On Thu, Jan 24, 2013 at 02:59:49PM -0500, Laine Stump wrote:
On 01/24/2013 01:34 PM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange@redhat.com>
This previous commit
commit 1a50ba2cb07d8bb2aa724062889deb9efd7ad9e9 Author: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> Date: Mon Nov 26 15:17:13 2012 +0100
qemu: Fix QMP Capabability Probing Failure
which attempted to make sure the QEMU process used for probing ran as the right user id, caused serious performance regression and unreliability in probing. The -daemonize switch in QEMU guarantees that the monitor socket is present before the parent process exits. This means libvirtd is guaranteed to be able to connect immediately. By switching from -daemonize to the virCommandDaemonize API libvirtd was no longer synchronized with QEMU's startup process. The result was that the QEMU monitor failed to open and went into its 200ms sleep loop. This happened for all 25 binaries resulting in 5 seconds worth of sleeping at libvirtd startup. In addition sometimes when libvirt connected, QEMU would be partially initialized and crash causing total failure to probe that binary.
This commit reverts the previous change, ensuring we do use the -daemonize flag to QEMU. Startup delay is cut from 7 seconds to 2 seconds on my machine, which is on a par with what it was prior to the capabilities rewrite.
To deal with the fact that QEMU needs to be able to create the pidfile, we switch pidfile location fron runDir to libDir, which QEMU is guaranteed to be able to write to.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- src/qemu/qemu_capabilities.c | 50 ++++++++++++++++++++++++++++++-------------- src/qemu/qemu_capabilities.h | 3 +-- 2 files changed, 35 insertions(+), 18 deletions(-)
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index 95fa3da..703179d 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -38,6 +38,7 @@ #include "virbitmap.h" #include "virnodesuspend.h" #include "qemu_monitor.h" +#include "virtime.h"
#include <sys/stat.h> #include <unistd.h> @@ -916,11 +917,19 @@ virCapsPtr qemuCapsInit(qemuCapsCachePtr cache) * so just probe for them all - we gracefully fail * if a qemu-system-$ARCH binary can't be found */ - for (i = 0 ; i < VIR_ARCH_LAST ; i++) + unsigned long long a, b; + for (i = 0 ; i < VIR_ARCH_LAST ; i++) { + unsigned long long start, end; + if (virTimeMillisNow(&start) < 0) + goto error; if (qemuCapsInitGuest(caps, cache, virArchFromHost(), i) < 0) goto error; + if (virTimeMillisNow(&end) < 0) + goto error; + VIR_DEBUG("Probed %s in %llums", virArchToString(i), end-start); + }
Did you intend to leave in this debug code? (if you did, you need to move the definition of a & b up to the top of the block, and maybe rename them to something more descriptive)
No, it should have been removed. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|