On Mon, Mar 10, 2014 at 12:50:20PM -0600, Eric Blake wrote:
On 03/10/2014 10:54 AM, Daniel P. Berrange wrote:
Extracting capabilities from QEMU takes a notable amount of time when all QEMU binaries are installed. Each system emulator needs about 200-300ms multiplied by 26 binaries == ~5-8 seconds.
This change causes the QEMU driver to save an XML file containing the content of the virQEMUCaps object instance in the cache dir eg /var/cache/libvirt/qemu/capabilities/$SHA256(binarypath).xml or $HOME/.cache/libvirt/qemu/cache/capabilities/$SHA256(binarypath).xml
+ */ +static int +virQEMUCapsLoadCache(virQEMUCapsPtr qemuCaps, const char *filename, + time_t *qemuctime, time_t *selfctime) +{
+ if (virXPathLongLong("string(./qemuctime)", ctxt, &l) < 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("missing qemuctime in QEMU capabilities XML"));
+ qemuCaps->usedQMP = virXPathBoolean("count(.//usedQMP) > 0",
Why ./qemuctime but .//usedQMP? What difference does // make in XPath?
That's a bug, but thanks to xpath it just happens to still work. ./foo means match '<foo>' as an immediate child of current node. .//foo means match '<foo>' as an arbitrarily deep child of the current node.
+static int +virQEMUCapsSaveCache(virQEMUCapsPtr qemuCaps, const char *filename) +{ + virBuffer buf = VIR_BUFFER_INITIALIZER; + const char *xml = NULL; + int ret = -1; + size_t i; + + virBufferAddLit(&buf, "<qemuCaps>\n"); + + virBufferAsprintf(&buf, " <qemuctime>%llu</qemuctime>\n",
Conflicts with Laine's work to require virBufferAddIndent() rather than hard-coding indentation. Will be interesting to see who gets in first :)
Well it doesn't conflict so much as mean Laine has more work todo :-P
+static void +virQEMUCapsReset(virQEMUCapsPtr qemuCaps) +{ + size_t i; + + virBitmapClearAll(qemuCaps->flags); + qemuCaps->version = qemuCaps->kvmVersion = 0; + qemuCaps->arch = VIR_ARCH_NONE;
Shouldn't you also reset qemuCaps->usedQMP and qemuCaps->ctime, to get the struct back to a known-default state? Or is this only ever going to be used just before freeing the struct, at which point all the reset-to-0 code is wasted CPU cycles?
It should reset usedQMP, but not ctime - the ctime value always matches the current QEMU binary and we don't overwrite that when loading the XML. Regards, 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 :|