[libvirt] [PATCH v3 0/2] qemu: add debug-threads support
QEMU (somewhere around 2.0) added a new sub-option to the -name flag -name debug-threads=on This causes the naming of individual QEMU threads to be helpful; e.g. 'CPU/KVM 0' or 'migration' these show up in top once the H key is pressed, and also show up in a core dump, making it easy to figure out which thread is which. The following 2 patches add a capability check and enable debug-threads if supported. Related to: https://bugzilla.redhat.com/show_bug.cgi?id=1140121 cheers v2->v3: - move -name command generation in seperate function - fix syntax-check - fix leak v1->v2: - drop the configuration, enable debug-thread automatically Marc-André Lureau (2): qemu: check for debug-threads capability qemu: enable debug threads src/qemu/qemu_capabilities.c | 2 ++ src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_command.c | 40 ++++++++++++++++++++++------ tests/qemucapabilitiesdata/caps_2.1.1-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.4.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.5.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.6.0-1.caps | 1 + 7 files changed, 39 insertions(+), 8 deletions(-) -- 2.5.0
From: Marc-André Lureau <marcandre.lureau@gmail.com> QEMU (somewhere around 2.0) added a new sub-option to the -name flag -name debug-threads=on. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- src/qemu/qemu_capabilities.c | 2 ++ src/qemu/qemu_capabilities.h | 1 + tests/qemucapabilitiesdata/caps_2.1.1-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.4.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.5.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.6.0-1.caps | 1 + 6 files changed, 7 insertions(+) diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index fce79f8..403d872 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -320,6 +320,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST, "qxl-vga.vram64_size_mb", /* 215 */ "chardev-logfile", + "debug-threads", ); @@ -2636,6 +2637,7 @@ static struct virQEMUCapsCommandLineProps virQEMUCapsCommandLine[] = { { "chardev", "append", QEMU_CAPS_CHARDEV_FILE_APPEND }, { "spice", "gl", QEMU_CAPS_SPICE_GL }, { "chardev", "logfile", QEMU_CAPS_CHARDEV_LOGFILE }, + { "name", "debug-threads", QEMU_CAPS_NAME_DEBUG_THREADS }, }; static int diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h index af8d15b..01ceb8e 100644 --- a/src/qemu/qemu_capabilities.h +++ b/src/qemu/qemu_capabilities.h @@ -350,6 +350,7 @@ typedef enum { /* 215 */ QEMU_CAPS_QXL_VGA_VRAM64, /* -device qxl-vga.vram64_size_mb */ QEMU_CAPS_CHARDEV_LOGFILE, /* -chardev logfile=xxxx */ + QEMU_CAPS_NAME_DEBUG_THREADS, /* Is -name debug-threads= available */ QEMU_CAPS_LAST /* this must always be the last item */ } virQEMUCapsFlags; diff --git a/tests/qemucapabilitiesdata/caps_2.1.1-1.caps b/tests/qemucapabilitiesdata/caps_2.1.1-1.caps index fd2639d..59d0323 100644 --- a/tests/qemucapabilitiesdata/caps_2.1.1-1.caps +++ b/tests/qemucapabilitiesdata/caps_2.1.1-1.caps @@ -162,4 +162,5 @@ <flag name='vserport-change-event'/> <flag name='qxl.vram64_size_mb'/> <flag name='qxl-vga.vram64_size_mb'/> + <flag name='debug-threads'/> </qemuCaps> diff --git a/tests/qemucapabilitiesdata/caps_2.4.0-1.caps b/tests/qemucapabilitiesdata/caps_2.4.0-1.caps index 4b61fc1..efbf9af 100644 --- a/tests/qemucapabilitiesdata/caps_2.4.0-1.caps +++ b/tests/qemucapabilitiesdata/caps_2.4.0-1.caps @@ -173,4 +173,5 @@ <flag name='virtio-balloon-pci.deflate-on-oom'/> <flag name='qxl.vram64_size_mb'/> <flag name='qxl-vga.vram64_size_mb'/> + <flag name='debug-threads'/> </qemuCaps> diff --git a/tests/qemucapabilitiesdata/caps_2.5.0-1.caps b/tests/qemucapabilitiesdata/caps_2.5.0-1.caps index 2061d0e..5fd3bce 100644 --- a/tests/qemucapabilitiesdata/caps_2.5.0-1.caps +++ b/tests/qemucapabilitiesdata/caps_2.5.0-1.caps @@ -174,4 +174,5 @@ <flag name='virtio-balloon-pci.deflate-on-oom'/> <flag name='qxl.vram64_size_mb'/> <flag name='qxl-vga.vram64_size_mb'/> + <flag name='debug-threads'/> </qemuCaps> diff --git a/tests/qemucapabilitiesdata/caps_2.6.0-1.caps b/tests/qemucapabilitiesdata/caps_2.6.0-1.caps index 8374cda..549759c 100644 --- a/tests/qemucapabilitiesdata/caps_2.6.0-1.caps +++ b/tests/qemucapabilitiesdata/caps_2.6.0-1.caps @@ -177,4 +177,5 @@ <flag name='spice-gl'/> <flag name='qxl.vram64_size_mb'/> <flag name='qxl-vga.vram64_size_mb'/> + <flag name='debug-threads'/> </qemuCaps> -- 2.5.0
On Thu, Mar 10, 2016 at 19:31:55 +0100, Marc-André Lureau wrote:
From: Marc-André Lureau <marcandre.lureau@gmail.com>
QEMU (somewhere around 2.0) added a new sub-option to the -name flag -name debug-threads=on.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- src/qemu/qemu_capabilities.c | 2 ++ src/qemu/qemu_capabilities.h | 1 + tests/qemucapabilitiesdata/caps_2.1.1-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.4.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.5.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.6.0-1.caps | 1 + 6 files changed, 7 insertions(+)
ACK Jirka
When debug-threads is enabled, individual threads are given a separate name (on Linux) Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1140121 Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- src/qemu/qemu_command.c | 40 ++++++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index ee06479..96be9e1 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -5333,6 +5333,36 @@ qemuAppendKeyWrapMachineParms(virBuffer *buf, virQEMUCapsPtr qemuCaps, } static int +qemuBuildNameCommandLine(virCommandPtr cmd, + virQEMUDriverConfigPtr cfg, + const virDomainDef *def, + virQEMUCapsPtr qemuCaps) +{ + virBuffer buf = VIR_BUFFER_INITIALIZER; + char *name_args; + + virCommandAddArg(cmd, "-name"); + + virBufferAsprintf(&buf, "%s", def->name); + + if (cfg->setProcessName && + virQEMUCapsGet(qemuCaps, QEMU_CAPS_NAME_PROCESS)) + virBufferAsprintf(&buf, ",process=qemu:%s", def->name); + + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NAME_DEBUG_THREADS)) + virBufferAddLit(&buf, ",debug-threads=on"); + + if (virBufferCheckError(&buf) < 0) + return -1; + + name_args = virBufferContentAndReset(&buf); + virCommandAddArg(cmd, name_args); + VIR_FREE(name_args); + + return 0; +} + +static int qemuBuildMachineCommandLine(virCommandPtr cmd, const virDomainDef *def, virQEMUCapsPtr qemuCaps) @@ -7192,14 +7222,8 @@ qemuBuildCommandLine(virConnectPtr conn, virCommandAddEnvPassCommon(cmd); - virCommandAddArg(cmd, "-name"); - if (cfg->setProcessName && - virQEMUCapsGet(qemuCaps, QEMU_CAPS_NAME_PROCESS)) { - virCommandAddArgFormat(cmd, "%s,process=qemu:%s", - def->name, def->name); - } else { - virCommandAddArg(cmd, def->name); - } + if (qemuBuildNameCommandLine(cmd, cfg, def, qemuCaps) < 0) + goto error; if (!standalone) virCommandAddArg(cmd, "-S"); /* freeze CPU */ -- 2.5.0
On Thu, Mar 10, 2016 at 19:31:56 +0100, Marc-André Lureau wrote:
When debug-threads is enabled, individual threads are given a separate name (on Linux)
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1140121
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- src/qemu/qemu_command.c | 40 ++++++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index ee06479..96be9e1 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -5333,6 +5333,36 @@ qemuAppendKeyWrapMachineParms(virBuffer *buf, virQEMUCapsPtr qemuCaps, }
static int +qemuBuildNameCommandLine(virCommandPtr cmd, + virQEMUDriverConfigPtr cfg, + const virDomainDef *def, + virQEMUCapsPtr qemuCaps) +{ + virBuffer buf = VIR_BUFFER_INITIALIZER; + char *name_args;
The name_args variable is not necessary since...
+ + virCommandAddArg(cmd, "-name"); + + virBufferAsprintf(&buf, "%s", def->name); + + if (cfg->setProcessName && + virQEMUCapsGet(qemuCaps, QEMU_CAPS_NAME_PROCESS)) + virBufferAsprintf(&buf, ",process=qemu:%s", def->name); + + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NAME_DEBUG_THREADS)) + virBufferAddLit(&buf, ",debug-threads=on"); +
you can simplify the following code
+ if (virBufferCheckError(&buf) < 0) + return -1; + + name_args = virBufferContentAndReset(&buf); + virCommandAddArg(cmd, name_args); + VIR_FREE(name_args);
to just virCommandAddArgBuffer(cmd, &buf);
+ + return 0; +}
ACK with that tweak. Jirka
On 03/10/2016 01:31 PM, Marc-André Lureau wrote:
QEMU (somewhere around 2.0) added a new sub-option to the -name flag -name debug-threads=on
This causes the naming of individual QEMU threads to be helpful; e.g. 'CPU/KVM 0' or 'migration' these show up in top once the H key is pressed, and also show up in a core dump, making it easy to figure out which thread is which.
The following 2 patches add a capability check and enable debug-threads if supported.
Related to: https://bugzilla.redhat.com/show_bug.cgi?id=1140121
cheers
v2->v3: - move -name command generation in seperate function - fix syntax-check - fix leak
v1->v2: - drop the configuration, enable debug-thread automatically
Marc-André Lureau (2): qemu: check for debug-threads capability qemu: enable debug threads
src/qemu/qemu_capabilities.c | 2 ++ src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_command.c | 40 ++++++++++++++++++++++------ tests/qemucapabilitiesdata/caps_2.1.1-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.4.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.5.0-1.caps | 1 + tests/qemucapabilitiesdata/caps_2.6.0-1.caps | 1 + 7 files changed, 39 insertions(+), 8 deletions(-)
Also needs a test case for argv generation... qemuxml2argv is the best place even though it's not XML specific - Cole
participants (3)
-
Cole Robinson -
Jiri Denemark -
Marc-André Lureau