From 3937ef9cf4ff9d6d5aba8b76d9db5e44ae15a2aa Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Sat, 6 Dec 2014 00:14:43 -0700 Subject: [PATCH] getstats: crawl backing chain for qemu Wire up backing chain recursion. For the first time, it is now possible to get libvirt to expose that qemu tracks read statistics on backing files, as well as report maximum extent written on a backing file during a block-commit operation. For a running domain, where one of the two images has a backing file, I see the traditional output: $ virsh domstats --block testvm2 Domain: 'testvm2' block.count=2 block.0.name=vda block.0.path=/tmp/wrapper.qcow2 block.0.rd.reqs=1 block.0.rd.bytes=512 block.0.rd.times=28858 block.0.wr.reqs=0 block.0.wr.bytes=0 block.0.wr.times=0 block.0.fl.reqs=0 block.0.fl.times=0 block.0.allocation=0 block.0.capacity=1310720000 block.0.physical=200704 block.1.name=vdb block.1.path=/dev/sda7 block.1.rd.reqs=0 block.1.rd.bytes=0 block.1.rd.times=0 block.1.wr.reqs=0 block.1.wr.bytes=0 block.1.wr.times=0 block.1.fl.reqs=0 block.1.fl.times=0 block.1.allocation=0 block.1.capacity=1310720000 vs. the new output: $ virsh domstats --block --backing testvm2 Domain: 'testvm2' block.count=3 block.0.name=vda block.0.path=/tmp/wrapper.qcow2 block.0.rd.reqs=1 block.0.rd.bytes=512 block.0.rd.times=28858 block.0.wr.reqs=0 block.0.wr.bytes=0 block.0.wr.times=0 block.0.fl.reqs=0 block.0.fl.times=0 block.0.allocation=0 block.0.capacity=1310720000 block.0.physical=200704 block.1.name=vda block.1.path=/dev/sda6 block.1.backingIndex=1 block.1.rd.reqs=0 block.1.rd.bytes=0 block.1.rd.times=0 block.1.wr.reqs=0 block.1.wr.bytes=0 block.1.wr.times=0 block.1.fl.reqs=0 block.1.fl.times=0 block.1.allocation=327680 block.1.capacity=786432000 block.2.name=vdb block.2.path=/dev/sda7 block.2.rd.reqs=0 block.2.rd.bytes=0 block.2.rd.times=0 block.2.wr.reqs=0 block.2.wr.bytes=0 block.2.wr.times=0 block.2.fl.reqs=0 block.2.fl.times=0 block.2.allocation=0 block.2.capacity=1310720000 I may later do a patch that trims the output to avoid 0 stats, particularly for backing files (which are more likely to have 0 stats, at least for write statistics when no block-commit is performed). Also, I still plan to expose physical size information (qemu doesn't expose it yet, so it requires a stat, and for block devices, a further open/seek operation). But this patch is good enough without worrying about that yet. * src/qemu/qemu_driver.c (QEMU_DOMAIN_STATS_BACKING): New internal enum bit. (qemuConnectGetAllDomainStats): Recognize new user flag, and pass details to... (qemuDomainGetStatsBlock): ...here, where we can do longer recursion. (qemuDomainGetStatsOneBlock): Output new field. Signed-off-by: Eric Blake --- src/qemu/qemu_driver.c | 61 +++++++++++++++++++++++++++++++++--------- 1 file changed, 49 insertions(+), 12 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index ec5ef0ab12..89578e1dc7 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -18277,8 +18277,10 @@ qemuDomainGetStatsState(virQEMUDriverPtr driver ATTRIBUTE_UNUSED, typedef enum { - QEMU_DOMAIN_STATS_HAVE_JOB = (1 << 0), /* job is entered, monitor can be - accessed */ + QEMU_DOMAIN_STATS_HAVE_JOB = 1 << 0, /* job is entered, monitor can be + accessed */ + QEMU_DOMAIN_STATS_BACKING = 1 << 1, /* include backing chain in + block stats */ } qemuDomainStatsFlags; @@ -18525,6 +18527,19 @@ qemuDomainGetStatsInterface(virQEMUDriverPtr driver ATTRIBUTE_UNUSED, #undef QEMU_ADD_NET_PARAM +#define QEMU_ADD_BLOCK_PARAM_UI(record, maxparams, num, name, value) \ + do { \ + char param_name[VIR_TYPED_PARAM_FIELD_LENGTH]; \ + snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH, \ + "block.%zu.%s", num, name); \ + if (virTypedParamsAddUInt(&(record)->params, \ + &(record)->nparams, \ + maxparams, \ + param_name, \ + value) < 0) \ + goto cleanup; \ + } while (0) + /* expects a LL, but typed parameter must be ULL */ #define QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, num, name, value) \ do { \ @@ -18562,20 +18577,27 @@ qemuDomainGetStatsOneBlock(virQEMUDriverPtr driver, virDomainDiskDefPtr disk, virStorageSourcePtr src, size_t block_idx, + unsigned int backing_idx, bool abbreviated, virHashTablePtr stats) { qemuBlockStats *entry; int ret = -1; + char *alias = NULL; + + if (disk->info.alias) + alias = qemuDomainStorageAlias(disk->info.alias, backing_idx); QEMU_ADD_NAME_PARAM(record, maxparams, "block", "name", block_idx, disk->dst); if (virStorageSourceIsLocalStorage(src) && src->path) QEMU_ADD_NAME_PARAM(record, maxparams, "block", "path", block_idx, src->path); + if (backing_idx) + QEMU_ADD_BLOCK_PARAM_UI(record, maxparams, block_idx, "backingIndex", + backing_idx); - if (abbreviated || !disk->info.alias || - !(entry = virHashLookup(stats, disk->info.alias))) { + if (abbreviated || !alias || !(entry = virHashLookup(stats, alias))) { if (virStorageSourceIsEmpty(src)) { ret = 0; goto cleanup; @@ -18624,6 +18646,7 @@ qemuDomainGetStatsOneBlock(virQEMUDriverPtr driver, ret = 0; cleanup: + VIR_FREE(alias); return ret; } @@ -18643,14 +18666,17 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver, bool abbreviated = false; virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); int count_index = -1; + size_t visited = 0; + bool visitBacking = !!(privflags & QEMU_DOMAIN_STATS_BACKING); if (!HAVE_JOB(privflags) || !virDomainObjIsActive(dom)) { abbreviated = true; /* it's ok, just go ahead silently */ } else { qemuDomainObjEnterMonitor(driver, dom); - rc = qemuMonitorGetAllBlockStatsInfo(priv->mon, &stats, false); + rc = qemuMonitorGetAllBlockStatsInfo(priv->mon, &stats, + visitBacking); ignore_value(qemuMonitorBlockStatsUpdateCapacity(priv->mon, stats, - false)); + visitBacking)); qemuDomainObjExitMonitor(driver, dom); if (rc < 0) { @@ -18667,14 +18693,21 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver, for (i = 0; i < dom->def->ndisks; i++) { virDomainDiskDefPtr disk = dom->def->disks[i]; + virStorageSourcePtr src = disk->src; + unsigned int backing_idx = 0; - if (qemuDomainGetStatsOneBlock(driver, cfg, dom, record, maxparams, - disk, disk->src, i, abbreviated, - stats) < 0) - goto cleanup; + while (src && (backing_idx == 0 || visitBacking)) { + if (qemuDomainGetStatsOneBlock(driver, cfg, dom, record, maxparams, + disk, src, visited, backing_idx, + abbreviated, stats) < 0) + goto cleanup; + visited++; + backing_idx++; + src = src->backingStore; + } } - record->params[count_index].value.ui = i; + record->params[count_index].value.ui = visited; ret = 0; cleanup: @@ -18818,11 +18851,13 @@ qemuConnectGetAllDomainStats(virConnectPtr conn, unsigned int domflags = 0; if (ndoms) - virCheckFlags(VIR_CONNECT_GET_ALL_DOMAINS_STATS_ENFORCE_STATS, -1); + virCheckFlags(VIR_CONNECT_GET_ALL_DOMAINS_STATS_BACKING | + VIR_CONNECT_GET_ALL_DOMAINS_STATS_ENFORCE_STATS, -1); else virCheckFlags(VIR_CONNECT_LIST_DOMAINS_FILTERS_ACTIVE | VIR_CONNECT_LIST_DOMAINS_FILTERS_PERSISTENT | VIR_CONNECT_LIST_DOMAINS_FILTERS_STATE | + VIR_CONNECT_GET_ALL_DOMAINS_STATS_BACKING | VIR_CONNECT_GET_ALL_DOMAINS_STATS_ENFORCE_STATS, -1); if (virConnectGetAllDomainStatsEnsureACL(conn) < 0) @@ -18872,6 +18907,8 @@ qemuConnectGetAllDomainStats(virConnectPtr conn, domflags |= QEMU_DOMAIN_STATS_HAVE_JOB; /* else: without a job it's still possible to gather some data */ + if (flags & VIR_CONNECT_GET_ALL_DOMAINS_STATS_BACKING) + domflags |= QEMU_DOMAIN_STATS_BACKING; if (qemuDomainGetStats(conn, dom, stats, &tmp, domflags) < 0) goto endjob;