From 01a08546af311c065f34727787dd0cc8dc0c216f Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 31 Aug 2010 10:28:16 +0200 Subject: sched: Add book scheduling domain On top of the SMT and MC scheduling domains this adds the BOOK scheduling domain. This is useful for NUMA like machines which do not have an interface which tells which piece of memory is attached to which node or where the hardware performs striping. Signed-off-by: Heiko Carstens Signed-off-by: Peter Zijlstra LKML-Reference: <20100831082844.253053798@de.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/topology.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/topology.h') diff --git a/include/linux/topology.h b/include/linux/topology.h index 64e084ff5e5c..b91a40e847d2 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -201,6 +201,12 @@ int arch_update_cpu_topology(void); .balance_interval = 64, \ } +#ifdef CONFIG_SCHED_BOOK +#ifndef SD_BOOK_INIT +#error Please define an appropriate SD_BOOK_INIT in include/asm/topology.h!!! +#endif +#endif /* CONFIG_SCHED_BOOK */ + #ifdef CONFIG_NUMA #ifndef SD_NODE_INIT #error Please define an appropriate SD_NODE_INIT in include/asm/topology.h!!! -- cgit v1.2.2 From 32e45ff43eaf5c17f5a82c9ad358d515622c2562 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Wed, 15 Jun 2011 15:08:20 -0700 Subject: mm: increase RECLAIM_DISTANCE to 30 Recently, Robert Mueller reported (http://lkml.org/lkml/2010/9/12/236) that zone_reclaim_mode doesn't work properly on his new NUMA server (Dual Xeon E5520 + Intel S5520UR MB). He is using Cyrus IMAPd and it's built on a very traditional single-process model. * a master process which reads config files and manages the other process * multiple imapd processes, one per connection * multiple pop3d processes, one per connection * multiple lmtpd processes, one per connection * periodical "cleanup" processes. There are thousands of independent processes. The problem is, recent Intel motherboard turn on zone_reclaim_mode by default and traditional prefork model software don't work well on it. Unfortunatelly, such models are still typical even in the 21st century. We can't ignore them. This patch raises the zone_reclaim_mode threshold to 30. 30 doesn't have any specific meaning. but 20 means that one-hop QPI/Hypertransport and such relatively cheap 2-4 socket machine are often used for traditional servers as above. The intention is that these machines don't use zone_reclaim_mode. Note: ia64 and Power have arch specific RECLAIM_DISTANCE definitions. This patch doesn't change such high-end NUMA machine behavior. Dave Hansen said: : I know specifically of pieces of x86 hardware that set the information : in the BIOS to '21' *specifically* so they'll get the zone_reclaim_mode : behavior which that implies. : : They've done performance testing and run very large and scary benchmarks : to make sure that they _want_ this turned on. What this means for them : is that they'll probably be de-optimized, at least on newer versions of : the kernel. : : If you want to do this for particular systems, maybe _that_'s what we : should do. Have a list of specific configurations that need the : defaults overridden either because they're buggy, or they have an : unusual hardware configuration not really reflected in the distance : table. And later said: : The original change in the hardware tables was for the benefit of a : benchmark. Said benchmark isn't going to get run on mainline until the : next batch of enterprise distros drops, at which point the hardware where : this was done will be irrelevant for the benchmark. I'm sure any new : hardware will just set this distance to another yet arbitrary value to : make the kernel do what it wants. :) : : Also, when the hardware got _set_ to this initially, I complained. So, I : guess I'm getting my way now, with this patch. I'm cool with it. Reported-by: Robert Mueller Signed-off-by: KOSAKI Motohiro Acked-by: Christoph Lameter Acked-by: David Rientjes Reviewed-by: KAMEZAWA Hiroyuki Cc: Benjamin Herrenschmidt Cc: "Luck, Tony" Acked-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/topology.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/topology.h') diff --git a/include/linux/topology.h b/include/linux/topology.h index b91a40e847d2..fc839bfa7935 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -60,7 +60,7 @@ int arch_update_cpu_topology(void); * (in whatever arch specific measurement units returned by node_distance()) * then switch on zone reclaim on boot. */ -#define RECLAIM_DISTANCE 20 +#define RECLAIM_DISTANCE 30 #endif #ifndef PENALTY_FOR_NODE_WITH_CPUS #define PENALTY_FOR_NODE_WITH_CPUS (1) -- cgit v1.2.2