From c290fa1c4b7b280a26cbf742ab109fa2db2d10a3 Mon Sep 17 00:00:00 2001 From: "\"Dube, Lutz\"" Date: Fri, 23 Jul 2010 17:34:35 +0100 Subject: tools/xend: Fix performance of xend with more than 10000 FC device paths On server startup xend start or a later xend restart needs approx. 30 min to start/restart. Without attached FC devices xend start/restart needs only some seconds. server type: Fujitsu Primergy RX600-S5 The time gets lost in xen/xend/XendNode.py line 329 while calling vscsi_util.get_all_scsi_device(). 329 for pscsi_record in vscsi_util.get_all_scsi_devices(): 330 scsi_id = pscsi_record['scsi_id'] 331 if scsi_id: 332 saved_HBA_uuid = None I think, in most cases we don't need all the PSCSI devices registered in xend, but only a few of it. So a good solution for this perforamce issue is to scan only the SCSI device paths we need, controlled by a new option in xend-config.sxp. I have made a patch to allow specification of scsi devices we need in xend in the config file xend-config.sxp. The new options pscsi-device-mask expects a list of device ids oder partial device ids like the option of lsscsi, e.g. (pscsi-device-mask (': "Well done" Committed-by: Ian Jackson --- tools/examples/xend-config.sxp | 8 ++++++++ tools/python/xen/util/vscsi_util.py | 11 ++++++----- tools/python/xen/xend/XendNode.py | 7 ++++++- tools/python/xen/xend/XendOptions.py | 7 +++++++ 4 files changed, 27 insertions(+), 6 deletions(-) (limited to 'tools') diff --git a/tools/examples/xend-config.sxp b/tools/examples/xend-config.sxp index b7e98f464d..0896a27645 100644 --- a/tools/examples/xend-config.sxp +++ b/tools/examples/xend-config.sxp @@ -294,3 +294,11 @@ # we have to realize this may incur security issue and we can't make sure the # device assignment could really work properly even after we do this. #(pci-passthrough-strict-check yes) + +# If we have a very big scsi device configuration, start of xend is slow, +# because xend scans all the device paths to build its internal PSCSI device +# list. If we need only a few devices for assigning to a guest, we can reduce +# the scan to this device. Set list list of device paths in same syntax like in +# command lsscsi, e.g. ('16:0:0:0' '15:0') +# (pscsi-device-mask ('*')) + diff --git a/tools/python/xen/util/vscsi_util.py b/tools/python/xen/util/vscsi_util.py index 15719782fa..8d5351f4fd 100644 --- a/tools/python/xen/util/vscsi_util.py +++ b/tools/python/xen/util/vscsi_util.py @@ -148,11 +148,12 @@ def _vscsi_get_scsidevices_by_sysfs(): return devices -def vscsi_get_scsidevices(): +def vscsi_get_scsidevices(mask=""): """ get all scsi devices information """ - devices = _vscsi_get_scsidevices_by_lsscsi("") - if devices: + devices = _vscsi_get_scsidevices_by_lsscsi("[%s]" % mask) + if devices or (len(mask) and mask[0] != "*"): + # devices found or partial device scan return devices return _vscsi_get_scsidevices_by_sysfs() @@ -274,9 +275,9 @@ def get_scsi_device(pHCTL): return _make_scsi_record(scsi_info) return None -def get_all_scsi_devices(): +def get_all_scsi_devices(mask=""): scsi_records = [] - for scsi_info in vscsi_get_scsidevices(): + for scsi_info in vscsi_get_scsidevices(mask): scsi_record = _make_scsi_record(scsi_info) scsi_records.append(scsi_record) return scsi_records diff --git a/tools/python/xen/xend/XendNode.py b/tools/python/xen/xend/XendNode.py index 25986102ff..f16932ceda 100644 --- a/tools/python/xen/xend/XendNode.py +++ b/tools/python/xen/xend/XendNode.py @@ -326,7 +326,12 @@ class XendNode: pscsi_table = {} pscsi_HBA_table = {} - for pscsi_record in vscsi_util.get_all_scsi_devices(): + pscsi_records = [] + for pscsi_mask in xendoptions().get_pscsi_device_mask(): + pscsi_records += vscsi_util.get_all_scsi_devices(pscsi_mask) + log.debug("pscsi record count: %s" % len(pscsi_records)) + + for pscsi_record in pscsi_records: scsi_id = pscsi_record['scsi_id'] if scsi_id: saved_HBA_uuid = None diff --git a/tools/python/xen/xend/XendOptions.py b/tools/python/xen/xend/XendOptions.py index 9abe9b1c2a..01287f7263 100644 --- a/tools/python/xen/xend/XendOptions.py +++ b/tools/python/xen/xend/XendOptions.py @@ -164,6 +164,9 @@ class XendOptions: """ print >>sys.stderr, "xend [ERROR]", fmt % args + """Default mask for pscsi device scan.""" + xend_pscsi_device_mask = ['*'] + def configure(self): self.set_config() @@ -430,6 +433,10 @@ class XendOptions: return self.get_config_bool("pci-passthrough-strict-check", self.pci_dev_assign_strict_check_default) + def get_pscsi_device_mask(self): + return self.get_config_value("pscsi-device-mask", + self.xend_pscsi_device_mask) + class XendOptionsFile(XendOptions): """Default path to the config file.""" -- cgit v1.2.3