From: Slavomir Kaslev <kaslevs@vmware.com>
To: linux-trace-devel@vger.kernel.org
Cc: rostedt@goodmis.org, slavomir.kaslev@gmail.com,
tstoyanov@vmware.com, ykaradzhov@vmware.com
Subject: [RFC PATCH v5 08/11] trace-cmd: Try to autodetect number of guest CPUs in setup-guest if not specified
Date: Mon, 4 Feb 2019 08:58:45 +0200 [thread overview]
Message-ID: <20190204065848.8248-9-kaslevs@vmware.com> (raw)
In-Reply-To: <20190204065848.8248-1-kaslevs@vmware.com>
When no number of guest CPUs is provided with the -c flag to `trace-cmd
setup-guest`, try to autodetect it using virsh for libvirt managed guests.
Signed-off-by: Slavomir Kaslev <kaslevs@vmware.com>
---
tracecmd/trace-setup-guest.c | 21 +++++++++++++++++++++
tracecmd/trace-usage.c | 2 +-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/tracecmd/trace-setup-guest.c b/tracecmd/trace-setup-guest.c
index 1a2c8d4..bcd8f40 100644
--- a/tracecmd/trace-setup-guest.c
+++ b/tracecmd/trace-setup-guest.c
@@ -100,6 +100,24 @@ static int make_guest_fifos(const char *guest, int nr_cpus, mode_t mode)
return ret;
}
+static int get_guest_cpu_count(const char *guest)
+{
+ const char *cmd_fmt = "virsh vcpucount --maximum '%s' 2>/dev/null";
+ int nr_cpus = -1;
+ char cmd[1024];
+ FILE *f;
+
+ snprintf(cmd, sizeof(cmd), cmd_fmt, guest);
+ f = popen(cmd, "r");
+ if (!f)
+ return -1;
+
+ fscanf(f, "%d", &nr_cpus);
+ pclose(f);
+
+ return nr_cpus;
+}
+
static void do_setup_guest(const char *guest, int nr_cpus, mode_t mode, gid_t gid)
{
gid_t save_egid;
@@ -174,6 +192,9 @@ void trace_setup_guest(int argc, char **argv)
guest = argv[optind+1];
+ if (nr_cpus <= 0)
+ nr_cpus = get_guest_cpu_count(guest);
+
if (nr_cpus <= 0)
pdie("invalid number of cpus for guest %s", guest);
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index 7a8002f..9a13d93 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -249,7 +249,7 @@ static struct usage_help usage_help[] = {
{
"setup-guest",
"create FIFOs for tracing guest VMs",
- " %s setup-guest -c cpus[-p perm][-g group] guest\n"
+ " %s setup-guest [-c cpus][-p perm][-g group] guest\n"
" -c number of guest virtual CPUs\n"
" -p FIFOs permissions (default: 0660)\n"
" -g FIFOs group owner\n"
--
2.19.1
next prev parent reply other threads:[~2019-02-04 6:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 6:58 [RFC PATCH v5 00/11] Add VM kernel tracing over vsockets and FIFOs Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 01/11] trace-cmd: Detect if vsockets are available Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 02/11] trace-cmd: Add tracecmd_create_recorder_virt function Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 03/11] trace-cmd: Add TRACE_REQ and TRACE_RESP messages Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 04/11] trace-cmd: Add buffer instance flags for tracing in guest and agent context Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 05/11] trace-cmd: Add VM kernel tracing over vsockets transport Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 06/11] trace-cmd: Use splice(2) for vsockets if available Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 07/11] trace-cmd: Add `trace-cmd setup-guest` command Slavomir Kaslev
2019-02-04 6:58 ` Slavomir Kaslev [this message]
2019-02-04 6:58 ` [RFC PATCH v5 09/11] trace-cmd: Make setup-guest auto attach FIFOs to the guest VM config Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 10/11] trace-cmd: Set both input and output to non-blocking when recording is stopped Slavomir Kaslev
2019-02-04 6:58 ` [RFC PATCH v5 11/11] trace-cmd: Add VM tracing over FIFOs transport Slavomir Kaslev
2019-02-08 21:03 ` [RFC PATCH v5 00/11] Add VM kernel tracing over vsockets and FIFOs Steven Rostedt
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