* Re: [Qemu-devel] Fwd: [PATCH v2 00/41] postcopy live migration [not found] <4FCCA39A.1050300@hp.com> @ 2012-06-04 13:13 ` Isaku Yamahata 2012-06-04 14:27 ` Chegu Vinod 0 siblings, 1 reply; 3+ messages in thread From: Isaku Yamahata @ 2012-06-04 13:13 UTC (permalink / raw) To: Chegu Vinod; +Cc: qemu-devel, kvm On Mon, Jun 04, 2012 at 05:01:30AM -0700, Chegu Vinod wrote: > Hello Isaku Yamahata, Hi. > I just saw your patches..Would it be possible to email me a tar bundle of these > patches (makes it easier to apply the patches to a copy of the upstream qemu.git) I uploaded them to github for those who are interested in it. git://github.com/yamahata/qemu.git qemu-postcopy-june-04-2012 git://github.com/yamahata/linux-umem.git linux-umem-june-04-2012 > BTW, I am also curious if you have considered using any kind of RDMA features for > optimizing the page-faults during postcopy ? Yes, RDMA is interesting topic. Can we share your use case/concern/issues? Thus we can collaborate. You may want to see Benoit's results. As long as I know, he has not published his code yet. thanks, > Thanks > Vinod > > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 4 Jun 2012 18:57:02 +0900 > From: Isaku Yamahata<yamahata@valinux.co.jp> > To: qemu-devel@nongnu.org, kvm@vger.kernel.org > Cc: benoit.hudzia@gmail.com, aarcange@redhat.com, aliguori@us.ibm.com, > quintela@redhat.com, stefanha@gmail.com, t.hirofuchi@aist.go.jp, > dlaor@redhat.com, satoshi.itoh@aist.go.jp, mdroth@linux.vnet.ibm.com, > yoshikawa.takuya@oss.ntt.co.jp, owasserm@redhat.com, avi@redhat.com, > pbonzini@redhat.com > Subject: [Qemu-devel] [PATCH v2 00/41] postcopy live migration > Message-ID:<cover.1338802190.git.yamahata@valinux.co.jp> > > After the long time, we have v2. This is qemu part. > The linux kernel part is sent separatedly. > > Changes v1 -> v2: > - split up patches for review > - buffered file refactored > - many bug fixes > Espcially PV drivers can work with postcopy > - optimization/heuristic > > Patches > 1 - 30: refactoring exsiting code and preparation > 31 - 37: implement postcopy itself (essential part) > 38 - 41: some optimization/heuristic for postcopy > > Intro > ===== > This patch series implements postcopy live migration.[1] > As discussed at KVM forum 2011, dedicated character device is used for > distributed shared memory between migration source and destination. > Now we can discuss/benchmark/compare with precopy. I believe there are > much rooms for improvement. > > [1] http://wiki.qemu.org/Features/PostCopyLiveMigration > > > Usage > ===== > You need load umem character device on the host before starting migration. > Postcopy can be used for tcg and kvm accelarator. The implementation depend > on only linux umem character device. But the driver dependent code is split > into a file. > I tested only host page size == guest page size case, but the implementation > allows host page size != guest page size case. > > The following options are added with this patch series. > - incoming part > command line options > -postcopy [-postcopy-flags<flags>] > where flags is for changing behavior for benchmark/debugging > Currently the following flags are available > 0: default > 1: enable touching page request > > example: > qemu -postcopy -incoming tcp:0:4444 -monitor stdio -machine accel=kvm > > - outging part > options for migrate command > migrate [-p [-n] [-m]] URI [<prefault forward> [<prefault backword>]] > -p: indicate postcopy migration > -n: disable background transferring pages: This is for benchmark/debugging > -m: move background transfer of postcopy mode > <prefault forward>: The number of forward pages which is sent with on-demand > <prefault backward>: The number of backward pages which is sent with > on-demand > > example: > migrate -p -n tcp:<dest ip address>:4444 > migrate -p -n -m tcp:<dest ip address>:4444 32 0 > > > TODO > ==== > - benchmark/evaluation. Especially how async page fault affects the result. > - improve/optimization > At the moment at least what I'm aware of is > - making incoming socket non-blocking with thread > As page compression is comming, it is impractical to non-blocking read > and check if the necessary data is read. > - touching pages in incoming qemu process by fd handler seems suboptimal. > creating dedicated thread? > - outgoing handler seems suboptimal causing latency. > - consider on FUSE/CUSE possibility > - don't fork umemd, but create thread? > > basic postcopy work flow > ======================== > qemu on the destination > | > V > open(/dev/umem) > | > V > UMEM_INIT > | > V > Here we have two file descriptors to > umem device and shmem file > | > | umemd > | daemon on the destination > | > V create pipe to communicate > fork()---------------------------------------, > | | > V | > close(socket) V > close(shmem) mmap(shmem file) > | | > V V > mmap(umem device) for guest RAM close(shmem file) > | | > close(umem device) | > | | > V | > wait for ready from daemon<----pipe-----send ready message > | | > | Here the daemon takes over > send ok------------pipe---------------> the owner of the socket > | to the source > V | > entering post copy stage | > start guest execution | > | | > V V > access guest RAM read() to get faulted pages > | | > V V > page fault ------------------------------>page offset is returned > block | > V > pull page from the source > write the page contents > to the shmem. > | > V > unblock<-----------------------------write() to tell served pages > the fault handler returns the page > page fault is resolved > | > | pages can be sent > | backgroundly > | | > | V > | write() > | | > V V > The specified pages<-----pipe------------request to touch pages > are made present by | > touching guest RAM. | > | | > V V > reply-------------pipe-------------> release the cached page > | madvise(MADV_REMOVE) > | | > V V > > all the pages are pulled from the source > > | | > V V > the vma becomes anonymous<----------------UMEM_MAKE_VMA_ANONYMOUS > (note: I'm not sure if this can be implemented or not) > | | > V V > migration completes exit() > > > > > Isaku Yamahata (41): > arch_init: export sort_ram_list() and ram_save_block() > arch_init: export RAM_SAVE_xxx flags for postcopy > arch_init/ram_save: introduce constant for ram save version = 4 > arch_init: refactor host_from_stream_offset() > arch_init/ram_save_live: factor out RAM_SAVE_FLAG_MEM_SIZE case > arch_init: refactor ram_save_block() > arch_init/ram_save_live: factor out ram_save_limit > arch_init/ram_load: refactor ram_load > arch_init: introduce helper function to find ram block with id string > arch_init: simplify a bit by ram_find_block() > arch_init: factor out counting transferred bytes > arch_init: factor out setting last_block, last_offset > exec.c: factor out qemu_get_ram_ptr() > exec.c: export last_ram_offset() > savevm: export qemu_peek_buffer, qemu_peek_byte, qemu_file_skip > savevm: qemu_pending_size() to return pending buffered size > savevm, buffered_file: introduce method to drain buffer of buffered > file > QEMUFile: add qemu_file_fd() for later use > savevm/QEMUFile: drop qemu_stdio_fd > savevm/QEMUFileSocket: drop duplicated member fd > savevm: rename QEMUFileSocket to QEMUFileFD, socket_close to fd_close > savevm/QEMUFile: introduce qemu_fopen_fd > migration.c: remove redundant line in migrate_init() > migration: export migrate_fd_completed() and migrate_fd_cleanup() > migration: factor out parameters into MigrationParams > buffered_file: factor out buffer management logic > buffered_file: Introduce QEMUFileNonblock for nonblock write > buffered_file: add qemu_file to read/write to buffer in memory > umem.h: import Linux umem.h > update-linux-headers.sh: teach umem.h to update-linux-headers.sh > configure: add CONFIG_POSTCOPY option > savevm: add new section that is used by postcopy > postcopy: introduce -postcopy and -postcopy-flags option > postcopy outgoing: add -p and -n option to migrate command > postcopy: introduce helper functions for postcopy > postcopy: implement incoming part of postcopy live migration > postcopy: implement outgoing part of postcopy live migration > postcopy/outgoing: add forward, backward option to specify the size > of prefault > postcopy/outgoing: implement prefault > migrate: add -m (movebg) option to migrate command > migration/postcopy: add movebg mode > > Makefile.target | 5 + > arch_init.c | 298 ++++--- > arch_init.h | 20 + > block-migration.c | 8 +- > buffered_file.c | 322 ++++++-- > buffered_file.h | 32 + > configure | 12 + > cpu-all.h | 9 + > exec-obsolete.h | 1 + > exec.c | 87 ++- > hmp-commands.hx | 18 +- > hmp.c | 10 +- > linux-headers/linux/umem.h | 42 + > migration-exec.c | 12 +- > migration-fd.c | 25 +- > migration-postcopy-stub.c | 77 ++ > migration-postcopy.c | 1771 +++++++++++++++++++++++++++++++++++++++ > migration-tcp.c | 25 +- > migration-unix.c | 26 +- > migration.c | 97 ++- > migration.h | 47 +- > qapi-schema.json | 4 +- > qemu-common.h | 2 + > qemu-file.h | 8 +- > qemu-options.hx | 25 + > qmp-commands.hx | 4 +- > savevm.c | 177 ++++- > scripts/update-linux-headers.sh | 2 +- > sysemu.h | 4 +- > umem.c | 364 ++++++++ > umem.h | 101 +++ > vl.c | 16 +- > vmstate.h | 2 +- > 33 files changed, 3373 insertions(+), 280 deletions(-) > create mode 100644 linux-headers/linux/umem.h > create mode 100644 migration-postcopy-stub.c > create mode 100644 migration-postcopy.c > create mode 100644 umem.c > create mode 100644 umem.h > > > > > ------------------------------ > > -- yamahata ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] Fwd: [PATCH v2 00/41] postcopy live migration 2012-06-04 13:13 ` [Qemu-devel] Fwd: [PATCH v2 00/41] postcopy live migration Isaku Yamahata @ 2012-06-04 14:27 ` Chegu Vinod 2012-06-04 15:13 ` Isaku Yamahata 0 siblings, 1 reply; 3+ messages in thread From: Chegu Vinod @ 2012-06-04 14:27 UTC (permalink / raw) To: Isaku Yamahata; +Cc: qemu-devel, kvm On 6/4/2012 6:13 AM, Isaku Yamahata wrote: > On Mon, Jun 04, 2012 at 05:01:30AM -0700, Chegu Vinod wrote: >> Hello Isaku Yamahata, > Hi. > >> I just saw your patches..Would it be possible to email me a tar bundle of these >> patches (makes it easier to apply the patches to a copy of the upstream qemu.git) > I uploaded them to github for those who are interested in it. > > git://github.com/yamahata/qemu.git qemu-postcopy-june-04-2012 > git://github.com/yamahata/linux-umem.git linux-umem-june-04-2012 > Thanks for the pointer... >> BTW, I am also curious if you have considered using any kind of RDMA features for >> optimizing the page-faults during postcopy ? > Yes, RDMA is interesting topic. Can we share your use case/concern/issues? Looking at large sized guests (256GB and higher) running cpu/memory intensive enterprise workloads. The concerns are the same...i.e. having a predictable total migration time, minimal downtime/freeze-time and of course minimal service degradation to the workload(s) in the VM or the co-located VM's... How large of a guest have you tested your changes with and what kind of workloads have you used so far ? > Thus we can collaborate. > You may want to see Benoit's results. Yes. 'have already seen some of Benoit's results. Hence the question about use of RDMA techniques for post copy. > As long as I know, he has not published > his code yet. Thanks Vinod > > thanks, > >> Thanks >> Vinod >> >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Mon, 4 Jun 2012 18:57:02 +0900 >> From: Isaku Yamahata<yamahata@valinux.co.jp> >> To: qemu-devel@nongnu.org, kvm@vger.kernel.org >> Cc: benoit.hudzia@gmail.com, aarcange@redhat.com, aliguori@us.ibm.com, >> quintela@redhat.com, stefanha@gmail.com, t.hirofuchi@aist.go.jp, >> dlaor@redhat.com, satoshi.itoh@aist.go.jp, mdroth@linux.vnet.ibm.com, >> yoshikawa.takuya@oss.ntt.co.jp, owasserm@redhat.com, avi@redhat.com, >> pbonzini@redhat.com >> Subject: [Qemu-devel] [PATCH v2 00/41] postcopy live migration >> Message-ID:<cover.1338802190.git.yamahata@valinux.co.jp> >> >> After the long time, we have v2. This is qemu part. >> The linux kernel part is sent separatedly. >> >> Changes v1 -> v2: >> - split up patches for review >> - buffered file refactored >> - many bug fixes >> Espcially PV drivers can work with postcopy >> - optimization/heuristic >> >> Patches >> 1 - 30: refactoring exsiting code and preparation >> 31 - 37: implement postcopy itself (essential part) >> 38 - 41: some optimization/heuristic for postcopy >> >> Intro >> ===== >> This patch series implements postcopy live migration.[1] >> As discussed at KVM forum 2011, dedicated character device is used for >> distributed shared memory between migration source and destination. >> Now we can discuss/benchmark/compare with precopy. I believe there are >> much rooms for improvement. >> >> [1] http://wiki.qemu.org/Features/PostCopyLiveMigration >> >> >> Usage >> ===== >> You need load umem character device on the host before starting migration. >> Postcopy can be used for tcg and kvm accelarator. The implementation depend >> on only linux umem character device. But the driver dependent code is split >> into a file. >> I tested only host page size == guest page size case, but the implementation >> allows host page size != guest page size case. >> >> The following options are added with this patch series. >> - incoming part >> command line options >> -postcopy [-postcopy-flags<flags>] >> where flags is for changing behavior for benchmark/debugging >> Currently the following flags are available >> 0: default >> 1: enable touching page request >> >> example: >> qemu -postcopy -incoming tcp:0:4444 -monitor stdio -machine accel=kvm >> >> - outging part >> options for migrate command >> migrate [-p [-n] [-m]] URI [<prefault forward> [<prefault backword>]] >> -p: indicate postcopy migration >> -n: disable background transferring pages: This is for benchmark/debugging >> -m: move background transfer of postcopy mode >> <prefault forward>: The number of forward pages which is sent with on-demand >> <prefault backward>: The number of backward pages which is sent with >> on-demand >> >> example: >> migrate -p -n tcp:<dest ip address>:4444 >> migrate -p -n -m tcp:<dest ip address>:4444 32 0 >> >> >> TODO >> ==== >> - benchmark/evaluation. Especially how async page fault affects the result. >> - improve/optimization >> At the moment at least what I'm aware of is >> - making incoming socket non-blocking with thread >> As page compression is comming, it is impractical to non-blocking read >> and check if the necessary data is read. >> - touching pages in incoming qemu process by fd handler seems suboptimal. >> creating dedicated thread? >> - outgoing handler seems suboptimal causing latency. >> - consider on FUSE/CUSE possibility >> - don't fork umemd, but create thread? >> >> basic postcopy work flow >> ======================== >> qemu on the destination >> | >> V >> open(/dev/umem) >> | >> V >> UMEM_INIT >> | >> V >> Here we have two file descriptors to >> umem device and shmem file >> | >> | umemd >> | daemon on the destination >> | >> V create pipe to communicate >> fork()---------------------------------------, >> | | >> V | >> close(socket) V >> close(shmem) mmap(shmem file) >> | | >> V V >> mmap(umem device) for guest RAM close(shmem file) >> | | >> close(umem device) | >> | | >> V | >> wait for ready from daemon<----pipe-----send ready message >> | | >> | Here the daemon takes over >> send ok------------pipe---------------> the owner of the socket >> | to the source >> V | >> entering post copy stage | >> start guest execution | >> | | >> V V >> access guest RAM read() to get faulted pages >> | | >> V V >> page fault ------------------------------>page offset is returned >> block | >> V >> pull page from the source >> write the page contents >> to the shmem. >> | >> V >> unblock<-----------------------------write() to tell served pages >> the fault handler returns the page >> page fault is resolved >> | >> | pages can be sent >> | backgroundly >> | | >> | V >> | write() >> | | >> V V >> The specified pages<-----pipe------------request to touch pages >> are made present by | >> touching guest RAM. | >> | | >> V V >> reply-------------pipe-------------> release the cached page >> | madvise(MADV_REMOVE) >> | | >> V V >> >> all the pages are pulled from the source >> >> | | >> V V >> the vma becomes anonymous<----------------UMEM_MAKE_VMA_ANONYMOUS >> (note: I'm not sure if this can be implemented or not) >> | | >> V V >> migration completes exit() >> >> >> >> >> Isaku Yamahata (41): >> arch_init: export sort_ram_list() and ram_save_block() >> arch_init: export RAM_SAVE_xxx flags for postcopy >> arch_init/ram_save: introduce constant for ram save version = 4 >> arch_init: refactor host_from_stream_offset() >> arch_init/ram_save_live: factor out RAM_SAVE_FLAG_MEM_SIZE case >> arch_init: refactor ram_save_block() >> arch_init/ram_save_live: factor out ram_save_limit >> arch_init/ram_load: refactor ram_load >> arch_init: introduce helper function to find ram block with id string >> arch_init: simplify a bit by ram_find_block() >> arch_init: factor out counting transferred bytes >> arch_init: factor out setting last_block, last_offset >> exec.c: factor out qemu_get_ram_ptr() >> exec.c: export last_ram_offset() >> savevm: export qemu_peek_buffer, qemu_peek_byte, qemu_file_skip >> savevm: qemu_pending_size() to return pending buffered size >> savevm, buffered_file: introduce method to drain buffer of buffered >> file >> QEMUFile: add qemu_file_fd() for later use >> savevm/QEMUFile: drop qemu_stdio_fd >> savevm/QEMUFileSocket: drop duplicated member fd >> savevm: rename QEMUFileSocket to QEMUFileFD, socket_close to fd_close >> savevm/QEMUFile: introduce qemu_fopen_fd >> migration.c: remove redundant line in migrate_init() >> migration: export migrate_fd_completed() and migrate_fd_cleanup() >> migration: factor out parameters into MigrationParams >> buffered_file: factor out buffer management logic >> buffered_file: Introduce QEMUFileNonblock for nonblock write >> buffered_file: add qemu_file to read/write to buffer in memory >> umem.h: import Linux umem.h >> update-linux-headers.sh: teach umem.h to update-linux-headers.sh >> configure: add CONFIG_POSTCOPY option >> savevm: add new section that is used by postcopy >> postcopy: introduce -postcopy and -postcopy-flags option >> postcopy outgoing: add -p and -n option to migrate command >> postcopy: introduce helper functions for postcopy >> postcopy: implement incoming part of postcopy live migration >> postcopy: implement outgoing part of postcopy live migration >> postcopy/outgoing: add forward, backward option to specify the size >> of prefault >> postcopy/outgoing: implement prefault >> migrate: add -m (movebg) option to migrate command >> migration/postcopy: add movebg mode >> >> Makefile.target | 5 + >> arch_init.c | 298 ++++--- >> arch_init.h | 20 + >> block-migration.c | 8 +- >> buffered_file.c | 322 ++++++-- >> buffered_file.h | 32 + >> configure | 12 + >> cpu-all.h | 9 + >> exec-obsolete.h | 1 + >> exec.c | 87 ++- >> hmp-commands.hx | 18 +- >> hmp.c | 10 +- >> linux-headers/linux/umem.h | 42 + >> migration-exec.c | 12 +- >> migration-fd.c | 25 +- >> migration-postcopy-stub.c | 77 ++ >> migration-postcopy.c | 1771 +++++++++++++++++++++++++++++++++++++++ >> migration-tcp.c | 25 +- >> migration-unix.c | 26 +- >> migration.c | 97 ++- >> migration.h | 47 +- >> qapi-schema.json | 4 +- >> qemu-common.h | 2 + >> qemu-file.h | 8 +- >> qemu-options.hx | 25 + >> qmp-commands.hx | 4 +- >> savevm.c | 177 ++++- >> scripts/update-linux-headers.sh | 2 +- >> sysemu.h | 4 +- >> umem.c | 364 ++++++++ >> umem.h | 101 +++ >> vl.c | 16 +- >> vmstate.h | 2 +- >> 33 files changed, 3373 insertions(+), 280 deletions(-) >> create mode 100644 linux-headers/linux/umem.h >> create mode 100644 migration-postcopy-stub.c >> create mode 100644 migration-postcopy.c >> create mode 100644 umem.c >> create mode 100644 umem.h >> >> >> >> >> ------------------------------ >> >> ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] Fwd: [PATCH v2 00/41] postcopy live migration 2012-06-04 14:27 ` Chegu Vinod @ 2012-06-04 15:13 ` Isaku Yamahata 0 siblings, 0 replies; 3+ messages in thread From: Isaku Yamahata @ 2012-06-04 15:13 UTC (permalink / raw) To: Chegu Vinod; +Cc: qemu-devel, kvm On Mon, Jun 04, 2012 at 07:27:25AM -0700, Chegu Vinod wrote: > On 6/4/2012 6:13 AM, Isaku Yamahata wrote: >> On Mon, Jun 04, 2012 at 05:01:30AM -0700, Chegu Vinod wrote: >>> Hello Isaku Yamahata, >> Hi. >> >>> I just saw your patches..Would it be possible to email me a tar bundle of these >>> patches (makes it easier to apply the patches to a copy of the upstream qemu.git) >> I uploaded them to github for those who are interested in it. >> >> git://github.com/yamahata/qemu.git qemu-postcopy-june-04-2012 >> git://github.com/yamahata/linux-umem.git linux-umem-june-04-2012 >> > > Thanks for the pointer... >>> BTW, I am also curious if you have considered using any kind of RDMA features for >>> optimizing the page-faults during postcopy ? >> Yes, RDMA is interesting topic. Can we share your use case/concern/issues? > > > Looking at large sized guests (256GB and higher) running cpu/memory > intensive enterprise workloads. > The concerns are the same...i.e. having a predictable total migration > time, minimal downtime/freeze-time and of course minimal service > degradation to the workload(s) in the VM or the co-located VM's... > > How large of a guest have you tested your changes with and what kind of > workloads have you used so far ? Only up to several GB VM. Off course We'd like to benchmark with real huge VM (several hundred GB), but it's somewhat difficult. >> Thus we can collaborate. >> You may want to see Benoit's results. > > Yes. 'have already seen some of Benoit's results. Great. > Hence the question about use of RDMA techniques for post copy. So far my implementation doesn't used RDMA. >> As long as I know, he has not published >> his code yet. > > Thanks > Vinod > >> >> thanks, >> >>> Thanks >>> Vinod >>> >>> >>> >>> ---------------------------------------------------------------------- >>> >>> Message: 1 >>> Date: Mon, 4 Jun 2012 18:57:02 +0900 >>> From: Isaku Yamahata<yamahata@valinux.co.jp> >>> To: qemu-devel@nongnu.org, kvm@vger.kernel.org >>> Cc: benoit.hudzia@gmail.com, aarcange@redhat.com, aliguori@us.ibm.com, >>> quintela@redhat.com, stefanha@gmail.com, t.hirofuchi@aist.go.jp, >>> dlaor@redhat.com, satoshi.itoh@aist.go.jp, mdroth@linux.vnet.ibm.com, >>> yoshikawa.takuya@oss.ntt.co.jp, owasserm@redhat.com, avi@redhat.com, >>> pbonzini@redhat.com >>> Subject: [Qemu-devel] [PATCH v2 00/41] postcopy live migration >>> Message-ID:<cover.1338802190.git.yamahata@valinux.co.jp> >>> >>> After the long time, we have v2. This is qemu part. >>> The linux kernel part is sent separatedly. >>> >>> Changes v1 -> v2: >>> - split up patches for review >>> - buffered file refactored >>> - many bug fixes >>> Espcially PV drivers can work with postcopy >>> - optimization/heuristic >>> >>> Patches >>> 1 - 30: refactoring exsiting code and preparation >>> 31 - 37: implement postcopy itself (essential part) >>> 38 - 41: some optimization/heuristic for postcopy >>> >>> Intro >>> ===== >>> This patch series implements postcopy live migration.[1] >>> As discussed at KVM forum 2011, dedicated character device is used for >>> distributed shared memory between migration source and destination. >>> Now we can discuss/benchmark/compare with precopy. I believe there are >>> much rooms for improvement. >>> >>> [1] http://wiki.qemu.org/Features/PostCopyLiveMigration >>> >>> >>> Usage >>> ===== >>> You need load umem character device on the host before starting migration. >>> Postcopy can be used for tcg and kvm accelarator. The implementation depend >>> on only linux umem character device. But the driver dependent code is split >>> into a file. >>> I tested only host page size == guest page size case, but the implementation >>> allows host page size != guest page size case. >>> >>> The following options are added with this patch series. >>> - incoming part >>> command line options >>> -postcopy [-postcopy-flags<flags>] >>> where flags is for changing behavior for benchmark/debugging >>> Currently the following flags are available >>> 0: default >>> 1: enable touching page request >>> >>> example: >>> qemu -postcopy -incoming tcp:0:4444 -monitor stdio -machine accel=kvm >>> >>> - outging part >>> options for migrate command >>> migrate [-p [-n] [-m]] URI [<prefault forward> [<prefault backword>]] >>> -p: indicate postcopy migration >>> -n: disable background transferring pages: This is for benchmark/debugging >>> -m: move background transfer of postcopy mode >>> <prefault forward>: The number of forward pages which is sent with on-demand >>> <prefault backward>: The number of backward pages which is sent with >>> on-demand >>> >>> example: >>> migrate -p -n tcp:<dest ip address>:4444 >>> migrate -p -n -m tcp:<dest ip address>:4444 32 0 >>> >>> >>> TODO >>> ==== >>> - benchmark/evaluation. Especially how async page fault affects the result. >>> - improve/optimization >>> At the moment at least what I'm aware of is >>> - making incoming socket non-blocking with thread >>> As page compression is comming, it is impractical to non-blocking read >>> and check if the necessary data is read. >>> - touching pages in incoming qemu process by fd handler seems suboptimal. >>> creating dedicated thread? >>> - outgoing handler seems suboptimal causing latency. >>> - consider on FUSE/CUSE possibility >>> - don't fork umemd, but create thread? >>> >>> basic postcopy work flow >>> ======================== >>> qemu on the destination >>> | >>> V >>> open(/dev/umem) >>> | >>> V >>> UMEM_INIT >>> | >>> V >>> Here we have two file descriptors to >>> umem device and shmem file >>> | >>> | umemd >>> | daemon on the destination >>> | >>> V create pipe to communicate >>> fork()---------------------------------------, >>> | | >>> V | >>> close(socket) V >>> close(shmem) mmap(shmem file) >>> | | >>> V V >>> mmap(umem device) for guest RAM close(shmem file) >>> | | >>> close(umem device) | >>> | | >>> V | >>> wait for ready from daemon<----pipe-----send ready message >>> | | >>> | Here the daemon takes over >>> send ok------------pipe---------------> the owner of the socket >>> | to the source >>> V | >>> entering post copy stage | >>> start guest execution | >>> | | >>> V V >>> access guest RAM read() to get faulted pages >>> | | >>> V V >>> page fault ------------------------------>page offset is returned >>> block | >>> V >>> pull page from the source >>> write the page contents >>> to the shmem. >>> | >>> V >>> unblock<-----------------------------write() to tell served pages >>> the fault handler returns the page >>> page fault is resolved >>> | >>> | pages can be sent >>> | backgroundly >>> | | >>> | V >>> | write() >>> | | >>> V V >>> The specified pages<-----pipe------------request to touch pages >>> are made present by | >>> touching guest RAM. | >>> | | >>> V V >>> reply-------------pipe-------------> release the cached page >>> | madvise(MADV_REMOVE) >>> | | >>> V V >>> >>> all the pages are pulled from the source >>> >>> | | >>> V V >>> the vma becomes anonymous<----------------UMEM_MAKE_VMA_ANONYMOUS >>> (note: I'm not sure if this can be implemented or not) >>> | | >>> V V >>> migration completes exit() >>> >>> >>> >>> >>> Isaku Yamahata (41): >>> arch_init: export sort_ram_list() and ram_save_block() >>> arch_init: export RAM_SAVE_xxx flags for postcopy >>> arch_init/ram_save: introduce constant for ram save version = 4 >>> arch_init: refactor host_from_stream_offset() >>> arch_init/ram_save_live: factor out RAM_SAVE_FLAG_MEM_SIZE case >>> arch_init: refactor ram_save_block() >>> arch_init/ram_save_live: factor out ram_save_limit >>> arch_init/ram_load: refactor ram_load >>> arch_init: introduce helper function to find ram block with id string >>> arch_init: simplify a bit by ram_find_block() >>> arch_init: factor out counting transferred bytes >>> arch_init: factor out setting last_block, last_offset >>> exec.c: factor out qemu_get_ram_ptr() >>> exec.c: export last_ram_offset() >>> savevm: export qemu_peek_buffer, qemu_peek_byte, qemu_file_skip >>> savevm: qemu_pending_size() to return pending buffered size >>> savevm, buffered_file: introduce method to drain buffer of buffered >>> file >>> QEMUFile: add qemu_file_fd() for later use >>> savevm/QEMUFile: drop qemu_stdio_fd >>> savevm/QEMUFileSocket: drop duplicated member fd >>> savevm: rename QEMUFileSocket to QEMUFileFD, socket_close to fd_close >>> savevm/QEMUFile: introduce qemu_fopen_fd >>> migration.c: remove redundant line in migrate_init() >>> migration: export migrate_fd_completed() and migrate_fd_cleanup() >>> migration: factor out parameters into MigrationParams >>> buffered_file: factor out buffer management logic >>> buffered_file: Introduce QEMUFileNonblock for nonblock write >>> buffered_file: add qemu_file to read/write to buffer in memory >>> umem.h: import Linux umem.h >>> update-linux-headers.sh: teach umem.h to update-linux-headers.sh >>> configure: add CONFIG_POSTCOPY option >>> savevm: add new section that is used by postcopy >>> postcopy: introduce -postcopy and -postcopy-flags option >>> postcopy outgoing: add -p and -n option to migrate command >>> postcopy: introduce helper functions for postcopy >>> postcopy: implement incoming part of postcopy live migration >>> postcopy: implement outgoing part of postcopy live migration >>> postcopy/outgoing: add forward, backward option to specify the size >>> of prefault >>> postcopy/outgoing: implement prefault >>> migrate: add -m (movebg) option to migrate command >>> migration/postcopy: add movebg mode >>> >>> Makefile.target | 5 + >>> arch_init.c | 298 ++++--- >>> arch_init.h | 20 + >>> block-migration.c | 8 +- >>> buffered_file.c | 322 ++++++-- >>> buffered_file.h | 32 + >>> configure | 12 + >>> cpu-all.h | 9 + >>> exec-obsolete.h | 1 + >>> exec.c | 87 ++- >>> hmp-commands.hx | 18 +- >>> hmp.c | 10 +- >>> linux-headers/linux/umem.h | 42 + >>> migration-exec.c | 12 +- >>> migration-fd.c | 25 +- >>> migration-postcopy-stub.c | 77 ++ >>> migration-postcopy.c | 1771 +++++++++++++++++++++++++++++++++++++++ >>> migration-tcp.c | 25 +- >>> migration-unix.c | 26 +- >>> migration.c | 97 ++- >>> migration.h | 47 +- >>> qapi-schema.json | 4 +- >>> qemu-common.h | 2 + >>> qemu-file.h | 8 +- >>> qemu-options.hx | 25 + >>> qmp-commands.hx | 4 +- >>> savevm.c | 177 ++++- >>> scripts/update-linux-headers.sh | 2 +- >>> sysemu.h | 4 +- >>> umem.c | 364 ++++++++ >>> umem.h | 101 +++ >>> vl.c | 16 +- >>> vmstate.h | 2 +- >>> 33 files changed, 3373 insertions(+), 280 deletions(-) >>> create mode 100644 linux-headers/linux/umem.h >>> create mode 100644 migration-postcopy-stub.c >>> create mode 100644 migration-postcopy.c >>> create mode 100644 umem.c >>> create mode 100644 umem.h >>> >>> >>> >>> >>> ------------------------------ >>> >>> > -- yamahata ^ permalink raw reply 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[not found] <4FCCA39A.1050300@hp.com>
2012-06-04 13:13 ` [Qemu-devel] Fwd: [PATCH v2 00/41] postcopy live migration Isaku Yamahata
2012-06-04 14:27 ` Chegu Vinod
2012-06-04 15:13 ` Isaku Yamahata
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