svn commit: r248154 - head/sys/dev/acpica

[Alexander Motin]

Author: mav
Date: Mon Mar 11 12:02:03 2013
New Revision: 248154
URL: http://svnweb.freebsd.org/changeset/base/248154

Log:
  Reduce HPET eventtimer priority on systems with 8 or more cores.  Price of
  the lock congestion may be too high there (2.5% on 4x4 core AMD Opteron).

Modified:
  head/sys/dev/acpica/acpi_hpet.c

Modified: head/sys/dev/acpica/acpi_hpet.c
==============================================================================
--- head/sys/dev/acpica/acpi_hpet.c	Mon Mar 11 10:56:46 2013	(r248153)
+++ head/sys/dev/acpica/acpi_hpet.c	Mon Mar 11 12:02:03 2013	(r248154)
@@ -675,7 +675,8 @@ hpet_attach(device_t dev)
 		if (t->pcpu_master >= 0) {
 			t->et.et_flags |= ET_FLAGS_PERCPU;
 			t->et.et_quality += 100;
-		}
+		} if (mp_ncpus >= 8)
+			t->et.et_quality -= 100;
 		if ((t->caps & HPET_TCAP_PER_INT) == 0)
 			t->et.et_quality -= 10;
 		t->et.et_frequency = sc->freq;