Neel Natu wrote:

> Hi Roman,
> 
> On Sun, Apr 27, 2014 at 3:45 AM, Roman Bogorodskiy <no...@freebsd.org> wrote:
> > I've created an initial version of the patch which allows more flexible
> > vcpu pinning configuration.
> >
> > Current schema is:
> >
> > bhyve -p N
> >
> > pins vcpu i to hostcpu N + i.
> >
> > The propsed extension is:
> >
> > bhyve -p N:M .... -p 0:1 -p 3:5
> >
> > which pins vcpu N to host pcpu M. Option needs to be specified
> > individually for each vcpu.
> >
> > So it works like that for me:
> >
> > sudo /usr/sbin/bhyve -p 0:0 -p 1:3 -c 2 ...
> >
> > # sudo cpuset -g -t 100262
> > tid 100262 mask: 0
> > # sudo cpuset -g -t 100264
> > tid 100264 mask: 3
> >
> > PS I used cpumat_t* array to store these values instead of int, because
> > if the idea is OK, I'll extend it to support ranges like e.g. cpuset(1)
> > supports, e.g.: "1:2-5".
> >
> > The questions are:
> >
> >  - Is it OK to chance '-p' arg syntax or it's better to introduce a new
> >    one?
> >
> 
> I think we can reuse the "-p" option unless anybody objects vociferously.
> 
> >  - Is the syntax OK (currently: 'vcpu:pcpu', later
> >    'vcpu:pcpuN-pcpuM,pcpuX")?
> 
> Yup, I think that works fine.
> 
> The patch looks good in general but I have a few comments:
> 
> - Scope of 'vcpupmap[]' should be restricted to 'static'.
> 
> - usage() and man page need to be updated.
> 
> - pincpu_parse():
> The option parsing can be made much easier by using:
> 
>   if (sscanf(str, "%d:%d", &vcpu, &pcpu) == 2) {
>           /* success */
>   } else {
>           return (-1);
>   }
> 
> If the same vcpu is specified multiple times then we should
> malloc(sizeof(cpuset_t)) only the first time:
> 
>   if (vcpumap[vcpu] != NULL)
>           mask = vcpumap[vcpu];
>   else
>           mask = malloc(sizeof(cpuset_t));
> 
> We need to range-check 'vcpu' before using it as an index into the
> 'vcpumap[]' array.
> 
> best
> Neel

Attached an updated patch.

I'm still inclined to use something like parselist() from
usr.bin/cpuset/cpuset.c, but I don't want to copy/paste and I don't know
where it'd make sense to move it so it was usable outside of cpuset?

PS While reading bhyverun.c, I think I spotted a typo: in fbsdrun_deletecpu()
error message says fprintf(stderr, "addcpu: .... Should it be "deletecpu:" 
instead?

Roman Bogorodskiy
Index: bhyve.8
===================================================================
--- bhyve.8	(revision 264921)
+++ bhyve.8	(working copy)
@@ -78,12 +78,14 @@
 allow a remote kernel kgdb to be relayed to the guest kernel gdb stub
 via a local IPv4 address and this port.
 This option will be deprecated in a future version.
-.It Fl p Ar pinnedcpu
+.It Fl p Ar n:m
 Force guest virtual CPUs to be pinned to host CPUs.
 Virtual CPU
 .Em n
 is pinned to host CPU
-.Em pinnedcpu+n .
+.Em m .
+This option could be specified multiple times to set pinning for each
+Virtual CPU and to pin Virtual CPU to more than one host CPU.
 .It Fl P
 Force the guest virtual CPU to exit when a PAUSE instruction is detected.
 .It Fl W
Index: bhyverun.c
===================================================================
--- bhyverun.c	(revision 264921)
+++ bhyverun.c	(working copy)
@@ -83,7 +83,6 @@
 
 int guest_ncpus;
 
-static int pincpu = -1;
 static int guest_vmexit_on_hlt, guest_vmexit_on_pause, disable_x2apic;
 static int virtio_msix = 1;
 
@@ -119,6 +118,8 @@
 	int		mt_vcpu;	
 } mt_vmm_info[VM_MAXCPU];
 
+static cpuset_t *vcpumap[VM_MAXCPU] = { NULL };
+
 static void
 usage(int code)
 {
@@ -125,12 +126,12 @@
 
         fprintf(stderr,
                 "Usage: %s [-aehwAHIPW] [-g <gdb port>] [-s <pci>] [-S <pci>]\n"
-		"       %*s [-c vcpus] [-p pincpu] [-m mem] [-l <lpc>] <vm>\n"
+		"       %*s [-c vcpus] [-p vcpu:hostcpu] [-m mem] [-l <lpc>] <vm>\n"
 		"       -a: local apic is in XAPIC mode (default is X2APIC)\n"
 		"       -A: create an ACPI table\n"
 		"       -g: gdb port\n"
 		"       -c: # cpus (default 1)\n"
-		"       -p: pin vcpu 'n' to host cpu 'pincpu + n'\n"
+		"       -p: <n:m> pin vcpu 'n' to host cpu 'm'\n"
 		"       -H: vmexit from the guest on hlt\n"
 		"       -P: vmexit from the guest on pause\n"
 		"       -W: force virtio to use single-vector MSI\n"
@@ -146,6 +147,53 @@
 	exit(code);
 }
 
+static int
+pincpu_parse(const char *cpupin)
+{
+    char *string;
+    int vcpu = -1, pcpu = -1, ret = -1;
+
+    if ((string = strdup(cpupin)) == NULL) {
+        fprintf(stderr, "strdup failed: %d\n", errno);
+        return -1;
+    }
+
+    if (sscanf(string, "%d:%d", &vcpu, &pcpu) != 2) {
+        fprintf(stderr, "invalid format: %s\n", string);
+        goto cleanup;
+    }
+
+    if (vcpu < 0 || vcpu > VM_MAXCPU - 1) {
+        fprintf(stderr, "invalid vcpu value '%d', "
+                "should be from 0 to %d\n",
+                vcpu, VM_MAXCPU - 1);
+        goto cleanup;
+    }
+
+    if (pcpu < 0 || pcpu > CPU_SETSIZE) {
+        fprintf(stderr, "invalid pcpu value '%d', "
+                "should be from 0 to %d\n",
+                pcpu, CPU_SETSIZE);
+        goto cleanup;
+    }
+
+    if (vcpumap[vcpu] == NULL) {
+        if ((vcpumap[vcpu] = malloc(sizeof(cpuset_t))) == NULL) {
+            fprintf(stderr, "malloc failed: %d\n", errno);
+            goto cleanup;
+        }
+        CPU_ZERO(vcpumap[vcpu]);
+    }
+    CPU_SET(pcpu, vcpumap[vcpu]);
+
+    ret = 0;
+
+cleanup:
+    free(string);
+
+    return ret;
+}
+
 void *
 paddr_guest2host(struct vmctx *ctx, uintptr_t gaddr, size_t len)
 {
@@ -479,15 +527,13 @@
 static void
 vm_loop(struct vmctx *ctx, int vcpu, uint64_t rip)
 {
-	cpuset_t mask;
 	int error, rc, prevcpu;
 	enum vm_exitcode exitcode;
 
-	if (pincpu >= 0) {
-		CPU_ZERO(&mask);
-		CPU_SET(pincpu + vcpu, &mask);
+	if (vcpumap[vcpu] != NULL) {
 		error = pthread_setaffinity_np(pthread_self(),
-					       sizeof(mask), &mask);
+					       sizeof(cpuset_t),
+                                               vcpumap[vcpu]);
 		assert(error == 0);
 	}
 
@@ -622,7 +668,10 @@
 			bvmcons = 1;
 			break;
 		case 'p':
-			pincpu = atoi(optarg);
+                        if (pincpu_parse(optarg) < 0) {
+                            errx(EX_USAGE, "invalid cpu pin "
+                                 "configuration '%s'", optarg);
+                        }
 			break;
                 case 'c':
 			guest_ncpus = atoi(optarg);

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