Re: [Xen-devel] [PATCH 3 of 4] xl: add support for vif rate limiting

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 20 Mar 2012, Mathieu Gagnà wrote:
> The `rate` parameter specifies the rate at which the outgoing traffic
> will be limited to. This defaults to unlimited.
> 
> The `rate` keyword supports an optional time window parameter for specifying
> the granularity of credit replenishment. It determines the frequency at which
> the vif transmission credit is replenished. The default window is 50ms.
> 
> For example:
> 
>         'rate=10Mb/s'
>         'rate=250KB/s'
>         'rate=1MB/s@20ms'
> 
> Signed-off-by: Mathieu Gagnà <mgagne@xxxxxxxx>
> 
> diff --git a/docs/misc/xl-network-configuration.markdown 
> b/docs/misc/xl-network-configuration.markdown
> --- a/docs/misc/xl-network-configuration.markdown
> +++ b/docs/misc/xl-network-configuration.markdown
> @@ -122,5 +122,21 @@ Specifies the backend domain which this 
>  defaults to domain 0. Specifying another domain requires setting up a
>  driver domain which is outside the scope of this document.
>  
> +### rate
> +
> +Specifies the rate at which the outgoing traffic will be limited to. This
> +defaults to unlimited.
> +
> +The `rate` keyword supports an optional time window parameter for specifying
> +the granularity of credit replenishment. It determines the frequency at which
> +the vif transmission credit is replenished. The default window is 50ms.
> +
> +For example:
> +
> +        'rate=10Mb/s'
> +        'rate=250KB/s'
> +        'rate=1MB/s@20ms'
> +
> +
>  [oui]: http://en.wikipedia.org/wiki/Organizationally_Unique_Identifier
>  [net]: http://wiki.xen.org/wiki/HostConfiguration/Networking
> diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
> --- a/tools/libxl/Makefile
> +++ b/tools/libxl/Makefile
> @@ -57,7 +57,7 @@ LIBXL_OBJS += _libxl_types.o libxl_flask
>  AUTOINCS= libxlu_cfg_y.h libxlu_cfg_l.h _libxl_list.h
>  AUTOSRCS= libxlu_cfg_y.c libxlu_cfg_l.c
>  LIBXLU_OBJS = libxlu_cfg_y.o libxlu_cfg_l.o libxlu_cfg.o \
> -     libxlu_disk_l.o libxlu_disk.o
> +     libxlu_disk_l.o libxlu_disk.o libxlu_vif.o
>  $(LIBXLU_OBJS): CFLAGS += $(CFLAGS_libxenctrl) # For xentoollog.h
>  
>  CLIENTS = xl testidl
> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> --- a/tools/libxl/libxl.c
> +++ b/tools/libxl/libxl.c
> @@ -1834,6 +1834,13 @@ int libxl_device_nic_add(libxl_ctx *ctx,
>          flexarray_append(back, libxl__strdup(gc, nic->ip));
>      }
>  
> +    if (nic->rate_interval_usecs > 0) {
> +        flexarray_append(back, "rate");
> +        flexarray_append(back, libxl__sprintf(gc, "%u,%u",
> +                                              nic->rate_bytes_per_interval,
> +                                              nic->rate_interval_usecs));
> +    }
> +
>      flexarray_append(back, "bridge");
>      flexarray_append(back, libxl__strdup(gc, nic->bridge));
>      flexarray_append(back, "handle");
> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
> --- a/tools/libxl/libxl_types.idl
> +++ b/tools/libxl/libxl_types.idl
> @@ -341,6 +341,8 @@ libxl_device_nic = Struct("device_nic", 
>      ("ifname", string),
>      ("script", string),
>      ("nictype", libxl_nic_type),
> +    ("rate_bytes_per_interval", uint32),
> +    ("rate_interval_usecs", uint32),
>      ])
>  
>  libxl_device_pci = Struct("device_pci", [
> diff --git a/tools/libxl/libxlu_internal.h b/tools/libxl/libxlu_internal.h
> --- a/tools/libxl/libxlu_internal.h
> +++ b/tools/libxl/libxlu_internal.h
> @@ -17,9 +17,11 @@
>  #define LIBXLU_INTERNAL_H
>  
>  #include <stdio.h>
> +#include <stdlib.h>
>  #include <errno.h>
>  #include <string.h>
>  #include <assert.h>
> +#include <regex.h>
>  
>  #define XLU_ConfigList XLU_ConfigSetting
>  
> diff --git a/tools/libxl/libxlu_vif.c b/tools/libxl/libxlu_vif.c
> new file mode 100644
> --- /dev/null
> +++ b/tools/libxl/libxlu_vif.c
> @@ -0,0 +1,91 @@
> +#include "libxl_osdeps.h" /* must come before any other headers */
> +#include "libxlu_internal.h"
> +
> +static const char *vif_bytes_per_sec_re = "^([0-9]+)([GMK]?)([Bb])/s$";
> +static const char *vif_internal_usec_re = "^([0-9]+)([mu]?)s?$";
> +
> +static void vif_parse_rate_bytes_per_sec(const char *bytes, uint32_t 
> *bytes_per_sec)
> +{
> +    regex_t rec;
> +    uint64_t tmp_bytes_per_sec = 0;
> +
> +    regcomp(&rec, vif_bytes_per_sec_re, REG_EXTENDED);
> +    if (regexec(&rec, bytes, 0, NULL, 0) == 0) {
> +        const char *p = bytes;
> +        tmp_bytes_per_sec = strtoul(p, (char**)&p, 0);
> +        if (*p == 'G' || *p == '\0')
> +           tmp_bytes_per_sec *= 1000 * 1000 * 1000;
> +        else if (*p == 'M')
> +           tmp_bytes_per_sec *= 1000 * 1000;
> +        else if (*p == 'K')
> +           tmp_bytes_per_sec *= 1000;
> +        if (*p == 'b' || *(p+1) == 'b')
> +           tmp_bytes_per_sec /= 8;
> +    }
> +    regfree(&rec);
> +
> +    if (tmp_bytes_per_sec > UINT32_MAX || tmp_bytes_per_sec == 0)
> +        tmp_bytes_per_sec = UINT32_MAX;
> +    *bytes_per_sec = tmp_bytes_per_sec;
> +}
> +
> +static void vif_parse_rate_interval_usecs(const char *interval,
> +                                          uint32_t *interval_usecs)
> +{
> +    regex_t rec;
> +    uint64_t tmp_interval_usecs = 0;
> +
> +    regcomp(&rec, vif_internal_usec_re, REG_EXTENDED);
> +    if (regexec(&rec, interval, 0, NULL, 0) == 0) {
> +        const char *p = interval;
> +        tmp_interval_usecs = strtoul(p, (char**)&p, 10);
> +        if (*p == 's' || *p == '\0')
> +            tmp_interval_usecs *= 1000 * 1000;
> +        else if (*p == 'm')
> +            tmp_interval_usecs *= 1000;
> +    }
> +    regfree(&rec);
> +
> +    if (tmp_interval_usecs > UINT32_MAX || tmp_interval_usecs == 0)
> +        tmp_interval_usecs = UINT32_MAX;
> +    *interval_usecs = tmp_interval_usecs;
> +}
> +
> +void xlu_vif_parse_rate(const char *rate, uint32_t *bytes_per_interval,
> +                                          uint32_t *interval_usecs)
> +{
> +    uint32_t bytes_per_sec = 0;
> +    uint64_t tmp_bytes_per_interval = 0;
> +    char *tmprate, *ratetok;
> +
> +    tmprate = strdup(rate);
> +
> +    ratetok = strtok(tmprate, "@");
> +    vif_parse_rate_bytes_per_sec(ratetok, &bytes_per_sec);
> +
> +    ratetok = strtok(NULL, "@");
> +    if (ratetok != NULL)
> +        vif_parse_rate_interval_usecs(ratetok, interval_usecs);
> +    else
> +        *interval_usecs = 50000; /* Default to 50ms */
> +
> +    free(tmprate);
> +
> +    tmp_bytes_per_interval =
> +        (((uint64_t) bytes_per_sec * (uint64_t) *interval_usecs) / 1000000L);
> +
> +    /* overflow checking: default to unlimited rate */
> +    if ((tmp_bytes_per_interval == 0) || (tmp_bytes_per_interval > 
> UINT32_MAX)) {
> +        tmp_bytes_per_interval = UINT32_MAX;
> +        *interval_usecs = 0;
> +    }
> +    *bytes_per_interval = tmp_bytes_per_interval;
> +}

wouldn't it make sense to just use a uint64_t for
rate_bytes_per_interval and rate_interval_usecs?

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