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Re: [Qemu-arm] [Qemu-devel] [PATCH v3] Allow setting NUMA distance for d
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From: |
Igor Mammedov |
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Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH v3] Allow setting NUMA distance for different NUMA nodes |
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Date: |
Wed, 29 Mar 2017 13:44:58 +0200 |
On Wed, 29 Mar 2017 16:50:00 +0800
He Chen <address@hidden> wrote:
> On Thu, Mar 23, 2017 at 10:29:55AM +0100, Igor Mammedov wrote:
> > On Wed, 22 Mar 2017 17:32:46 +0800
> > He Chen <address@hidden> wrote:
> >
> > > Current, QEMU does not provide a clear command to set vNUMA distance for
> > > guest although we already have `-numa` command to set vNUMA nodes.
> > >
> > > vNUMA distance makes sense in certain scenario.
> > > But now, if we create a guest that has 4 vNUMA nodes, when we check NUMA
> > > info via `numactl -H`, we will see:
> > >
> > > node distance:
> > > node 0 1 2 3
> > > 0: 10 20 20 20
> > > 1: 20 10 20 20
> > > 2: 20 20 10 20
> > > 3: 20 20 20 10
> > >
> > > Guest kernel regards all local node as distance 10, and all remote node
> > > as distance 20 when there is no SLIT table since QEMU doesn't build it.
> > > It looks like a little strange when you have seen the distance in an
> > > actual physical machine that contains 4 NUMA nodes. My machine shows:
> > >
> > > node distance:
> > > node 0 1 2 3
> > > 0: 10 21 31 41
> > > 1: 21 10 21 31
> > > 2: 31 21 10 21
> > > 3: 41 31 21 10
> > >
> > > To set vNUMA distance, guest should see a complete SLIT table.
> > > I found QEMU has provide `-acpitable` command that allows users to add
> > > a ACPI table into guest, but it requires users building ACPI table by
> > > themselves first. Using `-acpitable` to add a SLIT table may be not so
> > > straightforward or flexible, imagine that when the vNUMA configuration
> > > is changes and we need to generate another SLIT table manually. It may
> > > not be friendly to users or upper software like libvirt.
> > >
> > > This patch is going to add SLIT table support in QEMU, and provides
> > > additional option `dist` for command `-numa` to allow user set vNUMA
> > > distance by QEMU command.
> > >
> > > With this patch, when a user wants to create a guest that contains
> > > several vNUMA nodes and also wants to set distance among those nodes,
> > > the QEMU command would like:
> > >
> > > ```
> > > -object
> > > memory-backend-ram,size=1G,prealloc=yes,host-nodes=0,policy=bind,id=node0
> > > \
> > > -numa node,nodeid=0,cpus=0,memdev=node0 \
> > > -object
> > > memory-backend-ram,size=1G,prealloc=yes,host-nodes=1,policy=bind,id=node1
> > > \
> > > -numa node,nodeid=1,cpus=1,memdev=node1 \
> > > -object
> > > memory-backend-ram,size=1G,prealloc=yes,host-nodes=2,policy=bind,id=node2
> > > \
> > > -numa node,nodeid=2,cpus=2,memdev=node2 \
> > > -object
> > > memory-backend-ram,size=1G,prealloc=yes,host-nodes=3,policy=bind,id=node3
> > > \
> > > -numa node,nodeid=3,cpus=3,memdev=node3 \
> > > -numa dist,src=0,dst=1,val=21 \
> > > -numa dist,src=0,dst=2,val=31 \
> > > -numa dist,src=0,dst=3,val=41 \
> > > -numa dist,src=1,dst=0,val=21 \
> > > ...
> > > ```
> > >
> > > Signed-off-by: He Chen <address@hidden>
> > >
> > > fix
> > > ---
> > > hw/acpi/aml-build.c | 26 +++++++++++++++++++++++++
> > > hw/arm/virt-acpi-build.c | 2 ++
> > > hw/i386/acpi-build.c | 2 ++
> > > include/hw/acpi/aml-build.h | 1 +
> > > include/sysemu/numa.h | 1 +
> > > include/sysemu/sysemu.h | 4 ++++
> > > numa.c | 47
> > > +++++++++++++++++++++++++++++++++++++++++++++
> > > qapi-schema.json | 30 ++++++++++++++++++++++++++---
> > > qemu-options.hx | 12 +++++++++++-
> > > 9 files changed, 121 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> > > index c6f2032..410b30e 100644
> > > --- a/hw/acpi/aml-build.c
> > > +++ b/hw/acpi/aml-build.c
> > > @@ -24,6 +24,7 @@
> > > #include "hw/acpi/aml-build.h"
> > > #include "qemu/bswap.h"
> > > #include "qemu/bitops.h"
> > > +#include "sysemu/numa.h"
> > >
> > > static GArray *build_alloc_array(void)
> > > {
> > > @@ -1609,3 +1610,28 @@ void build_srat_memory(AcpiSratMemoryAffinity
> > > *numamem, uint64_t base,
> > > numamem->base_addr = cpu_to_le64(base);
> > > numamem->range_length = cpu_to_le64(len);
> > > }
> > > +
> > > +/*
> > > + * ACPI spec 5.2.17 System Locality Distance Information Table
> > > + * (Revision 2.0 or later)
> > > + */
> > > +void build_slit(GArray *table_data, BIOSLinker *linker)
> > > +{
> > > + int slit_start, i, j;
> > > + slit_start = table_data->len;
> > > +
> > > + acpi_data_push(table_data, sizeof(AcpiTableHeader));
> > > +
> > > + build_append_int_noprefix(table_data, nb_numa_nodes, 8);
> > > + for (i = 0; i < nb_numa_nodes; i++) {
> > > + for (j = 0; j < nb_numa_nodes; j++) {
> > > + build_append_int_noprefix(table_data,
> > > numa_info[i].distance[j], 1);
> > > + }
> > > + }
> > > +
> > > + build_header(linker, table_data,
> > > + (void *)(table_data->data + slit_start),
> > > + "SLIT",
> > > + table_data->len - slit_start, 1, NULL, NULL);
> > > +}
> > > +
> > > diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> > > index 0835e59..d9e6828 100644
> > > --- a/hw/arm/virt-acpi-build.c
> > > +++ b/hw/arm/virt-acpi-build.c
> > > @@ -781,6 +781,8 @@ void virt_acpi_build(VirtMachineState *vms,
> > > AcpiBuildTables *tables)
> > > if (nb_numa_nodes > 0) {
> > > acpi_add_table(table_offsets, tables_blob);
> > > build_srat(tables_blob, tables->linker, vms);
> > > + acpi_add_table(table_offsets, tables_blob);
> > > + build_slit(tables_blob, tables->linker);
> > > }
> > >
> > > if (its_class_name() && !vmc->no_its) {
> > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > index 2073108..12730ea 100644
> > > --- a/hw/i386/acpi-build.c
> > > +++ b/hw/i386/acpi-build.c
> > > @@ -2678,6 +2678,8 @@ void acpi_build(AcpiBuildTables *tables,
> > > MachineState *machine)
> > > if (pcms->numa_nodes) {
> > > acpi_add_table(table_offsets, tables_blob);
> > > build_srat(tables_blob, tables->linker, machine);
> > > + acpi_add_table(table_offsets, tables_blob);
> > > + build_slit(tables_blob, tables->linker);
> > > }
> > > if (acpi_get_mcfg(&mcfg)) {
> > > acpi_add_table(table_offsets, tables_blob);
> > > diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
> > > index 00c21f1..329a0d0 100644
> > > --- a/include/hw/acpi/aml-build.h
> > > +++ b/include/hw/acpi/aml-build.h
> > > @@ -389,4 +389,5 @@ GCC_FMT_ATTR(2, 3);
> > > void build_srat_memory(AcpiSratMemoryAffinity *numamem, uint64_t base,
> > > uint64_t len, int node, MemoryAffinityFlags
> > > flags);
> > >
> > > +void build_slit(GArray *table_data, BIOSLinker *linker);
> > > #endif
> > > diff --git a/include/sysemu/numa.h b/include/sysemu/numa.h
> > > index 8f09dcf..2f7a941 100644
> > > --- a/include/sysemu/numa.h
> > > +++ b/include/sysemu/numa.h
> > > @@ -21,6 +21,7 @@ typedef struct node_info {
> > > struct HostMemoryBackend *node_memdev;
> > > bool present;
> > > QLIST_HEAD(, numa_addr_range) addr; /* List to store address ranges
> > > */
> > > + uint8_t distance[MAX_NODES];
> > > } NodeInfo;
> > >
> > > extern NodeInfo numa_info[MAX_NODES];
> > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> > > index 576c7ce..a4e328d 100644
> > > --- a/include/sysemu/sysemu.h
> > > +++ b/include/sysemu/sysemu.h
> > > @@ -169,6 +169,10 @@ extern int mem_prealloc;
> > >
> > > #define MAX_NODES 128
> > > #define NUMA_NODE_UNASSIGNED MAX_NODES
> > > +#define MIN_NUMA_DISTANCE 10
> > > +#define DEF_NUMA_DISTANCE 20
> > > +#define MAX_NUMA_DISTANCE 254
> > > +#define NUMA_DISTANCE_UNREACHABLE 255
> > >
> > > #define MAX_OPTION_ROMS 16
> > > typedef struct QEMUOptionRom {
> > > diff --git a/numa.c b/numa.c
> > > index e01cb54..425a320 100644
> > > --- a/numa.c
> > > +++ b/numa.c
> > > @@ -212,6 +212,28 @@ static void numa_node_parse(NumaNodeOptions *node,
> > > QemuOpts *opts, Error **errp)
> > > max_numa_nodeid = MAX(max_numa_nodeid, nodenr + 1);
> > > }
> > >
> > > +static void numa_distance_parse(NumaDistOptions *dist, QemuOpts *opts,
> > > Error **errp)
> > > +{
> > > + uint64_t src = dist->src;
> > > + uint64_t dst = dist->dst;
> > > + uint8_t val = dist->val;
> > > +
> > > + if (src >= MAX_NODES || dst >= MAX_NODES) {
> > this allows to specify any src/dst instead of present nodes only,
> > you should probably check that src/dst are present here,
> > see: numa_info[x].present
> >
> > if node is not present complain that it should be declared with
> > '-numa node' option first and exit.
> >
> Thanks for pointing out this.
>
> > > + error_setg(errp, "Max number of NUMA nodes reached: %"
> > > + PRIu64 "", src > dst ? src : dst);
> > > + return;
> > > + }
> > > +
> > > + if (val < MIN_NUMA_DISTANCE || val > MAX_NUMA_DISTANCE) {
> > > + error_setg(errp,
> > > + "NUMA distance (%" PRIu8 ") out of range (%d) ~ (%d)",
> > > + dist->val, MIN_NUMA_DISTANCE, MAX_NUMA_DISTANCE);
> > > + return;
> > > + }
> > > +
> > > + numa_info[src].distance[dst] = val;
> > > +}
> > > +
> > > static int parse_numa(void *opaque, QemuOpts *opts, Error **errp)
> > > {
> > > NumaOptions *object = NULL;
> > > @@ -235,6 +257,12 @@ static int parse_numa(void *opaque, QemuOpts *opts,
> > > Error **errp)
> > > }
> > > nb_numa_nodes++;
> > > break;
> > > + case NUMA_OPTIONS_TYPE_DIST:
> > > + numa_distance_parse(&object->u.dist, opts, &err);
> > > + if (err) {
> > > + goto end;
> > > + }
> > > + break;
> > > default:
> > > abort();
> > > }
> > > @@ -294,6 +322,24 @@ static void validate_numa_cpus(void)
> > > g_free(seen_cpus);
> > > }
> > >
> > > +static void default_numa_distance(void)
> > > +{
> > > + int src, dst;
> > > +
> > fill in defaults only if there weren't any '-numa dist' on CLI
> > and refuse to start if partial filled table were explicitly provided on CLI
> >
> I am afraid that I may have a bad function name here, fill_numa_distance
> might be a better name?
>
> Also, since the distance can be asymmetric, IMHO, providing a partial
> filled table looks fine. If we set many NUMA nodes e.g. 8 nodes for
> guest, the whole filled table would require many command lines which
> might be inconvenient and less flexible.
asymmetric doesn't imply sparse, so one has to specify full matrix
it might be inconvenient /long/ but is very flexible.
if you want shorten CLI maybe adding an extra option could help:
-numa dist,default=xxx
that way QEMU won't have to maintain default value and it would
be up to user maintain it.
> Please correct me if I am wrong, thanks.
> > > + for (src = 0; src < nb_numa_nodes; src++) {
> > > + for (dst = 0; dst < nb_numa_nodes; dst++) {
> > > + if (src == dst && numa_info[src].distance[dst] !=
> > > MIN_NUMA_DISTANCE) {
> > > + numa_info[src].distance[dst] = MIN_NUMA_DISTANCE;
spec says that diagonal element of matrix are equal to 10,
there shouldn't by silent fixup.
If user provided wrong value just error out pointing to CLI mistake.
May be add diagonal check to numa_distance_parse()
> > > + } else if (numa_info[src].distance[dst] <=
> > > MIN_NUMA_DISTANCE) {
> > > + if (numa_info[dst].distance[src] > MIN_NUMA_DISTANCE)
> > > + numa_info[src].distance[dst] =
> > > numa_info[dst].distance[src];
> > > + else
> > > + numa_info[src].distance[dst] = DEF_NUMA_DISTANCE;
> > > + }
> > > + }
> > > + }
> > > +}
> > > +
> > > void parse_numa_opts(MachineClass *mc)
> > > {
> > > int i;
> > > @@ -390,6 +436,7 @@ void parse_numa_opts(MachineClass *mc)
> > > }
> > >
> > > validate_numa_cpus();
> > > + default_numa_distance();
> > > } else {
> > > numa_set_mem_node_id(0, ram_size, 0);
> > > }
> > > diff --git a/qapi-schema.json b/qapi-schema.json
> > > index 32b4a4b..21ad94a 100644
> > > --- a/qapi-schema.json
> > > +++ b/qapi-schema.json
> > > @@ -5644,15 +5644,19 @@
> > > ##
> > > # @NumaOptionsType:
> > > #
> > > +# @node: NUMA nodes configuration
> > > +#
> > > +# @dist: NUMA distance configuration
> > > +#
> > > # Since: 2.1
> > > ##
> > > { 'enum': 'NumaOptionsType',
> > > - 'data': [ 'node' ] }
> > > + 'data': [ 'node', 'dist' ] }
> > >
> > > ##
> > > # @NumaOptions:
> > > #
> > > -# A discriminated record of NUMA options. (for OptsVisitor)
> > > +# A discriminated record of NUMA options.
> > unrelated change?
> >
> > > #
> > > # Since: 2.1
> > > ##
> > > @@ -5660,7 +5664,8 @@
> > > 'base': { 'type': 'NumaOptionsType' },
> > > 'discriminator': 'type',
> > > 'data': {
> > > - 'node': 'NumaNodeOptions' }}
> > > + 'node': 'NumaNodeOptions',
> > > + 'dist': 'NumaDistOptions' }}
> > >
> > > ##
> > > # @NumaNodeOptions:
> > > @@ -5689,6 +5694,25 @@
> > > '*memdev': 'str' }}
> > >
> > > ##
> > > +# @NumaDistOptions:
> > > +#
> > > +# Set distance between 2 NUMA nodes. (for OptsVisitor)
> > > +#
> > > +# @src: source NUMA node.
> > > +#
> > > +# @dst: destination NUMA node.
> > > +#
> > > +# @val: NUMA distance from source node to destination node.
> > > +#
> > > +# Since: 2.10
> > > +##
> > > +{ 'struct': 'NumaDistOptions',
> > > + 'data': {
> > > + 'src': 'uint64',
> > > + 'dst': 'uint64',
> > nodeid is uint16, so probably these should be also uint16
> >
> >
> > > + 'val': 'uint8' }}
> > > +
> > > +##
> > > # @HostMemPolicy:
> > > #
> > > # Host memory policy types
> > > diff --git a/qemu-options.hx b/qemu-options.hx
> > > index 8dd8ee3..43c3950 100644
> > > --- a/qemu-options.hx
> > > +++ b/qemu-options.hx
> > > @@ -139,12 +139,15 @@ ETEXI
> > >
> > > DEF("numa", HAS_ARG, QEMU_OPTION_numa,
> > > "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
> > > - "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n",
> > > QEMU_ARCH_ALL)
> > > + "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
> > > + "-numa dist,src=source,dst=destination,val=distance\n",
> > > QEMU_ARCH_ALL)
> > > STEXI
> > > @item -numa
> > > node[,address@hidden,address@hidden@var{lastcpu}]][,address@hidden
> > > @itemx -numa
> > > node[,address@hidden,address@hidden@var{lastcpu}]][,address@hidden
> > > address@hidden -numa dist,address@hidden,address@hidden,address@hidden
> > > @findex -numa
> > > Define a NUMA node and assign RAM and VCPUs to it.
> > > +Set NUMA distance from source node to destination node.
> > >
> > > @var{firstcpu} and @var{lastcpu} are CPU indexes. Each
> > > @samp{cpus} option represent a contiguous range of CPU indexes
> > > @@ -167,6 +170,13 @@ split equally between them.
> > > @samp{mem} and @samp{memdev} are mutually exclusive. Furthermore,
> > > if one node uses @samp{memdev}, all of them have to use it.
> > >
> > > address@hidden and @var{destination} are NUMA node IDs.
> > > address@hidden is the NUMA distance from @var{source} to
> > > @var{destination}.
> > > +The distance from node A to node B may be different from the distance
> > > from
> > > +node B to node A since the distance can to be asymmetry.
> > > +If the distance is not set, the default distance for a local NUMA node
> > > is 10,
> > > +and 20 for a remote node.
> > > +
> > > Note that the address@hidden option doesn't allocate any of the
> > > specified resources, it just assigns existing resources to NUMA
> > > nodes. This means that one still has to use the @option{-m},
> >