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From: Scott Cheloha <cheloha@linux.vnet.ibm.com>
To: qemu-devel@nongnu.org
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	Juan Quintela <quintela@redhat.com>
Subject: [PATCH v2 0/2] migration: faster savevm_state_handler_insert()
Date: Thu, 17 Oct 2019 15:59:51 -0500
Message-ID: <20191017205953.13122-1-cheloha@linux.vnet.ibm.com> (raw)

The savevm_state.handlers queue of SaveStateEntry objects is a
priority queue with an O(n) insertion cost.  This is makes startup
extremely slow when a VM has many such objects to register.  For
instance, a ppc64 VM with a large (8T+) maxmem needs to register tens
of thousands of SaveStateEntry handlers: startup for these VMs is

If we track insertion points within the priority queue we can make
savevm_state_handler_insert() a constant-time operation with little
change to the module's code.  Startup times for VMs with many handlers
are dramatically improved as a result.

Changes since v1:
  * Split patch 1 into 2 patches.

Scott Cheloha (2):
  migration: add savevm_state_handler_remove()
  migration: savevm_state_handler_insert: constant-time element

 migration/savevm.c | 35 ++++++++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)


             reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-17 20:59 Scott Cheloha [this message]
2019-10-17 20:59 ` [PATCH v2 1/2] migration: add savevm_state_handler_remove() Scott Cheloha
2019-12-04 16:43   ` Dr. David Alan Gilbert
2020-01-08 19:07   ` Juan Quintela
2019-10-17 20:59 ` [PATCH v2 2/2] migration: savevm_state_handler_insert: constant-time element insertion Scott Cheloha
2019-10-18  8:16   ` Dr. David Alan Gilbert
2019-10-18  8:34     ` Laurent Vivier
2019-10-18  9:43       ` Dr. David Alan Gilbert
2019-10-18 16:38         ` Michael Roth
2019-10-18 17:26           ` Dr. David Alan Gilbert
2019-10-21  7:33           ` David Gibson
2019-10-19 10:12         ` David Gibson
2019-10-21  8:14           ` Dr. David Alan Gilbert
2019-11-20 21:48             ` Scott Cheloha
2019-12-04 16:49               ` Dr. David Alan Gilbert
2019-12-04 22:28                 ` David Gibson
2019-12-04 16:47   ` Dr. David Alan Gilbert

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