Re: [PATCH v8 6/7] migration/multifd: implement qpl compression and decompression

[Fabiano Rosas]

Yuan Liu <yuan1.liu@intel.com> writes:

> QPL compression and decompression will use IAA hardware path if the IAA
> hardware is available. Otherwise the QPL library software path is used.
>
> The hardware path will automatically fall back to QPL software path if
> the IAA queues are busy. In some scenarios, this may happen frequently,
> such as configuring 4 channels but only one IAA device is available. In
> the case of insufficient IAA hardware resources, retry and fallback can
> help optimize performance:
>
>  1. Retry + SW fallback:
>     total time: 14649 ms
>     downtime: 25 ms
>     throughput: 17666.57 mbps
>     pages-per-second: 1509647
>
>  2. No fallback, always wait for work queues to become available
>     total time: 18381 ms
>     downtime: 25 ms
>     throughput: 13698.65 mbps
>     pages-per-second: 859607
>
> If both the hardware and software paths fail, the uncompressed page is
> sent directly.
>
> Signed-off-by: Yuan Liu <yuan1.liu@intel.com>
> Reviewed-by: Nanhai Zou <nanhai.zou@intel.com>
> ---
>  migration/multifd-qpl.c | 424 +++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 420 insertions(+), 4 deletions(-)
>
> diff --git a/migration/multifd-qpl.c b/migration/multifd-qpl.c
> index 6791a204d5..9265098ee7 100644
> --- a/migration/multifd-qpl.c
> +++ b/migration/multifd-qpl.c
> @@ -13,9 +13,14 @@
>  #include "qemu/osdep.h"
>  #include "qemu/module.h"
>  #include "qapi/error.h"
> +#include "qapi/qapi-types-migration.h"
> +#include "exec/ramblock.h"
>  #include "multifd.h"
>  #include "qpl/qpl.h"
>  
> +/* Maximum number of retries to resubmit a job if IAA work queues are full */
> +#define MAX_SUBMIT_RETRY_NUM (3)
> +
>  typedef struct {
>      /* the QPL hardware path job */
>      qpl_job *job;
> @@ -260,6 +265,225 @@ static void multifd_qpl_send_cleanup(MultiFDSendParams 
> *p, Error **errp)
>      p->iov = NULL;
>  }
>  
> +/**
> + * multifd_qpl_prepare_job: prepare the job
> + *
> + * Set the QPL job parameters and properties.
> + *
> + * @job: pointer to the qpl_job structure
> + * @is_compression: indicates compression and decompression
> + * @input: pointer to the input data buffer
> + * @input_len: the length of the input data
> + * @output: pointer to the output data buffer
> + * @output_len: the length of the output data
> + */
> +static void multifd_qpl_prepare_job(qpl_job *job, bool is_compression,
> +                                    uint8_t *input, uint32_t input_len,
> +                                    uint8_t *output, uint32_t output_len)
> +{
> +    job->op = is_compression ? qpl_op_compress : qpl_op_decompress;
> +    job->next_in_ptr = input;
> +    job->next_out_ptr = output;
> +    job->available_in = input_len;
> +    job->available_out = output_len;
> +    job->flags = QPL_FLAG_FIRST | QPL_FLAG_LAST | QPL_FLAG_OMIT_VERIFY;
> +    /* only supports compression level 1 */
> +    job->level = 1;
> +}
> +
> +/**
> + * multifd_qpl_prepare_comp_job: prepare the compression job
> + *
> + * Set the compression job parameters and properties.
> + *
> + * @job: pointer to the qpl_job structure
> + * @input: pointer to the input data buffer
> + * @output: pointer to the output data buffer
> + * @size: the page size
> + */
> +static void multifd_qpl_prepare_comp_job(qpl_job *job, uint8_t *input,
> +                                         uint8_t *output, uint32_t size)
> +{
> +    /*
> +     * Set output length to less than the page size to force the job to
> +     * fail in case it compresses to a larger size. We'll send that page
> +     * without compression and skip the decompression operation on the
> +     * destination.
> +     */

This is way better in here!

Reviewed-by: Fabiano Rosas <farosas@suse.de>