Re: [libvirt] [PATCHv5 0/8] bulk stats: QEMU implementation

This patchset enhances the QEMU support for the new bulk stats API to include equivalents of these APIs: virDomainBlockInfo virDomainGetInfo - for balloon stats virDomainGetCPUStats virDomainBlockStatsFlags virDomainInterfaceStats virDomainGetVcpusFlags virDomainGetVcpus This subset of API is the one oVirt relies on. Scale/stress test on an oVirt test environment is in progress. The patchset is organized as follows: - the first patch enhances the internal stats gathering API to accomodate the needs of the groups which extract information using QEMU monitor jobs. - the next five patches implement the bulk stats groups, extracting helpers where do refactoring to extract internal helpers every time it is feasible and convenient. - the seventh patch enhances the virsh domstats command with options to use the new bulk stats. - the last patch enhances the block stats group adding the wr_highest_offset information, needed by oVirt for thin provisioned disks. ChangeLog v5: address reviewer's comment - Eric pointed out a possible flaw in balloon stats if QEMU monitor needs to be queried. A proper fix require further discussion and API changes (possbily just a new flag); However, since the balloon event is available in QEMU >= 1.2, I just dropped the query and relied on the event instead. Support for older QEMUs will be reintroduced, if needed, with following patches. - fix: per-domain monitor check and reporting. (pointed out by Peter) - reset last error when fail silently. (pointed out by Peter) v4: address reviewer's comment - addressed reviewers comments (Peter, Wang Rui). - pushed domain check into group stats functions. This follows the strategy to gather and report as much data as possible, silently skipping errors along the way. - moved the block allocation patch to the end of the series. v3: more polishing and fixes after first review - addressed Eric's comments. - squashed patches which extracts helpers with patches which use them. - changed gathering strategy: now code tries to reap as much information as possible instead to give up and bail out with error. Only critical errors cause the bulk stats to fail. - moved away from the transfer semantics. I find it error-prone and not flexible enough, I'd like to avoid as much as possible. - rearranged helpers to have one single QEMU query job with many monitor jobs nested inside. - fixed docs. - implemented missing virsh domstats bits. in v2: polishing and optimizations. - incorporated feedback from Li Wei (thanks). - added documentation. - optimized block group to gather all the information with just one call to QEMU monitor. - stripped to bare bones merged the 'block info' group into the 'block' group - oVirt actually needs just one stat from there. - reorganized the keys to be more consistent and shorter. Francesco Romani (8): qemu: bulk stats: extend internal collection API qemu: bulk stats: implement CPU stats group qemu: bulk stats: implement balloon group qemu: bulk stats: implement VCPU group qemu: bulk stats: implement interface group qemu: bulk stats: implement block group virsh: add options to query bulk stats group qemu: bulk stats: add block allocation information include/libvirt/libvirt.h.in | 5 + src/libvirt.c | 61 +++++ src/qemu/qemu_driver.c | 530 +++++++++++++++++++++++++++++++++++++------ src/qemu/qemu_monitor.c | 26 +++ src/qemu/qemu_monitor.h | 21 ++ src/qemu/qemu_monitor_json.c | 227 +++++++++++++----- src/qemu/qemu_monitor_json.h | 4 + tools/virsh-domain-monitor.c | 35 +++ tools/virsh.pod | 4 +- 9 files changed, 777 insertions(+), 136 deletions(-)