Re: [Qemu-devel] [PATCH v4] Fixes related to processing of qemu's -numa option

[Vinod, Chegu]

Thanks Eduardo !

Hi Anthony, If you are ok with this patch...could you pl pull these changes 
into upstream (or) 
suggest who I should talk to get these changes in ?

Thanks!
Vinod

-----Original Message-----
From: Eduardo Habkost [mailto:address@hidden 
Sent: Wednesday, July 18, 2012 10:15 AM
To: Vinod, Chegu
Cc: address@hidden; address@hidden; address@hidden
Subject: Re: [Qemu-devel] [PATCH v4] Fixes related to processing of qemu's 
-numa option

On Mon, Jul 16, 2012 at 09:31:30PM -0700, Chegu Vinod wrote:
> Changes since v3:
>    - using bitmap_set() instead of set_bit() in numa_add() routine.
>    - removed call to bitmak_zero() since bitmap_new() also zeros' the bitmap.
>    - Rebased to the latest qemu.

Tested-by: Eduardo Habkost <address@hidden>
Reviewed-by: Eduardo Habkost <address@hidden>


> 
> Changes since v2:
>    - Using "unsigned long *" for the node_cpumask[].
>    - Use bitmap_new() instead of g_malloc0() for allocation.
>    - Don't rely on "max_cpus" since it may not be initialized
>      before the numa related qemu options are parsed & processed.
> 
> Note: Continuing to use a new constant for allocation of
>       the mask (This constant is currently set to 255 since
>       with an 8bit APIC ID VCPUs can range from 0-254 in a
>       guest. The APIC ID 255 (0xFF) is reserved for broadcast).
> 
> Changes since v1:
> 
>    - Use bitmap functions that are already in qemu (instead
>      of cpu_set_t macro's from sched.h)
>    - Added a check for endvalue >= max_cpus.
>    - Fix to address the round-robbing assignment when
>      cpu's are not explicitly specified.
> -----------------------------------------------
> 
> v1:
> --
> 
> The -numa option to qemu is used to create [fake] numa nodes and 
> expose them to the guest OS instance.
> 
> There are a couple of issues with the -numa option:
> 
> a) Max VCPU's that can be specified for a guest while using
>    the qemu's -numa option is 64. Due to a typecasting issue
>    when the number of VCPUs is > 32 the VCPUs don't show up
>    under the specified [fake] numa nodes.
> 
> b) KVM currently has support for 160VCPUs per guest. The
>    qemu's -numa option has only support for upto 64VCPUs
>    per guest.
> This patch addresses these two issues.
> 
> Below are examples of (a) and (b)
> 
> a) >32 VCPUs are specified with the -numa option:
> 
> /usr/local/bin/qemu-system-x86_64 \
> -enable-kvm \
> 71:01:01 \
> -net tap,ifname=tap0,script=no,downscript=no \ -vnc :4
> 
> ...
> Upstream qemu :
> --------------
> 
> QEMU 1.1.50 monitor - type 'help' for more information
> (qemu) info numa
> 6 nodes
> node 0 cpus: 0 1 2 3 4 5 6 7 8 9 32 33 34 35 36 37 38 39 40 41 node 0 
> size: 131072 MB node 1 cpus: 10 11 12 13 14 15 16 17 18 19 42 43 44 45 
> 46 47 48 49 50 51 node 1 size: 131072 MB node 2 cpus: 20 21 22 23 24 
> 25 26 27 28 29 52 53 54 55 56 57 58 59 node 2 size: 131072 MB node 3 
> cpus: 30 node 3 size: 131072 MB node 4 cpus:
> node 4 size: 131072 MB
> node 5 cpus: 31
> node 5 size: 131072 MB
> 
> With the patch applied :
> -----------------------
> 
> QEMU 1.1.50 monitor - type 'help' for more information
> (qemu) info numa
> 6 nodes
> node 0 cpus: 0 1 2 3 4 5 6 7 8 9
> node 0 size: 131072 MB
> node 1 cpus: 10 11 12 13 14 15 16 17 18 19 node 1 size: 131072 MB node 
> 2 cpus: 20 21 22 23 24 25 26 27 28 29 node 2 size: 131072 MB node 3 
> cpus: 30 31 32 33 34 35 36 37 38 39 node 3 size: 131072 MB node 4 
> cpus: 40 41 42 43 44 45 46 47 48 49 node 4 size: 131072 MB node 5 
> cpus: 50 51 52 53 54 55 56 57 58 59 node 5 size: 131072 MB
> 
> b) >64 VCPUs specified with -numa option:
> 
> /usr/local/bin/qemu-system-x86_64 \
> -enable-kvm \
> -cpu 
> Westmere,+rdtscp,+pdpe1gb,+dca,+pdcm,+xtpr,+tm2,+est,+smx,+vmx,+ds_cpl
> ,+monitor,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+d-vnc :4
> 
> ...
> 
> Upstream qemu :
> --------------
> 
> only 63 CPUs in NUMA mode supported.
> only 64 CPUs in NUMA mode supported.
> QEMU 1.1.50 monitor - type 'help' for more information
> (qemu) info numa
> 8 nodes
> node 0 cpus: 6 7 8 9 38 39 40 41 70 71 72 73 node 0 size: 65536 MB 
> node 1 cpus: 10 11 12 13 14 15 16 17 18 19 42 43 44 45 46 47 48 49 50 
> 51 74 75 76 77 78 79 node 1 size: 65536 MB node 2 cpus: 20 21 22 23 24 
> 25 26 27 28 29 52 53 54 55 56 57 58 59 60 61 node 2 size: 65536 MB 
> node 3 cpus: 30 62 node 3 size: 65536 MB node 4 cpus:
> node 4 size: 65536 MB
> node 5 cpus:
> node 5 size: 65536 MB
> node 6 cpus: 31 63
> node 6 size: 65536 MB
> node 7 cpus: 0 1 2 3 4 5 32 33 34 35 36 37 64 65 66 67 68 69 node 7 
> size: 65536 MB
> 
> With the patch applied :
> -----------------------
> 
> QEMU 1.1.50 monitor - type 'help' for more information
> (qemu) info numa
> 8 nodes
> node 0 cpus: 0 1 2 3 4 5 6 7 8 9
> node 0 size: 65536 MB
> node 1 cpus: 10 11 12 13 14 15 16 17 18 19 node 1 size: 65536 MB node 
> 2 cpus: 20 21 22 23 24 25 26 27 28 29 node 2 size: 65536 MB node 3 
> cpus: 30 31 32 33 34 35 36 37 38 39 node 3 size: 65536 MB node 4 cpus: 
> 40 41 42 43 44 45 46 47 48 49 node 4 size: 65536 MB node 5 cpus: 50 51 
> 52 53 54 55 56 57 58 59 node 5 size: 65536 MB node 6 cpus: 60 61 62 63 
> 64 65 66 67 68 69 node 6 size: 65536 MB node 7 cpus: 70 71 72 73 74 75 
> 76 77 78 79
> 
> Signed-off-by: Chegu Vinod <address@hidden>, Jim Hull 
> <address@hidden>, Craig Hada <address@hidden>
> ---
>  cpus.c   |    3 ++-
>  hw/pc.c  |    3 ++-
>  sysemu.h |    3 ++-
>  vl.c     |   43 +++++++++++++++++++++----------------------
>  4 files changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/cpus.c b/cpus.c
> index b182b3d..acccd08 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -36,6 +36,7 @@
>  #include "cpus.h"
>  #include "qtest.h"
>  #include "main-loop.h"
> +#include "bitmap.h"
>  
>  #ifndef _WIN32
>  #include "compatfd.h"
> @@ -1145,7 +1146,7 @@ void set_numa_modes(void)
>  
>      for (env = first_cpu; env != NULL; env = env->next_cpu) {
>          for (i = 0; i < nb_numa_nodes; i++) {
> -            if (node_cpumask[i] & (1 << env->cpu_index)) {
> +            if (test_bit(env->cpu_index, node_cpumask[i])) {
>                  env->numa_node = i;
>              }
>          }
> diff --git a/hw/pc.c b/hw/pc.c
> index c7e9ab3..2edcc07 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -48,6 +48,7 @@
>  #include "memory.h"
>  #include "exec-memory.h"
>  #include "arch_init.h"
> +#include "bitmap.h"
>  
>  /* output Bochs bios info messages */  //#define DEBUG_BIOS @@ -639,7 
> +640,7 @@ static void *bochs_bios_init(void)
>      numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
>      for (i = 0; i < max_cpus; i++) {
>          for (j = 0; j < nb_numa_nodes; j++) {
> -            if (node_cpumask[j] & (1 << i)) {
> +            if (test_bit(i, node_cpumask[j])) {
>                  numa_fw_cfg[i + 1] = cpu_to_le64(j);
>                  break;
>              }
> diff --git a/sysemu.h b/sysemu.h
> index 6540c79..4669348 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -134,9 +134,10 @@ extern uint8_t qemu_extra_params_fw[2];  extern 
> QEMUClock *rtc_clock;
>  
>  #define MAX_NODES 64
> +#define MAX_CPUMASK_BITS 255
>  extern int nb_numa_nodes;
>  extern uint64_t node_mem[MAX_NODES];
> -extern uint64_t node_cpumask[MAX_NODES];
> +extern unsigned long *node_cpumask[MAX_NODES];
>  
>  #define MAX_OPTION_ROMS 16
>  typedef struct QEMUOptionRom {
> diff --git a/vl.c b/vl.c
> index 46248b9..35a641b 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -28,6 +28,7 @@
>  #include <errno.h>
>  #include <sys/time.h>
>  #include <zlib.h>
> +#include "bitmap.h"
>  
>  /* Needed early for CONFIG_BSD etc. */  #include "config-host.h"
> @@ -240,7 +241,7 @@ QTAILQ_HEAD(, FWBootEntry) fw_boot_order = 
> QTAILQ_HEAD_INITIALIZER(fw_boot_order
>  
>  int nb_numa_nodes;
>  uint64_t node_mem[MAX_NODES];
> -uint64_t node_cpumask[MAX_NODES];
> +unsigned long *node_cpumask[MAX_NODES];
>  
>  uint8_t qemu_uuid[16];
>  
> @@ -951,6 +952,8 @@ static void numa_add(const char *optarg)
>      unsigned long long value, endvalue;
>      int nodenr;
>  
> +    value = endvalue = 0ULL;
> +
>      optarg = get_opt_name(option, 128, optarg, ',') + 1;
>      if (!strcmp(option, "node")) {
>          if (get_param_value(option, 128, "nodeid", optarg) == 0) { @@ 
> -970,27 +973,22 @@ static void numa_add(const char *optarg)
>              }
>              node_mem[nodenr] = sval;
>          }
> -        if (get_param_value(option, 128, "cpus", optarg) == 0) {
> -            node_cpumask[nodenr] = 0;
> -        } else {
> +        if (get_param_value(option, 128, "cpus", optarg) != 0) {
>              value = strtoull(option, &endptr, 10);
> -            if (value >= 64) {
> -                value = 63;
> -                fprintf(stderr, "only 64 CPUs in NUMA mode supported.\n");
> +            if (*endptr == '-') {
> +                endvalue = strtoull(endptr+1, &endptr, 10);
>              } else {
> -                if (*endptr == '-') {
> -                    endvalue = strtoull(endptr+1, &endptr, 10);
> -                    if (endvalue >= 63) {
> -                        endvalue = 62;
> -                        fprintf(stderr,
> -                            "only 63 CPUs in NUMA mode supported.\n");
> -                    }
> -                    value = (2ULL << endvalue) - (1ULL << value);
> -                } else {
> -                    value = 1ULL << value;
> -                }
> +                endvalue = value;
> +            }
> +
> +            if (!(endvalue < MAX_CPUMASK_BITS)) {
> +                endvalue = MAX_CPUMASK_BITS - 1;
> +                fprintf(stderr,
> +                    "A max of %d CPUs are supported in a guest\n",
> +                     MAX_CPUMASK_BITS);
>              }
> -            node_cpumask[nodenr] = value;
> +
> +            bitmap_set(node_cpumask[nodenr], value, 
> + endvalue-value+1);
>          }
>          nb_numa_nodes++;
>      }
> @@ -2330,7 +2328,7 @@ int main(int argc, char **argv, char **envp)
>  
>      for (i = 0; i < MAX_NODES; i++) {
>          node_mem[i] = 0;
> -        node_cpumask[i] = 0;
> +        node_cpumask[i] = bitmap_new(MAX_CPUMASK_BITS);
>      }
>  
>      nb_numa_nodes = 0;
> @@ -3468,8 +3466,9 @@ int main(int argc, char **argv, char **envp)
>          }
>  
>          for (i = 0; i < nb_numa_nodes; i++) {
> -            if (node_cpumask[i] != 0)
> +            if (!bitmap_empty(node_cpumask[i], MAX_CPUMASK_BITS)) {
>                  break;
> +            }
>          }
>          /* assigning the VCPUs round-robin is easier to implement, guest OSes
>           * must cope with this anyway, because there are BIOSes out 
> there in @@ -3477,7 +3476,7 @@ int main(int argc, char **argv, char **envp)
>           */
>          if (i == nb_numa_nodes) {
>              for (i = 0; i < max_cpus; i++) {
> -                node_cpumask[i % nb_numa_nodes] |= 1 << i;
> +                set_bit(i, node_cpumask[i % nb_numa_nodes]);
>              }
>          }
>      }
> --
> 1.7.1
> 

-- 
Eduardo