From: "Trahe, Fiona" <fiona.trahe@intel.com>
To: "dev@dpdk.org" <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: [dpdk-dev] [PATCH] doc: add limitations section to cryptoperf guide
Date: Tue, 7 Feb 2017 16:32:55 +0000 [thread overview]
Message-ID: <348A99DA5F5B7549AA880327E580B43589182FE2@IRSMSX101.ger.corp.intel.com> (raw)
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
next reply other threads:[~2017-02-07 16:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-07 16:32 Trahe, Fiona [this message]
2017-02-08 9:31 ` Mrozowicz, SlawomirX
2017-02-08 9:47 ` Mrozowicz, SlawomirX
2017-02-09 23:24 ` De Lara Guarch, Pablo
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