Messages in this thread Patch in this message | | | From | Petr Holasek <> | Subject | [PATCH 1/2] NUMA emulation x86_64: numa=fake parameter for custom nodes distance | Date | Fri, 18 Nov 2011 12:55:07 +0100 |
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As default, when numa emulation is turned on, node distance table uses physical distance, so for 4 nodes emulated on 1 physical table is
node 0 1 2 3 0: 10 10 10 10 1: 10 10 10 10 2: 10 10 10 10 3: 10 10 10 10
This patch adds new [distance] argument to
numa=fake=<number/size of nodes>[,distance]
When distance argument is used, it sets linear distance between nodes like that:
__distance__ ___|___ ____|___ ________ ________ | | | | | | | | | node1 |---| node 2 |---| node 3 |---| node 4 | |_______| |________| |________| |________| | | | | | | |____distance * 2________| | | | |____________distance * 3______________|
This feature might be useful for testing some numa awareness features in both user and kernel spaces.
Signed-off-by: Petr Holasek <pholasek@redhat.com> --- arch/x86/mm/numa_emulation.c | 16 ++++++++++++++++ 1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c index d0ed086..1824972 100644 --- a/arch/x86/mm/numa_emulation.c +++ b/arch/x86/mm/numa_emulation.c @@ -309,6 +309,8 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) u8 *phys_dist = NULL; size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]); int max_emu_nid, dfl_phys_nid; + unsigned long dist_level; + char *c; int i, j, ret; if (!emu_cmdline) @@ -404,6 +406,17 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) if (emu_nid_to_phys[i] == NUMA_NO_NODE) emu_nid_to_phys[i] = dfl_phys_nid; + /* load distance level parameter */ + dist_level = -1; + c = strchr(emu_cmdline, ','); + if (c) { + c++; + ret = kstrtoul(c, 10, &dist_level); + if (ret < 0 || dist_level < LOCAL_DISTANCE || + dist_level * max_emu_nid > ULONG_MAX) + dist_level = -1; + } + /* transform distance table */ numa_reset_distance(); for (i = 0; i < max_emu_nid + 1; i++) { @@ -418,6 +431,9 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) else dist = phys_dist[physi * numa_dist_cnt + physj]; + if (dist_level != -1 && i != j) + dist = abs(i - j) * dist_level; + numa_set_distance(i, j, dist); } } -- 1.7.6.4
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