Re: [dpdk-dev] [PATCH v1 2/6] compress/zlib: add device setup PMD ops

["Daly, Lee" <lee.daly@intel.com>]

> >
> >> -----Original Message-----
> >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Shally Verma
> >> Sent: Tuesday, May 15, 2018 11:32 AM
> >> To: De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>
> >> Cc: Trahe, Fiona <fiona.trahe@intel.com>; dev@dpdk.org;
> >> pathreay@caviumnetworks.com; Sunila Sahu
> >> <sunila.sahu@caviumnetworks.com>; Ashish Gupta
> >> <ashish.gupta@caviumnetworks.com>
> >> Subject: [dpdk-dev] [PATCH v1 2/6] compress/zlib: add device setup
> >> PMD ops
> >>
> >>diff --git a/drivers/compress/zlib/zlib_pmd_ops.c
> >>b/drivers/compress/zlib/zlib_pmd_ops.c
> >>new file mode 100644
> >>index 0000000..0bd42f3
> >>--- /dev/null
> >>+++ b/drivers/compress/zlib/zlib_pmd_ops.c
> >>@@ -0,0 +1,238 @@
> >>+/* SPDX-License-Identifier: BSD-3-Clause
> >>+ * Copyright(c) 2018 Cavium Networks
> >>+ */
> >>+
> >>+#include <string.h>
> >>+
> >>+#include <rte_common.h>
> >>+#include <rte_malloc.h>
> >>+#include <rte_compressdev_pmd.h>
> >>+
> >>+#include "zlib_pmd_private.h"
> >>+
> >>+static const struct rte_compressdev_capabilities zlib_pmd_capabilities[]
> = {
> >>+      {   /* Deflate */
> >>+              .algo = RTE_COMP_ALGO_DEFLATE,
> >>+              .comp_feature_flags =
> RTE_COMP_FF_SHAREABLE_PRIV_XFORM,
> >[Lee] The priv_xform structure in this case is not shareable, as it
> >contains your zlib_stream structure, which contains zlibs own zstream
> >struct. This is not read only, the contents of this zstream will be written to,
> which means it is not shareable across queue pairs or devices.
> >
> [Shally] Per my understanding, SHAREABLE_PRIV_XFORM here means xform
> is shareable by all ops in one single enqueue_burst() but not across devices
> or qps by multiple threads in parallel. Does your implementation support
> such usage of shareable priv_xforms?
> 
> Thanks for review.
> Shally
[Lee]
Hey Shally, I have just clarified this with Fiona and Pablo and the intended use of Shareable priv xforms is to allow a xform to be shared across devices & qps not just all the ops in a burst, yes the ISA-L PMD has a shareable private xform due to all its contents being read only. 

> 
> >>+              .window_size = {
> >>+                      .min = 8,
> >>+                      .max = 15,
> >>+                      .increment = 2
> >>+              },
> >>+      },
> >>+
> >>+      RTE_COMP_END_OF_CAPABILITIES_LIST()
> >>+