17:13:36 +01:00
daemon remote: fix odd comma operator 2015-06-04 21:44:48 -06:00
docs maint: remove incorrect apostrophes from 'its' 2015-06-04 10:01:42 +02:00
examples Apparmor: allow reading block-rbd.so 2015-04-24 10:47:42 +02:00
gnulib maint: fix date in local gnulib patch 2015-01-05 16:44:10 +00:00
include Introduce virDomainSetUserPassword API 2015-05-21 16:04:01 +02:00
m4 maint: update to latest gnulib 2015-05-26 10:53:12 -06:00
po Release of libvirt-1.2.16 2015-06-01 10:30:29 +08:00
src parallels: add block device statistics to driver 2015-06-09 16:43:10 +03:00
tests qemu: command: Support arm 32-on-64 KVM with -cpu aarch64=off 2015-06-08 17:51:06 -04:00
tools virsh: change-media: Fix behavior with --update without a source 2015-06-09 14:06:08 +02:00
.ctags maint: Make ctags work out of the box 2013-07-18 08:47:21 +02:00
.dir-locals.el build: avoid tabs that failed syntax-check 2012-09-06 09:43:46 -06:00
.gitignore maint: Ignore Vim swap files 2015-05-13 08:39:14 -06:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap maint: update .mailmap for recent contributions 2015-03-20 06:17:55 -06:00
AUTHORS.in AUTHORS: Add my email address to AUTHORS.in 2015-04-10 18:26:43 +03:00
autobuild.sh Disable libvirtd by default when building on Win32 2014-04-29 11:30:32 +01:00
autogen.sh maint: improve usage of autogen's --no-git 2015-02-06 11:35:29 -07:00
bootstrap maint: update to latest gnulib 2015-03-26 09:41:55 -06:00
bootstrap.conf Revert "bootstrap.conf: add check for flex" 2015-01-12 10:14:30 -07:00
cfg.mk Fix build --without-network 2015-05-13 15:04:41 +02:00
ChangeLog-old Fix typos in src/* 2014-04-21 16:49:08 -06:00
config-post.h build: fix build of virt-login-shell on systems with older gnutls 2013-10-22 09:41:50 -06:00
configure.ac build: silence ar warnings on rawhide 2015-06-02 11:04:58 -06:00
COPYING maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
COPYING.LESSER maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
HACKING tests: Add VIR_TEST_REGENERATE_OUTPUT 2015-04-23 17:08:48 -04:00
libvirt-lxc.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt-qemu.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.spec.in spec: fixes for recently introduced libxl conf files 2015-06-01 12:01:18 -06:00
Makefile.am examples: Introduce domtop 2014-07-18 16:39:54 +02:00
Makefile.nonreentrant maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
mingw-libvirt.spec.in Move virConnect related APIs out of libvirt.h.in 2014-10-24 17:23:51 +01:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking docs: update README-hacking 2014-05-06 16:20:24 -06:00
run.in Add PKG_CONFIG_PATH to run.in script. 2014-06-26 14:32:35 +01:00
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00

         LibVirt : simple API for virtualization

  Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.

Daniel Veillard <veillard@redhat.com>