[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 2/2] migration: calculate downtime on dst side
|
From: |
Alexey Perevalov |
|
Subject: |
[Qemu-devel] [PATCH 2/2] migration: calculate downtime on dst side |
|
Date: |
Sat, 18 Mar 2017 18:13:23 +0300 |
This patch provides downtime calculation per vCPU,
as a summary and as a overlapped value for all vCPUs.
This approach just keeps tree with page fault addr as a key,
and t1-t2 interval of pagefault time and page copy time, with
affected vCPU bit mask.
For more implementation details please see comment to
get_postcopy_total_downtime function.
Signed-off-by: Alexey Perevalov <address@hidden>
---
include/migration/migration.h | 11 ++
migration/migration.c | 238 +++++++++++++++++++++++++++++++++++++++++-
migration/postcopy-ram.c | 61 ++++++++++-
migration/savevm.c | 2 +
migration/trace-events | 10 +-
5 files changed, 318 insertions(+), 4 deletions(-)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 5720c88..8f9af77 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -123,10 +123,21 @@ struct MigrationIncomingState {
/* See savevm.c */
LoadStateEntry_Head loadvm_handlers;
+
+ /*
+ * Tree for keeping postcopy downtime,
+ * necessary to calculate correct downtime, during multiple
+ * vm suspends, it keeps host page address as a key and
+ * DowntimeDuration as a data
+ */
+ GTree *postcopy_downtime;
};
MigrationIncomingState *migration_incoming_get_current(void);
void migration_incoming_state_destroy(void);
+void mark_postcopy_downtime_begin(uint64_t addr, int cpu);
+void mark_postcopy_downtime_end(uint64_t addr);
+int64_t get_postcopy_total_downtime(void);
/*
* An outstanding page request, on the source, having been received
diff --git a/migration/migration.c b/migration/migration.c
index 54060f7..57d71e1 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -77,6 +77,12 @@ static NotifierList migration_state_notifiers =
static bool deferred_incoming;
+typedef struct {
+ int64_t begin;
+ int64_t end;
+ uint64_t cpus;
+} DowntimeDuration;
+
/*
* Current state of incoming postcopy; note this is not part of
* MigrationIncomingState since it's state is used during cleanup
@@ -117,6 +123,21 @@ MigrationState *migrate_get_current(void)
return ¤t_migration;
}
+static gint addr_compare(gconstpointer a, gconstpointer b,
+ gpointer user_data G_GNUC_UNUSED)
+{
+ if (a == b)
+ return 0;
+ else if (a > b)
+ return 1;
+ return -1;
+}
+
+static void destroy_downtime_duration(gpointer data)
+{
+ free(data);
+}
+
MigrationIncomingState *migration_incoming_get_current(void)
{
static bool once;
@@ -128,6 +149,9 @@ MigrationIncomingState *migration_incoming_get_current(void)
QLIST_INIT(&mis_current.loadvm_handlers);
qemu_mutex_init(&mis_current.rp_mutex);
qemu_event_init(&mis_current.main_thread_load_event, false);
+ mis_current.postcopy_downtime = g_tree_new_full(addr_compare,
+ NULL, NULL,
+ destroy_downtime_duration);
once = true;
}
return &mis_current;
@@ -138,10 +162,13 @@ void migration_incoming_state_destroy(void)
struct MigrationIncomingState *mis = migration_incoming_get_current();
qemu_event_destroy(&mis->main_thread_load_event);
+ if (mis->postcopy_downtime) {
+ g_tree_destroy(mis->postcopy_downtime);
+ mis->postcopy_downtime = NULL;
+ }
loadvm_free_handlers(mis);
}
-
typedef struct {
bool optional;
uint32_t size;
@@ -1119,7 +1146,6 @@ MigrationState *migrate_init(const MigrationParams
*params)
s->last_req_rb = NULL;
error_free(s->error);
s->error = NULL;
-
migrate_set_state(&s->state, MIGRATION_STATUS_NONE,
MIGRATION_STATUS_SETUP);
QSIMPLEQ_INIT(&s->src_page_requests);
@@ -2109,3 +2135,211 @@ PostcopyState postcopy_state_set(PostcopyState
new_state)
return atomic_xchg(&incoming_postcopy_state, new_state);
}
+void mark_postcopy_downtime_begin(uint64_t addr, int cpu)
+{
+ MigrationIncomingState *mis = migration_incoming_get_current();
+ DowntimeDuration *dd;
+ if (!mis || !mis->postcopy_downtime) {
+ error_report("Migration incoming state should exists mis %p", mis);
+ return;
+ }
+
+ dd = g_tree_lookup(mis->postcopy_downtime, (gpointer)addr); /* !!! cast */
+ if (!dd) {
+ dd = (DowntimeDuration *)g_malloc0(sizeof(DowntimeDuration));
+ g_tree_insert(mis->postcopy_downtime, (gpointer)addr, (gpointer)dd);
+ }
+
+ if (cpu < 0)
+ /* assume in this situation all vCPUs are sleeping */
+ dd->cpus = ~0u;
+ else
+ set_bit(cpu, &dd->cpus);
+
+ /*
+ * overwrite previously set dd->begin, if that page already was
+ * faulted on another cpu
+ */
+ dd->begin = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ trace_mark_postcopy_downtime_begin(addr, dd, dd->begin, cpu);
+}
+
+void mark_postcopy_downtime_end(uint64_t addr)
+{
+ MigrationIncomingState *mis = migration_incoming_get_current();
+ DowntimeDuration *dd;
+ if (!mis || !mis->postcopy_downtime) {
+ error_report("Migration incoming state should exists mis %p", mis);
+ return;
+ }
+
+ dd = g_tree_lookup(mis->postcopy_downtime, (gpointer)addr);
+ if (!dd) {
+ /* error_report("Could not populate downtime duration completion time
\n\
+ There is no downtime duration for 0x%"PRIx64, addr); */
+ return;
+ }
+
+ dd->end = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ trace_mark_postcopy_downtime_end(addr, dd, dd->end);
+}
+
+typedef struct {
+ int64_t tp; /* point in time */
+ bool is_end;
+ int64_t cpus; /* cpus bit mask */
+} OverlapDowntime;
+
+static gboolean populate_downtime_points(gpointer key, gpointer value,
+ gpointer data)
+{
+ DowntimeDuration *dd = (DowntimeDuration *)value;
+ GPtrArray *interval = (GPtrArray *)data;
+ OverlapDowntime *od_begin = g_malloc0(sizeof(OverlapDowntime));
+ OverlapDowntime *od_end = g_malloc0(sizeof(OverlapDowntime));
+
+ od_begin->tp = dd->begin;
+ od_begin->is_end = false;
+ od_begin->cpus = dd->cpus;
+ g_ptr_array_add(interval, od_begin);
+
+ od_end->tp = dd->end;
+ od_end->is_end = true;
+ od_end->cpus = dd->cpus;
+ g_ptr_array_add(interval, od_end);
+
+ if (dd->end && dd->begin)
+ trace_sumup_downtime_duration(dd->end - dd->begin, (uint64_t)key,
dd->cpus);
+ return FALSE;
+}
+
+static gboolean calculate_per_cpu(gpointer key, gpointer value,
+ gpointer data)
+{
+ int *downtime_cpu = (int *)data;
+ DowntimeDuration *dd = (DowntimeDuration *)value;
+ int cpu_iter;
+ for (cpu_iter = 0; cpu_iter < smp_cpus; cpu_iter++) {
+ if (test_bit(cpu_iter, &dd->cpus) && dd->end && dd->begin)
+ downtime_cpu[cpu_iter] += dd->end - dd->begin;
+ }
+ return FALSE;
+}
+
+static gint compare_downtime(gconstpointer a, gconstpointer b)
+{
+ DowntimeDuration *dda = (DowntimeDuration *)a;
+ DowntimeDuration *ddb = (DowntimeDuration *)b;
+ return dda->begin - ddb->begin;
+}
+
+static uint64_t get_sufficient_smp_cpus(void)
+{
+ int i;
+ static uint64_t sufficient_cpus;
+ for (i = 0; i < smp_cpus; i++)
+ {
+ set_bit(i, &sufficient_cpus);
+ }
+ return sufficient_cpus;
+}
+
+/*
+ * This function calculates downtime per cpu and trace it
+ *
+ * Also it calculates total downtime as an interval's overlap,
+ * for many vCPU.
+ *
+ * The approach is following:
+ * Initially intervals are represented in tree where key is
+ * pagefault address, and values:
+ * begin - page fault time
+ * end - page load time
+ * cpus - bit mask shows affected cpus
+ *
+ * To calculate overlap on all cpus, intervals converted into
+ * array of points in time (downtime_points), the size of
+ * array is 2 * number of nodes in tree of intervals (2 array
+ * elements per one in element of interval).
+ * Each element is marked as end (E) or as start (S) of interval.
+ * The overlap downtime will be calculated for SE, only in case
+ * there is sequence S(0..N)E(M) for every vCPU.
+ *
+ * As example we have 3 CPU
+ *
+ * S1 E1 S1 E1
+ * -----***********------------xxx***************------------------------> CPU1
+ *
+ * S2 E2
+ * ------------****************xxx---------------------------------------> CPU2
+ *
+ * S3 E3
+ * ------------------------****xxx********-------------------------------> CPU3
+ *
+ * We have sequence S1,S2,E1,S3,S1,E2,E3,E1
+ * S2,E1 - doesn't match condition due to sequence S1,S2,E1 doesn't include
CPU3,
+ * S3,S1,E2 - sequenece includes all CPUs, in this case overlap will be S1,E2
+ *
+ */
+int64_t get_postcopy_total_downtime(void)
+{
+ MigrationIncomingState *mis = migration_incoming_get_current();
+ int64_t total_downtime = 0; /* for total overlapped downtime */
+ const int intervals = g_tree_nnodes(mis->postcopy_downtime);
+ const int points = 2 * intervals;
+ uint64_t sufficient_smp_cpus = get_sufficient_smp_cpus();
+ int point_iter, start_point_iter;
+ GPtrArray *downtime_points = g_ptr_array_sized_new(points);
+ /* for summary downtime per cpu */
+ int *downtime_cpu = g_malloc0(smp_cpus * sizeof(int));
+ if (!mis || !mis->postcopy_downtime) {
+ error_report("Migration incoming state should exists, mis %p", mis);
+ return -1;
+ }
+
+ /* make downtime points S/E from interval */
+ g_tree_foreach(mis->postcopy_downtime, populate_downtime_points,
+ downtime_points);
+ g_tree_foreach(mis->postcopy_downtime, calculate_per_cpu, downtime_cpu);
+
+ /* just for RFC patch */
+ for (point_iter = 0; point_iter < smp_cpus; point_iter++)
+ {
+ trace_downtime_per_cpu(point_iter, downtime_cpu[point_iter]);
+ }
+
+ g_ptr_array_sort(downtime_points, compare_downtime);
+
+ for (point_iter = 1; point_iter < points; point_iter++) {
+ OverlapDowntime *od = g_ptr_array_index(downtime_points, point_iter);
+ uint64_t cur_cpus = od->cpus;
+ int smp_cpus_i = smp_cpus;
+ OverlapDowntime *prev_od = g_ptr_array_index(downtime_points,
+ point_iter - 1);
+ /* we need sequence SE */
+ if (!od->is_end || prev_od->is_end)
+ continue;
+
+ for (start_point_iter = point_iter - 1;
+ start_point_iter >= 0 && smp_cpus_i;
+ start_point_iter--, smp_cpus_i--) {
+ OverlapDowntime *t_od = g_ptr_array_index(downtime_points,
+ start_point_iter);
+ /* should be S */
+ if (t_od->is_end)
+ break;
+
+ cur_cpus |= t_od->cpus;
+ if (sufficient_smp_cpus & cur_cpus) {
+ total_downtime += od->tp - prev_od->tp;
+ /* situation when one S point represents all vCPU is possible
*/
+ break;
+ }
+ }
+ }
+ trace_get_postcopy_total_downtime(g_tree_nnodes(mis->postcopy_downtime),
+ total_downtime);
+
+ g_ptr_array_free(downtime_points, TRUE);
+ return total_downtime;
+}
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index dc80dbb..3bd9db0 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -23,6 +23,7 @@
#include "migration/postcopy-ram.h"
#include "sysemu/sysemu.h"
#include "sysemu/balloon.h"
+#include <sys/param.h>
#include "qemu/error-report.h"
#include "trace.h"
@@ -404,6 +405,60 @@ static int ram_block_enable_notify(const char *block_name,
void *host_addr,
return 0;
}
+#define PROC_LEN 1024
+static void trace_for_thread(const char *msg, pid_t thread_id)
+{
+ const char *status_file_frmt = "/proc/%d/status";
+ char status_file_path[MAXPATHLEN];
+ char proc_name[PROC_LEN];
+ char proc_status[PROC_LEN];
+ char *line = NULL;
+ FILE *f;
+ ssize_t read;
+ size_t len;
+
+ sprintf(status_file_path, status_file_frmt, thread_id);
+ f = fopen(status_file_path, "r");
+ if (!f) {
+ error_report("can't open %s", status_file_path);
+ return;
+ }
+
+ memset(proc_name, 0, sizeof(proc_name));
+ memset(proc_status, 0, sizeof(proc_status));
+
+ while ((read = getline(&line, &len, f)) != -1) {
+ if (strstr(line, "Name"))
+ strncpy(proc_name, line, sizeof(proc_name));
+ if (strstr(line, "State"))
+ strncpy(proc_status, line, sizeof(proc_status));
+ }
+
+ free(line);
+ trace_vcpu_thread_status(msg, thread_id, proc_name, proc_status);
+}
+
+static int defined_mem_fault_cpu_index(pid_t pid)
+{
+ CPUState *cpu_iter;
+
+ CPU_FOREACH(cpu_iter) {
+ if (cpu_iter->thread_id == pid)
+ return cpu_iter->cpu_index;
+ }
+ trace_for_thread("can't find cpu_index for thread id", pid);
+ return -1;
+}
+
+static void trace_cpu_state(void)
+{
+ CPUState *cpu_iter;
+ CPU_FOREACH(cpu_iter) {
+ trace_for_thread("vCPU", cpu_iter->thread_id);
+ trace_postcopy_vcpu_running(cpu_iter->cpu_index, cpu_iter->running);
+ }
+}
+
/*
* Handle faults detected by the USERFAULT markings
*/
@@ -445,6 +500,7 @@ static void *postcopy_ram_fault_thread(void *opaque)
}
ret = read(mis->userfault_fd, &msg, sizeof(msg));
+ trace_cpu_state();
if (ret != sizeof(msg)) {
if (errno == EAGAIN) {
/*
@@ -481,8 +537,10 @@ static void *postcopy_ram_fault_thread(void *opaque)
rb_offset &= ~(qemu_ram_pagesize(rb) - 1);
trace_postcopy_ram_fault_thread_request(msg.arg.pagefault.address,
qemu_ram_get_idstr(rb),
- rb_offset);
+ rb_offset,
msg.arg.pagefault.pid);
+ mark_postcopy_downtime_begin(msg.arg.pagefault.address,
+ defined_mem_fault_cpu_index(msg.arg.pagefault.pid));
/*
* Send the request to the source - we want to request one
* of our host page sizes (which is >= TPS)
@@ -577,6 +635,7 @@ int postcopy_place_page(MigrationIncomingState *mis, void
*host, void *from,
return -e;
}
+ mark_postcopy_downtime_end((uint64_t)host);
trace_postcopy_place_page(host);
return 0;
diff --git a/migration/savevm.c b/migration/savevm.c
index 3b19a4a..e12c0a2 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1630,6 +1630,7 @@ static void loadvm_postcopy_handle_run_bh(void *opaque)
if (autostart) {
/* Hold onto your hats, starting the CPU */
+ trace_loadvm_postcopy_vm_start(get_postcopy_total_downtime());
vm_start();
} else {
/* leave it paused and let management decide when to start the CPU */
@@ -1930,6 +1931,7 @@ qemu_loadvm_section_part_end(QEMUFile *f,
MigrationIncomingState *mis)
return -EINVAL;
}
+ trace_loadvm_postcopy_vm_start(get_postcopy_total_downtime());
return 0;
}
diff --git a/migration/trace-events b/migration/trace-events
index 7372ce2..8a21684 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -44,6 +44,7 @@ vmstate_subsection_save_loop(const char *name, const char
*sub) "%s/%s"
vmstate_subsection_save_top(const char *idstr) "%s"
vmstate_load(const char *idstr, const char *vmsd_name) "%s, %s"
qemu_announce_self_iter(const char *mac) "%s"
+loadvm_postcopy_vm_start(int64_t downtime) "%"PRId64
# migration/vmstate.c
vmstate_load_field_error(const char *field, int ret) "field \"%s\" load
failed, ret = %d"
@@ -110,6 +111,11 @@ process_incoming_migration_co_end(int ret, int ps) "ret=%d
postcopy-state=%d"
process_incoming_migration_co_postcopy_end_main(void) ""
migration_set_incoming_channel(void *ioc, const char *ioctype) "ioc=%p
ioctype=%s"
migration_set_outgoing_channel(void *ioc, const char *ioctype, const char
*hostname) "ioc=%p ioctype=%s hostname=%s"
+mark_postcopy_downtime_begin(uint64_t addr, void *dd, int64_t time, int cpu)
"addr 0x%" PRIx64 " dd %p time %" PRId64 " cpu %d"
+mark_postcopy_downtime_end(uint64_t addr, void *dd, int64_t time) "addr 0x%"
PRIx64 " dd %p time %" PRId64
+get_postcopy_total_downtime(int num, int64_t total) "faults %d, total downtime
%" PRId64
+sumup_downtime_duration(int64_t downtime, uint64_t addr, int cpubit) "downtime
%" PRId64 " addr 0x%" PRIx64 "cpus %d"
+downtime_per_cpu(int cpu_index, int downtime) "downtime cpu[%d]=%d"
# migration/rdma.c
qemu_rdma_accept_incoming_migration(void) ""
@@ -186,7 +192,7 @@ postcopy_ram_enable_notify(void) ""
postcopy_ram_fault_thread_entry(void) ""
postcopy_ram_fault_thread_exit(void) ""
postcopy_ram_fault_thread_quit(void) ""
-postcopy_ram_fault_thread_request(uint64_t hostaddr, const char *ramblock,
size_t offset) "Request for HVA=%" PRIx64 " rb=%s offset=%zx"
+postcopy_ram_fault_thread_request(uint64_t hostaddr, const char *ramblock,
size_t offset, int pid) "Request for HVA=%" PRIx64 " rb=%s offset=%zx %d"
postcopy_ram_incoming_cleanup_closeuf(void) ""
postcopy_ram_incoming_cleanup_entry(void) ""
postcopy_ram_incoming_cleanup_exit(void) ""
@@ -195,6 +201,8 @@ save_xbzrle_page_skipping(void) ""
save_xbzrle_page_overflow(void) ""
ram_save_iterate_big_wait(uint64_t milliconds, int iterations) "big wait: %"
PRIu64 " milliseconds, %d iterations"
ram_load_complete(int ret, uint64_t seq_iter) "exit_code %d seq iteration %"
PRIu64
+vcpu_thread_status(const char *msg, int tpid, char *name, char *status) "%s
host_tid %d %s %s"
+postcopy_vcpu_running(int cpu_index, int is_running) "cpu %d running %d"
# migration/exec.c
migration_exec_outgoing(const char *cmd) "cmd=%s"
--
1.8.3.1