[libvirt] [PATCH v2] examples: Introduce domtop
Michal Privoznik
mprivozn at redhat.com
Fri Jul 18 09:08:00 UTC 2014
There's this question on the list that is asked over and over again.
How do I get {cpu, memory, ...} usage in percentage? Or its modified
version: How do I plot nice graphs like virt-manager does?
It would be nice if we have an example to inspire people. And that's
what domtop should do. Yes, it could be written in different ways, but
I've chosen this one as I think it show explicitly what users need to
implement in order to imitate virt-manager's graphing.
Note: The usage is displayed from host perspective. That is, how much
host CPUs the domain is using. But it should be fairly simple to
switch do just guest CPU usage if needed.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
.gitignore | 1 +
Makefile.am | 2 +-
cfg.mk | 2 +-
configure.ac | 1 +
examples/domtop/Makefile.am | 27 +++
examples/domtop/domtop.c | 400 ++++++++++++++++++++++++++++++++++++++++++++
libvirt.spec.in | 2 +-
7 files changed, 432 insertions(+), 3 deletions(-)
create mode 100644 examples/domtop/Makefile.am
create mode 100644 examples/domtop/domtop.c
diff --git a/.gitignore b/.gitignore
index 2d4d401..90fee91 100644
--- a/.gitignore
+++ b/.gitignore
@@ -75,6 +75,7 @@
/examples/dominfo/info1
/examples/domsuspend/suspend
/examples/dommigrate/dommigrate
+/examples/domtop/domtop
/examples/hellolibvirt/hellolibvirt
/examples/openauth/openauth
/gnulib/lib/*
diff --git a/Makefile.am b/Makefile.am
index a374e1a..4aafe94 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -24,7 +24,7 @@ SUBDIRS = . gnulib/lib include src daemon tools docs gnulib/tests \
examples/dominfo examples/domsuspend examples/apparmor \
examples/xml/nwfilter examples/openauth examples/systemtap \
tools/wireshark examples/dommigrate \
- examples/lxcconvert
+ examples/lxcconvert examples/domtop
ACLOCAL_AMFLAGS = -I m4
diff --git a/cfg.mk b/cfg.mk
index c3d89a0..0559edd 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -1078,7 +1078,7 @@ exclude_file_name_regexp--sc_prohibit_sprintf = \
exclude_file_name_regexp--sc_prohibit_strncpy = ^src/util/virstring\.c$$
exclude_file_name_regexp--sc_prohibit_strtol = \
- ^(src/util/.*|examples/domsuspend/suspend)\.c$$
+ ^(src/util/.*|examples/dom.*/.*)\.c$$
exclude_file_name_regexp--sc_prohibit_xmlGetProp = ^src/util/virxml\.c$$
diff --git a/configure.ac b/configure.ac
index 8001e24..f37c716 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2755,6 +2755,7 @@ AC_CONFIG_FILES([\
examples/domsuspend/Makefile \
examples/dominfo/Makefile \
examples/dommigrate/Makefile \
+ examples/domtop/Makefile \
examples/openauth/Makefile \
examples/hellolibvirt/Makefile \
examples/systemtap/Makefile \
diff --git a/examples/domtop/Makefile.am b/examples/domtop/Makefile.am
new file mode 100644
index 0000000..c5cb6c7
--- /dev/null
+++ b/examples/domtop/Makefile.am
@@ -0,0 +1,27 @@
+## Process this file with automake to produce Makefile.in
+
+## Copyright (C) 2014 Red Hat, Inc.
+##
+## This library is free software; you can redistribute it and/or
+## modify it under the terms of the GNU Lesser General Public
+## License as published by the Free Software Foundation; either
+## version 2.1 of the License, or (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public
+## License along with this library. If not, see
+## <http://www.gnu.org/licenses/>.
+
+INCLUDES = -I$(top_builddir)/include -I$(top_srcdir)/include
+LDADDS = $(STATIC_BINARIES) $(WARN_CFLAGS) $(top_builddir)/src/libvirt.la \
+ $(COVERAGE_LDFLAGS)
+
+noinst_PROGRAMS=domtop
+
+domtop_SOURCES=domtop.c
+domtop_LDFLAGS=
+domtop_LDADD= $(LDADDS)
diff --git a/examples/domtop/domtop.c b/examples/domtop/domtop.c
new file mode 100644
index 0000000..6fb6cbe
--- /dev/null
+++ b/examples/domtop/domtop.c
@@ -0,0 +1,400 @@
+/*
+ * domtop.c: Demo program showing how to calculate CPU usage
+ *
+ * Copyright (C) 2014 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Michal Privoznik <mprivozn at redhat.com>
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <libvirt/libvirt.h>
+#include <libvirt/virterror.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+static bool debug;
+static bool run_top;
+
+#define ERROR(...) \
+do { \
+ fprintf(stderr, "ERROR %s:%d : ", __FUNCTION__, __LINE__); \
+ fprintf(stderr, __VA_ARGS__); \
+ fprintf(stderr, "\n"); \
+} while (0)
+
+#define DEBUG(...) \
+do { \
+ if (!debug) \
+ break; \
+ fprintf(stderr, "DEBUG %s:%d : ", __FUNCTION__, __LINE__); \
+ fprintf(stderr, __VA_ARGS__); \
+ fprintf(stderr, "\n"); \
+} while (0)
+
+#define STREQ(a,b) (strcmp(a,b) == 0)
+
+static void
+print_usage(const char *progname)
+{
+ const char *unified_progname;
+
+ if (!(unified_progname = strrchr(progname, '/')))
+ unified_progname = progname;
+ else
+ unified_progname++;
+
+ printf("\n%s [options] [domain name]\n\n"
+ " options:\n"
+ " -d | --debug enable debug messages\n"
+ " -h | --help print this help\n"
+ " -c | --connect=URI hypervisor connection URI\n"
+ " -D | --delay=X delay between updates in milliseconds\n"
+ "\n"
+ "Print the cumulative usage of each host CPU. \n"
+ "Without any domain name specified the list of \n"
+ "all running domains is printed out.\n",
+ unified_progname);
+}
+
+static int
+parse_argv(int argc, char *argv[],
+ const char **uri,
+ const char **dom_name,
+ unsigned int *milliseconds)
+{
+ int ret = -1;
+ int arg;
+ unsigned long val;
+ char *p;
+ struct option opt[] = {
+ {"debug", no_argument, NULL, 'd'},
+ {"help", no_argument, NULL, 'h'},
+ {"connect", required_argument, NULL, 'c'},
+ {"delay", required_argument, NULL, 'D'},
+ {NULL, 0, NULL, 0}
+ };
+
+ while ((arg = getopt_long(argc, argv, "+:dhc:D:", opt, NULL)) != -1) {
+ switch (arg) {
+ case 'd':
+ debug = true;
+ break;
+ case 'h':
+ print_usage(argv[0]);
+ exit(EXIT_SUCCESS);
+ break;
+ case 'c':
+ *uri = optarg;
+ break;
+ case 'D':
+ /* strtoul man page suggest clearing errno prior to call */
+ errno = 0;
+ val = strtoul(optarg, &p, 10);
+ if (errno || *p || p == optarg) {
+ ERROR("Invalid number: '%s'", optarg);
+ goto cleanup;
+ }
+ *milliseconds = val;
+ if (*milliseconds != val) {
+ ERROR("Integer overflow: %ld", val);
+ goto cleanup;
+ }
+ break;
+ case ':':
+ ERROR("option '-%c' requires an argument", optopt);
+ exit(EXIT_FAILURE);
+ case '?':
+ if (optopt)
+ ERROR("unsupported option '-%c'. See --help.", optopt);
+ else
+ ERROR("unsupported option '%s'. See --help.", argv[optind - 1]);
+ exit(EXIT_FAILURE);
+ default:
+ ERROR("unknown option");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ if (argc > optind)
+ *dom_name = argv[optind];
+
+ ret = 0;
+ cleanup:
+ return ret;
+}
+
+static int
+fetch_domains(virConnectPtr conn)
+{
+ int num_domains, ret = -1;
+ virDomainPtr *domains = NULL;
+ size_t i;
+ const int list_flags = VIR_CONNECT_LIST_DOMAINS_ACTIVE;
+
+ DEBUG("Fetching list of running domains");
+ num_domains = virConnectListAllDomains(conn, &domains, list_flags);
+
+ DEBUG("num_domains=%d", num_domains);
+ if (num_domains < 0) {
+ ERROR("Unable to fetch list of running domains");
+ goto cleanup;
+ }
+
+ printf("Running domains:\n");
+ printf("----------------\n");
+ for (i = 0; i < num_domains; i++) {
+ virDomainPtr dom = domains[i];
+ const char *dom_name = virDomainGetName(dom);
+ printf("%s\n", dom_name);
+ virDomainFree(dom);
+ }
+
+ ret = 0;
+ cleanup:
+ free(domains);
+ return ret;
+}
+
+static void
+print_cpu_usage(const char *dom_name,
+ size_t cpu,
+ size_t ncpus,
+ unsigned long long then,
+ virTypedParameterPtr then_params,
+ size_t then_nparams,
+ unsigned long long now,
+ virTypedParameterPtr now_params,
+ size_t now_nparams)
+{
+ size_t i, j, k;
+ size_t nparams = now_nparams;
+ bool delim = false;
+
+ if (then_nparams != now_nparams) {
+ /* this should not happen (TM) */
+ ERROR("parameters counts don't match");
+ return;
+ }
+
+ for (i = 0; i < ncpus; i++) {
+ size_t pos;
+ double usage;
+
+ /* check if the vCPU is in the maps */
+ if (now_params[i * nparams].type == 0 ||
+ then_params[i * then_nparams].type == 0)
+ continue;
+
+ for (j = 0; j < nparams; j++) {
+ pos = i * nparams + j;
+ if (STREQ(then_params[pos].field, VIR_DOMAIN_CPU_STATS_CPUTIME) ||
+ STREQ(then_params[pos].field, VIR_DOMAIN_CPU_STATS_VCPUTIME))
+ break;
+ }
+
+ if (j == nparams) {
+ ERROR("unable to find %s", VIR_DOMAIN_CPU_STATS_CPUTIME);
+ return;
+ }
+
+ DEBUG("now_params=%llu then_params=%llu now=%llu then=%llu",
+ now_params[pos].value.ul, then_params[pos].value.ul, now, then);
+
+ /* @now_params and @then_params are in nanoseconds, @now and @then are
+ * in microseconds. In ideal world, we would translate them both into
+ * the same scale, divide one by another and multiply by factor of 100
+ * to get percentage. However, the count of floating point operations
+ * performed has a bad effect on the precision, so instead of dividing
+ * @now_params and @then_params by 1000 and then multiplying again by
+ * 100, we divide only once by 10 and get the same result. */
+ usage = (now_params[pos].value.ul - then_params[pos].value.ul) /
+ (now - then) / 10;
+
+ if (delim)
+ printf("\t");
+ printf("CPU%zu: %.2lf", cpu + i, usage);
+ delim = true;
+ }
+
+ if (delim)
+ printf("\n");
+
+}
+
+static void
+stop(int sig)
+{
+ DEBUG("Exiting on signal %d\n", sig);
+ run_top = false;
+}
+
+static int
+do_top(virConnectPtr conn,
+ const char *dom_name,
+ unsigned int milliseconds)
+{
+ int ret = -1;
+ virDomainPtr dom;
+ int max_id;
+ int nparams = 0, then_nparams = 0, now_nparams = 0;
+ virTypedParameterPtr then_params = NULL, now_params = NULL;
+ struct sigaction action_stop;
+
+ memset(&action_stop, 0, sizeof(action_stop));
+ action_stop.sa_handler = stop;
+
+ /* Lookup the domain */
+ if (!(dom = virDomainLookupByName(conn, dom_name))) {
+ ERROR("Unable to find domain '%s'", dom_name);
+ goto cleanup;
+ }
+
+ /* and see how many vCPUs can we fetch stats for */
+ if ((max_id = virDomainGetCPUStats(dom, NULL, 0, 0, 0, 0)) < 0) {
+ ERROR("Unable to get cpu stats");
+ goto cleanup;
+ }
+
+ /* how many stats can we get for a vCPU? */
+ if ((nparams = virDomainGetCPUStats(dom, NULL, 0, 0, 1, 0)) < 0) {
+ ERROR("Unable to get cpu stats");
+ goto cleanup;
+ }
+
+ if (!(now_params = calloc(nparams * max_id, sizeof(*now_params))) ||
+ !(then_params = calloc(nparams * max_id, sizeof(*then_params)))) {
+ ERROR("Unable to allocate memory");
+ goto cleanup;
+ }
+
+ sigaction(SIGTERM, &action_stop, NULL);
+ sigaction(SIGINT, &action_stop, NULL);
+
+ run_top = true;
+ while (run_top) {
+ struct timeval then, now;
+
+ /* Get current time */
+ if (gettimeofday(&then, NULL) < 0) {
+ ERROR("unable to get time");
+ goto cleanup;
+ }
+
+ /* And current stats */
+ if ((then_nparams = virDomainGetCPUStats(dom, then_params,
+ nparams, 0, max_id, 0)) < 0) {
+ ERROR("Unable to get cpu stats");
+ goto cleanup;
+ }
+
+ /* Now sleep some time */
+ usleep(milliseconds * 1000); /* usleep expects microseconds */
+
+ /* And get current time */
+ if (gettimeofday(&now, NULL) < 0) {
+ ERROR("unable to get time");
+ goto cleanup;
+ }
+
+ /* And current stats */
+ if ((now_nparams = virDomainGetCPUStats(dom, now_params,
+ nparams, 0, max_id, 0)) < 0) {
+ ERROR("Unable to get cpu stats");
+ goto cleanup;
+ }
+
+ print_cpu_usage(dom_name, 0, max_id,
+ then.tv_sec * 1000000 + then.tv_usec,
+ then_params, then_nparams,
+ now.tv_sec * 1000000 + now.tv_usec,
+ now_params, now_nparams);
+
+ virTypedParamsClear(now_params, now_nparams * max_id);
+ virTypedParamsClear(then_params, then_nparams * max_id);
+ }
+
+ ret = 0;
+ cleanup:
+ if (max_id > 0) {
+ if (now_nparams > 0)
+ virTypedParamsFree(now_params, now_nparams * max_id);
+ if (then_nparams > 0)
+ virTypedParamsFree(then_params, then_nparams * max_id);
+ }
+ if (dom)
+ virDomainFree(dom);
+ return ret;
+}
+
+int
+main(int argc, char *argv[])
+{
+ int ret = EXIT_FAILURE;
+ virConnectPtr conn = NULL;
+ const char *uri = NULL;
+ const char *dom_name = NULL;
+ unsigned int milliseconds = 500; /* Sleep this long between two API calls */
+ const int connect_flags = 0; /* No connect flags for now */
+
+ if (parse_argv(argc, argv, &uri, &dom_name, &milliseconds) < 0)
+ goto cleanup;
+
+ DEBUG("Proceeding with uri=%s dom_name=%s milliseconds=%u",
+ uri, dom_name, milliseconds);
+
+ if (!(conn = virConnectOpenAuth(uri,
+ virConnectAuthPtrDefault,
+ connect_flags))) {
+ ERROR("Failed to connect to hypervisor");
+ goto cleanup;
+ }
+
+ DEBUG("Successfully connected");
+
+ if (!dom_name) {
+ if (fetch_domains(conn) == 0)
+ ret = EXIT_SUCCESS;
+ goto cleanup;
+ }
+
+ if (do_top(conn, dom_name, milliseconds) < 0)
+ goto cleanup;
+
+ ret = EXIT_SUCCESS;
+ cleanup:
+ if (conn) {
+ int tmp;
+ tmp = virConnectClose(conn);
+ if (tmp < 0) {
+ ERROR("Failed to disconnect from the hypervisor");
+ ret = EXIT_FAILURE;
+ } else if (tmp > 0) {
+ ERROR("One or more references were leaked after "
+ "disconnect from the hypervisor");
+ ret = EXIT_FAILURE;
+ } else {
+ DEBUG("Connection successfully closed");
+ }
+ }
+ return ret;
+}
diff --git a/libvirt.spec.in b/libvirt.spec.in
index 472fa4b..76e57aa 100644
--- a/libvirt.spec.in
+++ b/libvirt.spec.in
@@ -1505,7 +1505,7 @@ rm -fr %{buildroot}
# on RHEL 5, thus we need to expand it here.
make install DESTDIR=%{?buildroot} SYSTEMD_UNIT_DIR=%{_unitdir}
-for i in object-events dominfo domsuspend hellolibvirt openauth xml/nwfilter systemtap dommigrate
+for i in object-events dominfo domsuspend hellolibvirt openauth xml/nwfilter systemtap dommigrate domtop
do
(cd examples/$i ; make clean ; rm -rf .deps .libs Makefile Makefile.in)
done
--
1.8.5.5
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