Re: [Qemu-devel] [PATCH v10 1/3] block: add the command line support

[Ryan Harper]

* Zhi Yong Wu <address@hidden> [2011-11-01 02:44]:
> Signed-off-by: Zhi Yong Wu <address@hidden>
> ---
>  block.c         |   40 ++++++++++++++++++++++++++++++++++++++++
>  block.h         |    4 ++++
>  block_int.h     |   29 +++++++++++++++++++++++++++++
>  blockdev.c      |   32 ++++++++++++++++++++++++++++++++
>  qemu-config.c   |   24 ++++++++++++++++++++++++
>  qemu-options.hx |    1 +
>  6 files changed, 130 insertions(+), 0 deletions(-)

I suggest changing the Subject of the patch to include something about
blkio limits.  This will in searching git log later that this patch was
introducing blkio command line support.

> 
> diff --git a/block.c b/block.c
> index 9bb236c..8f08dc5 100644
> --- a/block.c
> +++ b/block.c
> @@ -30,6 +30,7 @@
>  #include "qjson.h"
>  #include "qemu-coroutine.h"
>  #include "qmp-commands.h"
> +#include "qemu-timer.h"
> 
>  #ifdef CONFIG_BSD
>  #include <sys/types.h>
> @@ -105,6 +106,37 @@ int is_windows_drive(const char *filename)
>  }
>  #endif
> 
> +/* throttling disk I/O limits */
> +static void bdrv_block_timer(void *opaque)
> +{
> +    BlockDriverState *bs = opaque;
> +
> +    qemu_co_queue_next(&bs->throttled_reqs);
> +}
> +
> +void bdrv_io_limits_enable(BlockDriverState *bs)
> +{
> +    bs->io_limits_enabled = true;

We may want to move this to the end of the function so we don't raise
the flag that we're enabled until we're done setting everything up.
I don't think we'll race right now, but no reason not to move this to
the end.

> +    qemu_co_queue_init(&bs->throttled_reqs);
> +
> +    bs->block_timer   = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs);
> +    bs->slice_time    = 5 * BLOCK_IO_SLICE_TIME;
> +    bs->slice_start   = qemu_get_clock_ns(vm_clock);
> +    bs->slice_end     = bs->slice_start + bs->slice_time;
> +    memset(&bs->io_disps, 0, sizeof(bs->io_disps));
> +}
> +
> +bool bdrv_io_limits_enabled(BlockDriverState *bs)
> +{
> +    BlockIOLimit *io_limits = &bs->io_limits;
> +    return io_limits->bps[BLOCK_IO_LIMIT_READ]
> +         || io_limits->bps[BLOCK_IO_LIMIT_WRITE]
> +         || io_limits->bps[BLOCK_IO_LIMIT_TOTAL]
> +         || io_limits->iops[BLOCK_IO_LIMIT_READ]
> +         || io_limits->iops[BLOCK_IO_LIMIT_WRITE]
> +         || io_limits->iops[BLOCK_IO_LIMIT_TOTAL];
> +}
> +
>  /* check if the path starts with "<protocol>:" */
>  static int path_has_protocol(const char *path)
>  {
> @@ -1519,6 +1551,14 @@ void bdrv_get_geometry_hint(BlockDriverState *bs,
>      *psecs = bs->secs;
>  }
> 
> +/* throttling disk io limits */
> +void bdrv_set_io_limits(BlockDriverState *bs,
> +                            BlockIOLimit *io_limits)
> +{
> +    bs->io_limits = *io_limits;
> +    bs->io_limits_enabled = bdrv_io_limits_enabled(bs);
> +}
> +
>  /* Recognize floppy formats */
>  typedef struct FDFormat {
>      FDriveType drive;
> diff --git a/block.h b/block.h
> index 38cd748..bc8315d 100644
> --- a/block.h
> +++ b/block.h
> @@ -89,6 +89,10 @@ void bdrv_info(Monitor *mon, QObject **ret_data);
>  void bdrv_stats_print(Monitor *mon, const QObject *data);
>  void bdrv_info_stats(Monitor *mon, QObject **ret_data);
> 
> +/* disk I/O throttling */
> +void bdrv_io_limits_enable(BlockDriverState *bs);
> +bool bdrv_io_limits_enabled(BlockDriverState *bs);
> +
>  void bdrv_init(void);
>  void bdrv_init_with_whitelist(void);
>  BlockDriver *bdrv_find_protocol(const char *filename);
> diff --git a/block_int.h b/block_int.h
> index f4547f6..b835ef6 100644
> --- a/block_int.h
> +++ b/block_int.h
> @@ -34,6 +34,12 @@
>  #define BLOCK_FLAG_ENCRYPT   1
>  #define BLOCK_FLAG_COMPAT6   4
> 
> +#define BLOCK_IO_LIMIT_READ     0
> +#define BLOCK_IO_LIMIT_WRITE    1
> +#define BLOCK_IO_LIMIT_TOTAL    2
> +
> +#define BLOCK_IO_SLICE_TIME     100000000
> +
>  #define BLOCK_OPT_SIZE          "size"
>  #define BLOCK_OPT_ENCRYPT       "encryption"
>  #define BLOCK_OPT_COMPAT6       "compat6"
> @@ -50,6 +56,16 @@ typedef struct AIOPool {
>      BlockDriverAIOCB *free_aiocb;
>  } AIOPool;
> 
> +typedef struct BlockIOLimit {
> +    uint64_t bps[3];
> +    uint64_t iops[3];
> +} BlockIOLimit;
> +
> +typedef struct BlockIODisp {
> +    uint64_t bytes[2];
> +    uint64_t ios[2];
> +} BlockIODisp;
> +
>  struct BlockDriver {
>      const char *format_name;
>      int instance_size;
> @@ -184,6 +200,16 @@ struct BlockDriverState {
> 
>      void *sync_aiocb;
> 
> +    /* the time for latest disk I/O */
> +    int64_t slice_time;
> +    int64_t slice_start;
> +    int64_t slice_end;
> +    BlockIOLimit io_limits;
> +    BlockIODisp  io_disps;
> +    CoQueue      throttled_reqs;
> +    QEMUTimer    *block_timer;
> +    bool         io_limits_enabled;
> +
>      /* I/O stats (display with "info blockstats"). */
>      uint64_t nr_bytes[BDRV_MAX_IOTYPE];
>      uint64_t nr_ops[BDRV_MAX_IOTYPE];
> @@ -227,6 +253,9 @@ void *qemu_aio_get(AIOPool *pool, BlockDriverState *bs,
>                     BlockDriverCompletionFunc *cb, void *opaque);
>  void qemu_aio_release(void *p);
> 
> +void bdrv_set_io_limits(BlockDriverState *bs,
> +                        BlockIOLimit *io_limits);
> +
>  #ifdef _WIN32
>  int is_windows_drive(const char *filename);
>  #endif
> diff --git a/blockdev.c b/blockdev.c
> index 0827bf7..faf8c56 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -235,6 +235,9 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
>      int on_read_error, on_write_error;
>      const char *devaddr;
>      DriveInfo *dinfo;
> +    BlockIOLimit io_limits;
> +    bool bps_iol;
> +    bool iops_iol;
>      int snapshot = 0;
>      int ret;
> 
> @@ -353,6 +356,32 @@ DriveInfo *drive_init(QemuOpts *opts, int 
> default_to_scsi)
>          }
>      }
> 
> +    /* disk I/O throttling */
> +    io_limits.bps[BLOCK_IO_LIMIT_TOTAL]  =
> +                           qemu_opt_get_number(opts, "bps", 0);
> +    io_limits.bps[BLOCK_IO_LIMIT_READ]   =
> +                           qemu_opt_get_number(opts, "bps_rd", 0);
> +    io_limits.bps[BLOCK_IO_LIMIT_WRITE]  =
> +                           qemu_opt_get_number(opts, "bps_wr", 0);
> +    io_limits.iops[BLOCK_IO_LIMIT_TOTAL] =
> +                           qemu_opt_get_number(opts, "iops", 0);
> +    io_limits.iops[BLOCK_IO_LIMIT_READ]  =
> +                           qemu_opt_get_number(opts, "iops_rd", 0);
> +    io_limits.iops[BLOCK_IO_LIMIT_WRITE] =
> +                           qemu_opt_get_number(opts, "iops_wr", 0);
> +
> +    bps_iol  = (io_limits.bps[BLOCK_IO_LIMIT_TOTAL] != 0)
> +                 && ((io_limits.bps[BLOCK_IO_LIMIT_READ] != 0)
> +                 || (io_limits.bps[BLOCK_IO_LIMIT_WRITE] != 0));
> +    iops_iol = (io_limits.iops[BLOCK_IO_LIMIT_TOTAL] != 0)
> +                 && ((io_limits.iops[BLOCK_IO_LIMIT_READ] != 0)
> +                 || (io_limits.iops[BLOCK_IO_LIMIT_WRITE] != 0));
> +    if (bps_iol || iops_iol) {
> +        error_report("bps(iops) and bps_rd/bps_wr(iops_rd/iops_wr)"
> +                     "cannot be used at the same time");
> +        return NULL;
> +    }
> +


How about extracting this section into the bdrv_set_io_limits() function or some
other common setting function.  This should be the same code that's used when
modifying/setting these values via the monitor as well (minus how you obtain the
input values - option parsings vs. monitor values).

>      on_write_error = BLOCK_ERR_STOP_ENOSPC;
>      if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
>          if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type 
> != IF_NONE) {
> @@ -460,6 +489,9 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
> 
>      bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
> 
> +    /* disk I/O throttling */
> +    bdrv_set_io_limits(dinfo->bdrv, &io_limits);
> +
>      switch(type) {
>      case IF_IDE:
>      case IF_SCSI:
> diff --git a/qemu-config.c b/qemu-config.c
> index 597d7e1..1aa080f 100644
> --- a/qemu-config.c
> +++ b/qemu-config.c
> @@ -85,6 +85,30 @@ static QemuOptsList qemu_drive_opts = {
>              .name = "readonly",
>              .type = QEMU_OPT_BOOL,
>              .help = "open drive file as read-only",
> +        },{
> +            .name = "iops",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "limit total I/O operations per second",
> +        },{
> +            .name = "iops_rd",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "limit read operations per second",
> +        },{
> +            .name = "iops_wr",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "limit write operations per second",
> +        },{
> +            .name = "bps",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "limit total bytes per second",
> +        },{
> +            .name = "bps_rd",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "limit read bytes per second",
> +        },{
> +            .name = "bps_wr",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "limit write bytes per second",
>          },
>          { /* end of list */ }
>      },
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 681eaf1..25a7be7 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -136,6 +136,7 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive,
>      "       
> [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
>      "       [,serial=s][,addr=A][,id=name][,aio=threads|native]\n"
>      "       [,readonly=on|off]\n"
> +    "       
> [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]][[,iops=i]|[[,iops_rd=r][,iops_wr=w]]\n"
>      "                use 'file' as a drive image\n", QEMU_ARCH_ALL)
>  STEXI
>  @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
> -- 
> 1.7.6
> 

-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
address@hidden