diff mbox

[dpdk-dev] doc: add limitations section to cryptoperf guide

Message ID 348A99DA5F5B7549AA880327E580B43589182FE2@IRSMSX101.ger.corp.intel.com (mailing list archive)
State Accepted, archived
Delegated to: Pablo de Lara Guarch
Headers

Checks

Context Check Description
ci/checkpatch warning coding style issues
ci/Intel compilation fail Compilation issues

Commit Message

Fiona Trahe Feb. 7, 2017, 4:32 p.m. UTC 
  Add limitations to use of the dpdk-test-crypto-perf 
tool for hardware accelerator measurements

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 doc/guides/tools/cryptoperf.rst |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

Comments

Slawomir Mrozowicz Feb. 8, 2017, 9:31 a.m. UTC | #1 
>-----Original Message-----
>From: Trahe, Fiona
>Sent: Tuesday, February 7, 2017 5:33 PM
>To: dev@dpdk.org
>Cc: De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>; Mrozowicz,
>SlawomirX <slawomirx.mrozowicz@intel.com>; Jain, Deepak K
><deepak.k.jain@intel.com>; Trahe, Fiona <fiona.trahe@intel.com>; Griffin,
>John <john.griffin@intel.com>; Doherty, Declan <declan.doherty@intel.com>
>Subject: [PATCH] doc: add limitations section to cryptoperf guide
>
>Add limitations to use of the dpdk-test-crypto-perf tool for hardware
>accelerator measurements
>
>Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
>---
> doc/guides/tools/cryptoperf.rst |   16 ++++++++++++++++
> 1 files changed, 16 insertions(+), 0 deletions(-)
>
>diff --git a/doc/guides/tools/cryptoperf.rst b/doc/guides/tools/cryptoperf.rst
>index 6832312..af58e78 100644
>--- a/doc/guides/tools/cryptoperf.rst
>+++ b/doc/guides/tools/cryptoperf.rst
>@@ -41,6 +41,22 @@ chain mode have to be specified in the command line as
>application  parameters. These parameters are checked using device
>capabilities  structure.
>
>+Limitations:
>+------------
>+On hardware devices the cycle-count doesn't always represent the actual
>+offload cost. The cycle-count only represents the offload cost when the
>+hardware accelerator is not fully loaded, when loaded the cpu cycles
>+freed up by the offload are still consumed by the test tool and included in
>the cycle-count.
>+These cycles are consumed by retries and inefficient API calls
>+enqueuing and dequeuing smaller bursts than specified by the cmdline
>+parameter. This results in a larger cycle-count measurement and should
>+not be interpreted as an offload cost measurement.
>+
>+On hardware devices the throughput measurement is not necessarily the
>+maximum possible for the device, e.g. it may be necessary to use
>+multiple cores to keep the hardware accelerator fully loaded and so measure
>maximum throughput.
>+
>+
> Compiling the Application
> -------------------------
>
>--
>1.7.0.7

From my point of view this information is ok.
Sławomir
Slawomir Mrozowicz Feb. 8, 2017, 9:47 a.m. UTC | #2 
>-----Original Message-----
>From: Trahe, Fiona
>Sent: Tuesday, February 7, 2017 5:33 PM
>To: dev@dpdk.org
>Cc: De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>; Mrozowicz,
>SlawomirX <slawomirx.mrozowicz@intel.com>; Jain, Deepak K
><deepak.k.jain@intel.com>; Trahe, Fiona <fiona.trahe@intel.com>; Griffin,
>John <john.griffin@intel.com>; Doherty, Declan <declan.doherty@intel.com>
>Subject: [PATCH] doc: add limitations section to cryptoperf guide
>
>Add limitations to use of the dpdk-test-crypto-perf tool for hardware
>accelerator measurements
>
>Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
>---
> doc/guides/tools/cryptoperf.rst |   16 ++++++++++++++++
> 1 files changed, 16 insertions(+), 0 deletions(-)
>
>diff --git a/doc/guides/tools/cryptoperf.rst b/doc/guides/tools/cryptoperf.rst
>index 6832312..af58e78 100644
>--- a/doc/guides/tools/cryptoperf.rst
>+++ b/doc/guides/tools/cryptoperf.rst
>@@ -41,6 +41,22 @@ chain mode have to be specified in the command line as
>application  parameters. These parameters are checked using device
>capabilities  structure.
>
>+Limitations:
>+------------
>+On hardware devices the cycle-count doesn't always represent the actual
>+offload cost. The cycle-count only represents the offload cost when the
>+hardware accelerator is not fully loaded, when loaded the cpu cycles
>+freed up by the offload are still consumed by the test tool and included in
>the cycle-count.
>+These cycles are consumed by retries and inefficient API calls
>+enqueuing and dequeuing smaller bursts than specified by the cmdline
>+parameter. This results in a larger cycle-count measurement and should
>+not be interpreted as an offload cost measurement.
>+
>+On hardware devices the throughput measurement is not necessarily the
>+maximum possible for the device, e.g. it may be necessary to use
>+multiple cores to keep the hardware accelerator fully loaded and so measure
>maximum throughput.
>+
>+
> Compiling the Application
> -------------------------
>
>--
>1.7.0.7

Acked-by: Slawomir Mrozowicz <slawomirx.mrozowicz@intel.com>
De Lara Guarch, Pablo Feb. 9, 2017, 11:24 p.m. UTC | #3 
> -----Original Message-----
> From: Mrozowicz, SlawomirX
> Sent: Wednesday, February 08, 2017 9:48 AM
> To: Trahe, Fiona; dev@dpdk.org
> Cc: De Lara Guarch, Pablo; Jain, Deepak K; Griffin, John; Doherty, Declan
> Subject: RE: [PATCH] doc: add limitations section to cryptoperf guide
> 
> 
> 
> >-----Original Message-----
> >From: Trahe, Fiona
> >Sent: Tuesday, February 7, 2017 5:33 PM
> >To: dev@dpdk.org
> >Cc: De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>; Mrozowicz,
> >SlawomirX <slawomirx.mrozowicz@intel.com>; Jain, Deepak K
> ><deepak.k.jain@intel.com>; Trahe, Fiona <fiona.trahe@intel.com>; Griffin,
> >John <john.griffin@intel.com>; Doherty, Declan
> <declan.doherty@intel.com>
> >Subject: [PATCH] doc: add limitations section to cryptoperf guide
> >
> >Add limitations to use of the dpdk-test-crypto-perf tool for hardware
> >accelerator measurements
> >
> >Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>

...
 
> Acked-by: Slawomir Mrozowicz <slawomirx.mrozowicz@intel.com>

Applied to dpdk-next-crypto.
Thanks,

Pablo
diff mbox

Patch

diff --git a/doc/guides/tools/cryptoperf.rst b/doc/guides/tools/cryptoperf.rst
index 6832312..af58e78 100644
--- a/doc/guides/tools/cryptoperf.rst
+++ b/doc/guides/tools/cryptoperf.rst
@@ -41,6 +41,22 @@  chain mode have to be specified in the command line as application
 parameters. These parameters are checked using device capabilities
 structure.
 
+Limitations:
+------------
+On hardware devices the cycle-count doesn't always represent the actual offload
+cost. The cycle-count only represents the offload cost when the hardware
+accelerator is not fully loaded, when loaded the cpu cycles freed up by the
+offload are still consumed by the test tool and included in the cycle-count.
+These cycles are consumed by retries and inefficient API calls enqueuing and
+dequeuing smaller bursts than specified by the cmdline parameter. This results
+in a larger cycle-count measurement and should not be interpreted as an offload
+cost measurement.
+
+On hardware devices the throughput measurement is not necessarily the maximum
+possible for the device, e.g. it may be necessary to use multiple cores to keep
+the hardware accelerator fully loaded and so measure maximum throughput.
+
+
 Compiling the Application
 -------------------------