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From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: linux-ia64@vger.kernel.org
Subject: RE: ia64 get_mmu_context patch
Date: Fri, 28 Oct 2005 18:40:40 +0000	[thread overview]
Message-ID: <200510281840.j9SIeeg23727@unix-os.sc.intel.com> (raw)
In-Reply-To: <200510271728.j9RHScS0002221922@kitche.zk3.dec.com>

I did a crude fork bomb test, then printed out ia64_ctx.next
ia64_ctx.limit and the diff in wrap_mmu_context().  Here is
the result:

First call resulted expected 2M hole.  Look what happens
after first wrap.  My worst fear of global tlb flush after
just one ctx_id allocation is actually happening!  Average
~ 90,000 ctx_id allocation between flush.  Much smaller
than advertised 2^21.  This find_next_hole() is horribly
broken in terms of performance.

- Ken


wrap_mmu_context: next = 32767, limit = 2097152 n = 2064385
wrap_mmu_context: next = 300, limit = 1782 n = 1482
wrap_mmu_context: next = 1783, limit = 1872 n = 89
wrap_mmu_context: next = 1873, limit = 1883 n = 10
wrap_mmu_context: next = 1884, limit = 1921 n = 37
wrap_mmu_context: next = 1922, limit = 1973 n = 51
wrap_mmu_context: next = 1974, limit = 1998 n = 24
wrap_mmu_context: next = 1999, limit = 2055 n = 56
wrap_mmu_context: next = 2056, limit = 2109 n = 53
wrap_mmu_context: next = 2110, limit = 2111 n = 1
wrap_mmu_context: next = 2118, limit = 2124 n = 6
wrap_mmu_context: next = 2125, limit = 2128 n = 3
wrap_mmu_context: next = 2129, limit = 140411 n = 138282
wrap_mmu_context: next = 140412, limit = 518442 n = 378030
wrap_mmu_context: next = 518443, limit = 520789 n = 2346
wrap_mmu_context: next = 520790, limit = 980204 n = 459414
wrap_mmu_context: next = 980205, limit = 1864365 n = 884160
wrap_mmu_context: next = 1864366, limit = 1864528 n = 162
wrap_mmu_context: next = 1864529, limit = 2066917 n = 202388
wrap_mmu_context: next = 2066918, limit = 2097152 n = 30234
wrap_mmu_context: next = 300, limit = 1782 n = 1482
wrap_mmu_context: next = 1783, limit = 1872 n = 89
wrap_mmu_context: next = 1873, limit = 1883 n = 10
wrap_mmu_context: next = 1884, limit = 1921 n = 37
wrap_mmu_context: next = 1922, limit = 1973 n = 51
wrap_mmu_context: next = 1974, limit = 1998 n = 24
wrap_mmu_context: next = 1999, limit = 2055 n = 56
wrap_mmu_context: next = 2056, limit = 2109 n = 53
wrap_mmu_context: next = 2110, limit = 2111 n = 1
wrap_mmu_context: next = 2118, limit = 2124 n = 6
wrap_mmu_context: next = 2125, limit = 2128 n = 3
wrap_mmu_context: next = 2129, limit = 140411 n = 138282
wrap_mmu_context: next = 140412, limit = 184686 n = 44274
wrap_mmu_context: next = 184687, limit = 188664 n = 3977
wrap_mmu_context: next = 188665, limit = 398496 n = 209831
wrap_mmu_context: next = 398497, limit = 492604 n = 94107
wrap_mmu_context: next = 492605, limit = 510747 n = 18142
wrap_mmu_context: next = 510748, limit = 510923 n = 175
wrap_mmu_context: next = 510924, limit = 518442 n = 7518
wrap_mmu_context: next = 518443, limit = 520789 n = 2346
wrap_mmu_context: next = 520790, limit = 980204 n = 459414
wrap_mmu_context: next = 980205, limit = 1864365 n = 884160
wrap_mmu_context: next = 1864366, limit = 1864528 n = 162
wrap_mmu_context: next = 1864529, limit = 2097152 n = 232623
wrap_mmu_context: next = 300, limit = 1782 n = 1482
wrap_mmu_context: next = 1783, limit = 1872 n = 89
wrap_mmu_context: next = 1873, limit = 1883 n = 10
wrap_mmu_context: next = 1884, limit = 1921 n = 37
wrap_mmu_context: next = 1922, limit = 1973 n = 51
wrap_mmu_context: next = 1974, limit = 1998 n = 24
wrap_mmu_context: next = 1999, limit = 2055 n = 56
wrap_mmu_context: next = 2056, limit = 2109 n = 53
wrap_mmu_context: next = 2110, limit = 2111 n = 1
wrap_mmu_context: next = 2118, limit = 2124 n = 6
wrap_mmu_context: next = 2125, limit = 2128 n = 3
wrap_mmu_context: next = 2129, limit = 140411 n = 138282
wrap_mmu_context: next = 140412, limit = 184686 n = 44274
wrap_mmu_context: next = 184687, limit = 188664 n = 3977
wrap_mmu_context: next = 188665, limit = 398496 n = 209831
wrap_mmu_context: next = 398497, limit = 492604 n = 94107
wrap_mmu_context: next = 492605, limit = 510747 n = 18142
wrap_mmu_context: next = 510748, limit = 510923 n = 175
wrap_mmu_context: next = 510924, limit = 518442 n = 7518
wrap_mmu_context: next = 518443, limit = 520789 n = 2346
wrap_mmu_context: next = 520790, limit = 980204 n = 459414
wrap_mmu_context: next = 980205, limit = 1864365 n = 884160
wrap_mmu_context: next = 1864366, limit = 1864528 n = 162
wrap_mmu_context: next = 1864529, limit = 2097152 n = 232623


  parent reply	other threads:[~2005-10-28 18:40 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-27 17:28 ia64 get_mmu_context patch Peter Keilty
2005-10-28  2:54 ` Chen, Kenneth W
2005-10-28  3:09 ` Chen, Kenneth W
2005-10-28  3:23 ` Chen, Kenneth W
2005-10-28 14:49 ` Peter Keilty
2005-10-28 14:50 ` Peter Keilty
2005-10-28 17:56 ` Chen, Kenneth W
2005-10-28 17:59 ` Chen, Kenneth W
2005-10-28 18:06 ` Chen, Kenneth W
2005-10-28 18:40 ` Chen, Kenneth W [this message]
2005-10-28 18:49 ` Peter Keilty

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