Re: [perf-discuss] How to lower sys utlization and reduce xcalls?

[Andrew Gallatin]

Steve Sistare wrote:

This has the same signature as CR:

  6694625 Performance falls off the cliff with large IO sizes
  http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6694625

which was raised in the network forum thread "expensive pullupmsg in
kstrgetmsg()"

  http://www.opensolaris.org/jive/thread.jspa?messageID=229124&#229124

This was fixed in nv_112, so it just missed OpenSolaris 2009.06.

The discussion says that the issue gets worse when the RX socket
buffer size is increased, so you could try reducing it as a workaround.

I'm the one who filed that bug..

You can tell if its this particular bug by using mdb to
set mblk_pull_len to 0 and seeing if that reduces the
xcalls due to dblk_lastfree_oversize

Cheers,

Drew
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