[Spice-devel] [spice-gtk PATCH] Usbredir: enable lz4 compression

Victor Toso lists at victortoso.com
Mon Apr 4 09:39:52 UTC 2016


Hi,

You'll need to rebase this series to latest master. Both spice-gtk and
spice-server patches don't apply.

On Sun, Apr 03, 2016 at 06:40:09PM +0300, Snir Sheriber wrote:
> Compressed message type is CompressedData which contains compression
> type (1 byte) followed by the uncompressed data size (4 bytes) followed
> by the compressed data size (4 bytes) followed by the compressed data
>
> If SPICE_SPICEVMC_CAP_DATA_COMPRESS_LZ4 capability is available &&
> data_size > COMPRESS_THRESHOLD data will be sent compressed otherwise
> data will be sent uncompressed (as well if compression has failed)
> ---
>  src/channel-usbredir.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 89 insertions(+), 7 deletions(-)
>
> diff --git a/src/channel-usbredir.c b/src/channel-usbredir.c
> index d95a6c5..cd5cebd 100644
> --- a/src/channel-usbredir.c
> +++ b/src/channel-usbredir.c
> @@ -24,6 +24,9 @@
>  #ifdef USE_USBREDIR
>  #include <glib/gi18n.h>
>  #include <usbredirhost.h>
> +#ifdef USE_LZ4
> +#include <lz4.h>
> +#endif
>  #ifdef USE_POLKIT
>  #include "usb-acl-helper.h"
>  #endif
> @@ -52,6 +55,7 @@
>  
>  #ifdef USE_USBREDIR
>  
> +#define COMPRESS_THRESHOLD 1000

Why the threshold is 1000?

>  #define SPICE_USBREDIR_CHANNEL_GET_PRIVATE(obj)                                  \
>      (G_TYPE_INSTANCE_GET_PRIVATE((obj), SPICE_TYPE_USBREDIR_CHANNEL, SpiceUsbredirChannelPrivate))
>  
> @@ -195,6 +199,8 @@ static void channel_set_handlers(SpiceChannelClass *klass)
>  {
>      static const spice_msg_handler handlers[] = {
>          [ SPICE_MSG_SPICEVMC_DATA ] = usbredir_handle_msg,
> +        [ SPICE_MSG_SPICEVMC_COMPRESSED_DATA ] = usbredir_handle_msg,
> +
>      };
>  
>      spice_channel_set_handlers(klass, handlers, G_N_ELEMENTS(handlers));
> @@ -231,6 +237,9 @@ void spice_usbredir_channel_set_context(SpiceUsbredirChannel *channel,
>  #if USBREDIR_VERSION >= 0x000701
>      usbredirhost_set_buffered_output_size_cb(priv->host, usbredir_buffered_output_size_callback);
>  #endif
> +#ifdef USE_LZ4
> +    spice_channel_set_capability(channel, SPICE_SPICEVMC_CAP_DATA_COMPRESS_LZ4);
> +#endif
>  }
>  
>  static gboolean spice_usbredir_channel_open_device(
> @@ -544,11 +553,52 @@ static void usbredir_free_write_cb_data(uint8_t *data, void *user_data)
>      usbredirhost_free_write_buffer(priv->host, data);
>  }
>  
> +#ifdef USE_LZ4
> +static void usbredir_free_write_cb_compressed_data(uint8_t *data, void *user_data)
> +{
> +    SpiceUsbredirChannel *channel = user_data;
> +    SpiceUsbredirChannelPrivate *priv = channel->priv;
> +
> +    usbredirhost_free_write_buffer(priv->host, (uint8_t*)SPICE_CONTAINEROF(data, SpiceMsgCompressedData, compressed_data));
> +}
> +#endif
> +
>  static int usbredir_write_callback(void *user_data, uint8_t *data, int count)
>  {
>      SpiceUsbredirChannel *channel = user_data;
>      SpiceMsgOut *msg_out;
> -
> +#ifdef USE_LZ4
> +    int bound;
> +
> +    if(count > COMPRESS_THRESHOLD &&
> +                                spice_channel_test_capability(SPICE_CHANNEL(channel),
> +                                SPICE_SPICEVMC_CAP_DATA_COMPRESS_LZ4) &&
> +                                ((bound = LZ4_compressBound(count)) != 0)) {
> +        int compressed_data_count;
> +        SpiceMsgCompressedData *compressed_data_msg;
> +
> +        compressed_data_msg = (SpiceMsgCompressedData*)spice_malloc(sizeof(SpiceMsgCompressedData) + bound);
> +        compressed_data_msg->uncompressed_size = count;
> +        compressed_data_msg->type = SPICE_DATA_COMPRESSION_TYPE_LZ4;
> +        compressed_data_count = LZ4_compress_default((char*)data,
> +                                (char*)compressed_data_msg->compressed_data, count, bound);
> +        if (compressed_data_count > 0) {
> +            compressed_data_msg->compressed_size = compressed_data_count;
> +            msg_out = spice_msg_out_new(SPICE_CHANNEL(channel),
> +                                    SPICE_MSGC_SPICEVMC_COMPRESSED_DATA);
> +            msg_out->marshallers->msg_SpiceMsgCompressedData(msg_out->marshaller, compressed_data_msg);
> +            spice_marshaller_add_ref_full(msg_out->marshaller,
> +                                          (uint8_t*)compressed_data_msg->compressed_data,
> +                                          compressed_data_count,
> +                                          usbredir_free_write_cb_compressed_data,
> +                                          channel);
> +            spice_msg_out_send(msg_out);
> +            return count;
> +        } else {/* free & fallback to sending the message uncompressed */
> +            free(compressed_data_msg);
> +        }
> +    }
> +#endif

Make this in a new function that will do the checks, compress and send the data.

>      msg_out = spice_msg_out_new(SPICE_CHANNEL(channel),
>                                  SPICE_MSGC_SPICEVMC_DATA);
>      spice_marshaller_add_ref_full(msg_out->marshaller, data, count,
> @@ -639,19 +689,51 @@ static void usbredir_handle_msg(SpiceChannel *c, SpiceMsgIn *in)
>      SpiceUsbredirChannel *channel = SPICE_USBREDIR_CHANNEL(c);
>      SpiceUsbredirChannelPrivate *priv = channel->priv;
>      device_error_data data;
> -    int r, size;
> -    uint8_t *buf;
> +    int r = 0;
>
>      g_return_if_fail(priv->host != NULL);
>
>      /* No recursion allowed! */
>      g_return_if_fail(priv->read_buf == NULL);
>
> -    buf = spice_msg_in_raw(in, &size);
> -    priv->read_buf = buf;
> -    priv->read_buf_size = size;
> +    if (spice_msg_in_type(in) == SPICE_MSG_SPICEVMC_COMPRESSED_DATA) {
> +        SpiceMsgCompressedData *compressed_data_msg = spice_msg_in_parsed(in);
> +        uint32_t decompressed_size = 0;
> +        char* decompressed;
> +
> +        switch(compressed_data_msg->type) {
> +#ifdef USE_LZ4
> +        case SPICE_DATA_COMPRESSION_TYPE_LZ4:
> +            decompressed = (char*)malloc(compressed_data_msg->uncompressed_size);
> +            decompressed_size = LZ4_decompress_safe ((char*)compressed_data_msg->compressed_data,
> +                                                     decompressed,
> +                                                     compressed_data_msg->compressed_size,
> +                                                     compressed_data_msg->uncompressed_size);
> +            break;
> +#endif
> +        default:
> +            decompressed = NULL;
> +            g_warning("Unknown Compression Type");

I would go with spice_warning

> +            r = usbredirhost_read_parse_error;
> +        }
> +        if (decompressed_size != compressed_data_msg->uncompressed_size) {
> +            g_warning("Decompress Error decompressed_size=%d expected=%d",
> +                      decompressed_size, compressed_data_msg->uncompressed_size);
> +            r = usbredirhost_read_parse_error;
> +        } else {
> +            priv->read_buf_size = decompressed_size;
> +            priv->read_buf = (uint8_t*)decompressed;
> +        }

I would also do this recv/decompress bits in a function elsewere.
Both functions, compress/send and recv/decompress could then be
surrounded by #ifdef USE_LZ4

> +    } else { /*Regular SPICE_MSG_SPICEVMC_DATA msg*/
> +        int size;
> +        uint8_t *buf;
> +        buf = spice_msg_in_raw(in, &size);
> +        priv->read_buf_size = size;
> +        priv->read_buf = buf;
> +    }
>  
> -    r = usbredirhost_read_guest_data(priv->host);
> +    if (r == 0)
> +        r = usbredirhost_read_guest_data(priv->host);
>      if (r != 0) {
>          SpiceUsbDevice *spice_device = priv->spice_device;
>          gchar *desc;
> -- 
> 2.4.11
> 
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