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Jitendra Kolhe 1e356fc14b mem-prealloc: reduce large guest start-up and migration time.
Using "-mem-prealloc" option for a large guest leads to higher guest
start-up and migration time. This is because with "-mem-prealloc" option
qemu tries to map every guest page (create address translations), and
make sure the pages are available during runtime. virsh/libvirt by
default, seems to use "-mem-prealloc" option in case the guest is
configured to use huge pages. The patch tries to map all guest pages
simultaneously by spawning multiple threads. Currently limiting the
change to QEMU library functions on POSIX compliant host only, as we are
not sure if the problem exists on win32. Below are some stats with
"-mem-prealloc" option for guest configured to use huge pages.

------------------------------------------------------------------------
Idle Guest      | Start-up time | Migration time
------------------------------------------------------------------------
Guest stats with 2M HugePage usage - single threaded (existing code)
------------------------------------------------------------------------
64 Core - 4TB   | 54m11.796s    | 75m43.843s
64 Core - 1TB   | 8m56.576s     | 14m29.049s
64 Core - 256GB | 2m11.245s     | 3m26.598s
------------------------------------------------------------------------
Guest stats with 2M HugePage usage - map guest pages using 8 threads
------------------------------------------------------------------------
64 Core - 4TB   | 5m1.027s      | 34m10.565s
64 Core - 1TB   | 1m10.366s     | 8m28.188s
64 Core - 256GB | 0m19.040s     | 2m10.148s
-----------------------------------------------------------------------
Guest stats with 2M HugePage usage - map guest pages using 16 threads
-----------------------------------------------------------------------
64 Core - 4TB   | 1m58.970s     | 31m43.400s
64 Core - 1TB   | 0m39.885s     | 7m55.289s
64 Core - 256GB | 0m11.960s     | 2m0.135s
-----------------------------------------------------------------------

Changed in v2:
 - modify number of memset threads spawned to min(smp_cpus, 16).
 - removed 64GB memory restriction for spawning memset threads.

Changed in v3:
 - limit number of threads spawned based on
   min(sysconf(_SC_NPROCESSORS_ONLN), 16, smp_cpus)
 - implement memset thread specific siglongjmp in SIGBUS signal_handler.

Changed in v4
 - remove sigsetjmp/siglongjmp and SIGBUS unblock/block for main thread
   as main thread no longer touches any pages.
 - simplify code my returning memset_thread_failed status from
   touch_all_pages.

Signed-off-by: Jitendra Kolhe <jitendra.kolhe@hpe.com>
Message-Id: <1487907103-32350-1-git-send-email-jitendra.kolhe@hpe.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-03-14 13:26:36 +01:00
audio audio/sdlaudio: Allow audio playback with SDL2 2017-03-01 15:12:03 +01:00
backends mem-prealloc: reduce large guest start-up and migration time. 2017-03-14 13:26:36 +01:00
block commit: Implement .bdrv_refresh_filename 2017-03-13 12:49:33 +01:00
bsd-user translate-all: add DEBUG_LOCKING asserts 2016-10-31 10:24:45 +01:00
chardev char: remove the right fd been watched in qemu_chr_fe_set_handlers() 2017-03-06 11:46:02 +08:00
contrib contrib: add libvhost-user 2016-12-16 01:14:38 +02:00
crypto crypto: assert cipher algorithm is always valid 2017-02-27 13:37:14 +00:00
default-configs ACPI: Add Virtual Machine Generation ID support 2017-03-02 07:14:27 +02:00
disas disas/arm: Avoid unintended sign extension 2017-03-07 14:33:51 +00:00
docs docs: Add a note about mixing bootindex with "-boot order" 2017-03-14 13:26:36 +01:00
dtc@558cd81bdd dtc: Update submodule to avoid build errors 2017-03-14 12:24:29 +11:00
fpu softfloat: Use correct type in float64_to_uint64_round_to_zero() 2017-02-28 09:03:38 +03:00
fsdev throttle: factor out duplicate code 2017-02-28 10:31:46 +01:00
gdb-xml target-ppc: gdbstub: Add VSX support 2016-01-30 23:37:38 +11:00
hw pseries: Don't expose PCIe extended config space on older machine types 2017-03-14 11:54:17 +11:00
include mem-prealloc: reduce large guest start-up and migration time. 2017-03-14 13:26:36 +01:00
io io: fully parse & validate HTTP headers for websocket protocol handshake 2017-02-28 11:51:16 +00:00
libdecnumber libdecnumber: Clean up includes 2016-02-16 14:29:27 +00:00
linux-headers update Linux headers to 4.11 2017-02-28 16:18:49 +00:00
linux-user target-arm queue: 2017-02-28 14:50:17 +00:00
migration migration: Document handling of bdrv_is_allocated() errors 2017-03-13 12:49:33 +01:00
nbd nbd/server: Use real permissions for NBD exports 2017-02-28 20:47:50 +01:00
net net/filter-mirror: Follow CODING_STYLE 2017-03-06 11:46:02 +08:00
pc-bios pseries: Update SLOF firmware image 2017-03-03 17:25:32 +11:00
pixman@87eea99e44 pixman: update internal copy to pixman-0.32.6 2014-09-15 08:14:19 +02:00
po po: add missing translations in de, fr, it, zh 2016-12-14 18:47:19 +00:00
qapi block: Drop unmaintained 'archipelago' driver 2017-03-13 12:49:33 +01:00
qga qemu-ga patch queue for 2.9 2017-03-07 07:32:28 +00:00
qobject qobject: Propagate parse errors through qobject_from_json() 2017-03-07 16:07:47 +01:00
qom qapi: Drop unused non-strict qobject input visitor 2017-03-05 09:14:19 +01:00
replay replay: add record/replay for audio passthrough 2017-03-01 15:11:44 +01:00
roms pseries: Update SLOF firmware image 2017-03-03 17:25:32 +11:00
scripts qapi: Make input visitors detect unvisited list tails 2017-03-05 09:14:20 +01:00
slirp slirp: tcp_listen(): Don't try to close() an fd we never opened 2017-02-26 15:39:29 +01:00
stubs virtio, pc: fixes, features 2017-03-03 10:09:03 +00:00
target target/ppc: fix cpu_ov setting for 32-bit 2017-03-14 11:27:23 +11:00
tcg Merge branch 'icount-update' into HEAD 2017-03-03 16:39:18 +01:00
tests Block layer fixes for 2.9.0-rc1 2017-03-13 15:08:01 +00:00
trace trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00
ui vnc: fix double free issues 2017-02-27 16:22:01 +01:00
util mem-prealloc: reduce large guest start-up and migration time. 2017-03-14 13:26:36 +01:00
.dir-locals.el Add .dir-locals.el file to configure emacs coding style 2015-10-08 19:46:01 +03:00
.exrc qemu: add .exrc 2012-09-07 09:02:44 +03:00
.gitignore Makefile: Put VERSION info into version.texi rather than using -D 2017-02-20 14:11:07 +01:00
.gitmodules ppc: add skiboot firmware for the pnv platform 2016-10-28 09:36:58 +11:00
.mailmap Update mailmap 2013-09-05 09:40:31 -05:00
.shippable.yml .shippable: add s390x-cross target 2017-02-28 20:31:01 +08:00
.travis.yml .travis.yml: split VM based builds 2017-02-10 13:19:56 +00:00
accel.c clean-up: removed duplicate #includes 2016-10-28 18:17:24 +03:00
arch_init.c nios2: Add support for Nios-II R1 2017-01-24 13:10:36 -08:00
atomic_template.h tcg: Add atomic128 helpers 2016-10-26 08:29:01 -07:00
balloon.c trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00
block.c block: Refresh filename after changing backing file 2017-03-13 12:49:33 +01:00
blockdev-nbd.c trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00
blockdev.c block: Fix error handling in bdrv_replace_in_backing_chain() 2017-03-07 14:53:28 +01:00
blockjob.c blockjob: Factor out block_job_remove_all_bdrv() 2017-02-28 20:40:37 +01:00
bootdevice.c error: Remove NULL checks on error_propagate() calls 2016-06-20 16:38:13 +02:00
bt-host.c all: Clean up includes 2016-02-04 17:41:30 +00:00
bt-vhci.c all: Clean up includes 2016-02-04 17:41:30 +00:00
Changelog Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
CODING_STYLE CODING_STYLE: Mention preferred comment form 2017-02-28 09:03:38 +03:00
configure build: include sys/sysmacros.h for major() and minor() 2017-03-14 10:08:22 +00:00
COPYING
COPYING.LIB
cpu-exec-common.c tcg: remove global exit_request 2017-02-24 10:32:45 +00:00
cpu-exec.c Merge branch 'icount-update' into HEAD 2017-03-03 16:39:18 +01:00
cpus-common.c *_run_on_cpu: introduce run_on_cpu_data type 2016-10-31 15:00:25 +01:00
cpus.c cpus.c: add additional error_report when !TARGET_SUPPORT_MTTCG 2017-03-09 10:38:16 +00:00
cputlb.c cputlb: Don't assume do_unassigned_access() never returns 2017-02-28 12:08:15 +00:00
device_tree.c qemu-common: stop including qemu/bswap.h from qemu-common.h 2016-05-19 16:42:28 +02:00
device-hotplug.c blockdev: Split monitor reference from BB creation 2016-03-17 15:47:56 +01:00
disas.c Fix Thumb-1 BE32 execution and disassembly. 2017-02-07 18:29:59 +00:00
dma-helpers.c block: explicitly acquire aiocontext in bottom halves that need it 2017-02-21 11:39:39 +00:00
dump.c error: Remove NULL checks on error_propagate() calls 2016-06-20 16:38:13 +02:00
exec.c mem-prealloc: reduce large guest start-up and migration time. 2017-03-14 13:26:36 +01:00
gdbstub.c gdbstub: Fix vCont behaviour 2017-02-16 14:06:56 +01:00
HACKING HACKING: document #include order 2017-01-03 16:38:47 +00:00
hax-stub.c Plumb the HAXM-based hardware acceleration support 2017-01-19 22:07:46 +01:00
hmp-commands-info.hx qmp/hmp: add query-vm-generation-id and 'info vm-generation-id' commands 2017-03-02 07:14:27 +02:00
hmp-commands.hx COLO: Add 'x-colo-lost-heartbeat' command to trigger failover 2016-10-30 15:17:39 +05:30
hmp.c virtio, pc: fixes, features 2017-03-03 10:09:03 +00:00
hmp.h qmp/hmp: add query-vm-generation-id and 'info vm-generation-id' commands 2017-03-02 07:14:27 +02:00
ioport.c trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00
iothread.c monitor: add poll-* properties into query-iothreads result 2017-02-21 18:29:01 +00:00
kvm-all.c KVM: use KVM_CAP_IMMEDIATE_EXIT 2017-03-03 16:40:02 +01:00
kvm-stub.c KVM: move SIG_IPI handling to kvm-all.c 2017-03-03 16:40:02 +01:00
LICENSE vfio: move hw/misc/vfio.c to hw/vfio/pci.c Move vfio.h into include/hw/vfio 2014-12-19 15:24:06 -07:00
MAINTAINERS block: Drop unmaintained 'archipelago' driver 2017-03-13 12:49:33 +01:00
Makefile Makefile: Put VERSION info into version.texi rather than using -D 2017-02-20 14:11:07 +01:00
Makefile.objs block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
Makefile.target -----BEGIN PGP SIGNATURE----- 2017-02-02 16:08:28 +00:00
memory_ldst.inc.c exec: introduce memory_ldst.inc.c 2016-12-22 16:00:23 +01:00
memory_mapping.c memory: Replace skip_dump flag with "ram_device" 2016-10-31 09:53:03 -06:00
memory.c memory: show region offset and ROM/RAM type in "info mtree -f" 2017-03-03 16:40:03 +01:00
module-common.c all: Clean up includes 2016-02-04 17:41:30 +00:00
monitor.c monitor: Assert qmp_schema_json[] is sane 2017-03-07 16:07:47 +01:00
numa.c numa: Flatten simple union NumaOptions 2017-02-22 19:50:46 +01:00
os-posix.c use g_path_get_dirname instead of dirname 2016-07-17 09:59:21 +02:00
os-win32.c all: Clean up includes 2016-02-04 17:41:30 +00:00
page_cache.c coccinelle: Remove unnecessary variables for function return value 2016-06-20 16:38:13 +02:00
qapi-schema.json qapi-schema: Rename SocketAddressFlat's variant tcp to inet 2017-03-07 14:53:29 +01:00
qdev-monitor.c migrate: Introduce a 'dc->vmsd' check to avoid segfault for --only-migratable 2017-02-28 11:30:22 +00:00
qdict-test-data.txt Introduce QDict test data file 2009-09-04 09:37:34 -05:00
qemu-bridge-helper.c all: Remove unnecessary glib.h includes 2016-06-07 18:19:24 +03:00
qemu-doc.texi nios2 target support 2017-01-25 13:30:23 +00:00
qemu-ga.texi qemu-ga: Remove stray 'q' in documentation 2016-10-28 18:17:23 +03:00
qemu-img-cmds.hx qemu-img: make convert async 2017-02-28 20:40:31 +01:00
qemu-img.c commit: Add filter-node-name to block-commit 2017-02-28 20:47:50 +01:00
qemu-img.texi qemu-img: make convert async 2017-02-28 20:40:31 +01:00
qemu-io-cmds.c hmp: Request permissions in qemu-io 2017-02-28 20:47:50 +01:00
qemu-io.c qemu-io: Return non-zero exit code on failure 2017-02-12 00:47:42 +01:00
qemu-nbd.c qemu-nbd: Implement socket activation. 2017-02-16 15:30:45 +01:00
qemu-nbd.texi nbd: Add qemu-nbd -D for human-readable description 2016-11-02 09:28:55 +01:00
qemu-option-trace.texi docs: update manpage for stderr->log rename 2017-02-13 13:38:31 +00:00
qemu-options-wrapper.h hxtool: emit Texinfo headings as @subsection 2017-01-16 17:52:35 +01:00
qemu-options.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
qemu-options.hx docs: Add a note about mixing bootindex with "-boot order" 2017-03-14 13:26:36 +01:00
qemu-seccomp.c seccomp: adding getrusage to the whitelist 2016-09-21 11:26:02 +02:00
qemu-tech.texi qemu-doc: merge qemu-tech and qemu-doc 2016-10-07 10:05:54 +02:00
qemu.nsi qemu-doc: merge qemu-tech and qemu-doc 2016-10-07 10:05:54 +02:00
qemu.sasl sasl: Avoid 'Could not find keytab file' in syslog 2014-03-15 13:54:18 +04:00
qmp.c qapi: Drop unused non-strict qobject input visitor 2017-03-05 09:14:19 +01:00
qtest.c qtest: fix a memory leak 2017-03-01 00:09:28 +04:00
README README: Add linux to macOS build info 2017-01-24 23:26:52 +03:00
replication.c replication: Introduce new APIs to do replication operation 2016-09-13 11:00:56 +01:00
replication.h replication: Introduce new APIs to do replication operation 2016-09-13 11:00:56 +01:00
rules.mak rules: don't try to create missing include dirs 2017-02-07 11:52:34 +00:00
softmmu_template.h cputlb: Tidy some macros 2016-10-26 08:29:00 -07:00
spice-qemu-char.c spice-char: fix segfault in char_spice_finalize 2017-03-03 16:40:03 +01:00
tcg-runtime.c tcg: Add opcode for ctpop 2017-01-10 08:48:56 -08:00
tci.c tcg/tci: Add support for fence 2016-09-16 08:12:12 -07:00
thunk.c thunk: Rename args and fields in host-target bitmask conversion code 2016-06-07 18:19:24 +03:00
tpm.c qapi: Don't special-case simple union wrappers 2016-03-18 10:29:26 +01:00
trace-events qmp: Drop duplicated QMP command object checks 2017-03-05 09:14:19 +01:00
translate-all.c translate-all: exit cpu_restore_state early if translating 2017-03-09 10:41:43 +00:00
translate-all.h trace: Add per-vCPU tracing states for events with the 'vcpu' property 2016-07-18 18:23:12 +01:00
translate-common.c Merge branch 'icount-update' into HEAD 2017-03-03 16:39:18 +01:00
user-exec-stub.c stubs: group stubs for user-mode emulation 2017-01-16 17:52:35 +01:00
user-exec.c tcg: Merge GETPC and GETRA 2016-09-16 08:12:11 -07:00
VERSION Open 2.9 development tree 2016-12-20 16:20:16 +00:00
version.rc Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
vl.c vl/cpus: be smarter with icount and MTTCG 2017-03-09 10:38:02 +00:00
xen-common-stub.c char: rename CharDriverState Chardev 2017-01-27 18:07:59 +01:00
xen-common.c char: rename CharDriverState Chardev 2017-01-27 18:07:59 +01:00
xen-hvm-stub.c fix MSI injection on Xen 2016-02-06 20:44:10 +02:00
xen-hvm.c trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00
xen-mapcache.c trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00

         QEMU README
         ===========

QEMU is a generic and open source machine & userspace emulator and
virtualizer.

QEMU is capable of emulating a complete machine in software without any
need for hardware virtualization support. By using dynamic translation,
it achieves very good performance. QEMU can also integrate with the Xen
and KVM hypervisors to provide emulated hardware while allowing the
hypervisor to manage the CPU. With hypervisor support, QEMU can achieve
near native performance for CPUs. When QEMU emulates CPUs directly it is
capable of running operating systems made for one machine (e.g. an ARMv7
board) on a different machine (e.g. an x86_64 PC board).

QEMU is also capable of providing userspace API virtualization for Linux
and BSD kernel interfaces. This allows binaries compiled against one
architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a
different architecture ABI (e.g. the Linux x86_64 ABI). This does not
involve any hardware emulation, simply CPU and syscall emulation.

QEMU aims to fit into a variety of use cases. It can be invoked directly
by users wishing to have full control over its behaviour and settings.
It also aims to facilitate integration into higher level management
layers, by providing a stable command line interface and monitor API.
It is commonly invoked indirectly via the libvirt library when using
open source applications such as oVirt, OpenStack and virt-manager.

QEMU as a whole is released under the GNU General Public License,
version 2. For full licensing details, consult the LICENSE file.


Building
========

QEMU is multi-platform software intended to be buildable on all modern
Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
of other UNIX targets. The simple steps to build QEMU are:

  mkdir build
  cd build
  ../configure
  make

Additional information can also be found online via the QEMU website:

  http://qemu-project.org/Hosts/Linux
  http://qemu-project.org/Hosts/Mac
  http://qemu-project.org/Hosts/W32


Submitting patches
==================

The QEMU source code is maintained under the GIT version control system.

   git clone git://git.qemu-project.org/qemu.git

When submitting patches, the preferred approach is to use 'git
format-patch' and/or 'git send-email' to format & send the mail to the
qemu-devel@nongnu.org mailing list. All patches submitted must contain
a 'Signed-off-by' line from the author. Patches should follow the
guidelines set out in the HACKING and CODING_STYLE files.

Additional information on submitting patches can be found online via
the QEMU website

  http://qemu-project.org/Contribute/SubmitAPatch
  http://qemu-project.org/Contribute/TrivialPatches


Bug reporting
=============

The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs
found when running code built from QEMU git or upstream released sources
should be reported via:

  https://bugs.launchpad.net/qemu/

If using QEMU via an operating system vendor pre-built binary package, it
is preferable to report bugs to the vendor's own bug tracker first. If
the bug is also known to affect latest upstream code, it can also be
reported via launchpad.

For additional information on bug reporting consult:

  http://qemu-project.org/Contribute/ReportABug


Contact
=======

The QEMU community can be contacted in a number of ways, with the two
main methods being email and IRC

 - qemu-devel@nongnu.org
   http://lists.nongnu.org/mailman/listinfo/qemu-devel
 - #qemu on irc.oftc.net

Information on additional methods of contacting the community can be
found online via the QEMU website:

  http://qemu-project.org/Contribute/StartHere

-- End