[ovs-dev] [PATCH] INSTALL: Note about compiler atomics support.
Jarno Rajahalme
jrajahalme at nicira.com
Wed Jun 4 16:38:09 UTC 2014
Pushed, thanks.
Jarno
On Jun 3, 2014, at 11:38 PM, YAMAMOTO Takashi <yamamoto at valinux.co.jp> wrote:
>> OVS is slow when compiled with pthreads atomics. Add a generic note
>> in INSTALL, with a reference to lib/ovs-atomic.h, where a new comment
>> provides additional detail.
>>
>> Signed-off-by: Jarno Rajahalme <jrajahalme at nicira.com>
>
> Acked-by: YAMAMOTO Takashi <yamamoto at valinux.co.jp>
>
>> ---
>> INSTALL | 4 ++++
>> lib/ovs-atomic.h | 3 +++
>> 2 files changed, 7 insertions(+)
>>
>> diff --git a/INSTALL b/INSTALL
>> index 5c869b2..7b08172 100644
>> --- a/INSTALL
>> +++ b/INSTALL
>> @@ -28,6 +28,10 @@ you will need the following software:
>> analysis and thread-safety checks. For Ubuntu, there are
>> nightly built packages available on clang's website.
>>
>> + * While OVS may be compatible with other compilers, optimal
>> + support for atomic operations may be missing, making OVS
>> + very slow (see lib/ovs-atomic.h).
>> +
>> - libssl, from OpenSSL, is optional but recommended if you plan to
>> connect the Open vSwitch to an OpenFlow controller. libssl is
>> required to establish confidentiality and authenticity in the
>> diff --git a/lib/ovs-atomic.h b/lib/ovs-atomic.h
>> index c21b7ee..2452846 100644
>> --- a/lib/ovs-atomic.h
>> +++ b/lib/ovs-atomic.h
>> @@ -257,6 +257,9 @@
>> #elif HAVE_GCC4_ATOMICS
>> #include "ovs-atomic-gcc4+.h"
>> #else
>> + /* ovs-atomic-pthreads implementation is provided for portability.
>> + * It might be too slow for real use because Open vSwitch is
>> + * optimized for platforms where real atomic ops are available. */
>> #include "ovs-atomic-pthreads.h"
>> #endif
>> #undef IN_OVS_ATOMIC_H
>> --
>> 1.7.10.4
>>
>> _______________________________________________
>> dev mailing list
>> dev at openvswitch.org
>> http://openvswitch.org/mailman/listinfo/dev
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