| Message ID | 1471199749-9378-3-git-send-email-bhanuprakash.bodireddy@intel.com |
|---|---|
| State | Rejected |
| Delegated to: | Daniele Di Proietto |
| Headers | show |
By default we do not want to build Open vSwitch for a particular CPU, we want to create a build that can be distributed to every CPU of the architecture (e.g. amd64). Unfortunately, this not entirely possible for with DPDK, because rte_memcpy (included by the headers in netdev-dpdk) requires SSSE3. The 'default' machine in DPDK (which, if I'm not mistaken, should produce the most distributable build) does not work on every amd64, but requires -march=core2, i.e. -mssse3. We shouldn't change this unless OvS+DPDK cannot work without sse4.2. I don't think this is the case, right? Thanks, Daniele 2016-08-14 11:35 GMT-07:00 Bhanuprakash Bodireddy < bhanuprakash.bodireddy@intel.com>: > On processors with SSE4.2 instruction set support, CRC32 intrinsics can > be used for efficient hash computation. > > Update the m4_translit to convert '.' to '_' that otherwise cause 'bad > substitution' error when configuring OVS DPDK with msse4.2 support. > > ./configure: line 21027: ${ovs_cv__msse4.2+:}: bad substitution > > Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> > --- > acinclude.m4 | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/acinclude.m4 b/acinclude.m4 > index aa57b47..93c7a5a 100644 > --- a/acinclude.m4 > +++ b/acinclude.m4 > @@ -280,7 +280,7 @@ AC_DEFUN([OVS_CHECK_DPDK], [ > OVS_LDFLAGS="$OVS_LDFLAGS -L$DPDK_LIB_DIR" > fi > OVS_CFLAGS="$OVS_CFLAGS -I$DPDK_INCLUDE" > - OVS_ENABLE_OPTION([-mssse3]) > + OVS_ENABLE_OPTION([-msse4.2]) > > # DPDK pmd drivers are not linked unless --whole-archive is used. > # > @@ -776,7 +776,7 @@ dnl gives unlimited permission to copy and/or > distribute it, > dnl with or without modifications, as long as this notice is preserved. > > AC_DEFUN([_OVS_CHECK_CC_OPTION], [dnl > - m4_define([ovs_cv_name], [ovs_cv_[]m4_translit([$1], [-=], [__])])dnl > + m4_define([ovs_cv_name], [ovs_cv_[]m4_translit([$1], [-=.], [___])])dnl > AC_CACHE_CHECK([whether $CC accepts $1], [ovs_cv_name], > [ovs_save_CFLAGS="$CFLAGS" > dnl Include -Werror in the compiler options, because without -Werror > -- > 2.4.11 > > _______________________________________________ > dev mailing list > dev@openvswitch.org > http://openvswitch.org/mailman/listinfo/dev >
Thanks for looking in to this Daniele, My comments inline. >-----Original Message----- >From: Daniele Di Proietto [mailto:diproiettod@ovn.org] >Sent: Sunday, August 14, 2016 9:13 PM >To: Bodireddy, Bhanuprakash <bhanuprakash.bodireddy@intel.com> >Cc: dev@openvswitch.org >Subject: Re: [ovs-dev] [PATCH 3/3] acinclude: Use SSE4.2 instruction set > >By default we do not want to build Open vSwitch for a particular CPU, we >want to create a build that can be distributed to every CPU of the architecture >(e.g. amd64). >Unfortunately, this not entirely possible for with DPDK, because rte_memcpy >(included by the headers in netdev-dpdk) requires SSSE3. The 'default' >machine in DPDK (which, if I'm not mistaken, should produce the most >distributable build) does not work on every amd64, but requires - >march=core2, i.e. -mssse3. I got the reason behind using mssse3 from the previous discussions on the Mailing list. >We shouldn't change this unless OvS+DPDK cannot work without sse4.2. I >don't think this is the case, right? With out sse4.2, OVS DPDK uses murmur hash for hash computation. I found that performance is better using crc32 intrinsics instead of murmurhash3. OVS DPDK is configured with SSSE3 by default and thought to override this with the patch. But I agree with your suggestion. Anyways we have a note in INSTALL.md on msse4.2 and that should help users looking to leverage built-in Intrinsics. Regards, Bhanu Prakash. >Thanks, >Daniele > >2016-08-14 11:35 GMT-07:00 Bhanuprakash Bodireddy ><bhanuprakash.bodireddy@intel.com>: >On processors with SSE4.2 instruction set support, CRC32 intrinsics can >be used for efficient hash computation. > >Update the m4_translit to convert '.' to '_' that otherwise cause 'bad >substitution' error when configuring OVS DPDK with msse4.2 support. > > ./configure: line 21027: ${ovs_cv__msse4.2+:}: bad substitution > >Signed-off-by: Bhanuprakash Bodireddy ><bhanuprakash.bodireddy@intel.com> >--- > acinclude.m4 | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > >diff --git a/acinclude.m4 b/acinclude.m4 >index aa57b47..93c7a5a 100644 >--- a/acinclude.m4 >+++ b/acinclude.m4 >@@ -280,7 +280,7 @@ AC_DEFUN([OVS_CHECK_DPDK], [ > OVS_LDFLAGS="$OVS_LDFLAGS -L$DPDK_LIB_DIR" > fi > OVS_CFLAGS="$OVS_CFLAGS -I$DPDK_INCLUDE" >- OVS_ENABLE_OPTION([-mssse3]) >+ OVS_ENABLE_OPTION([-msse4.2]) > > # DPDK pmd drivers are not linked unless --whole-archive is used. > # >@@ -776,7 +776,7 @@ dnl gives unlimited permission to copy and/or >distribute it, > dnl with or without modifications, as long as this notice is preserved. > > AC_DEFUN([_OVS_CHECK_CC_OPTION], [dnl >- m4_define([ovs_cv_name], [ovs_cv_[]m4_translit([$1], [-=], [__])])dnl >+ m4_define([ovs_cv_name], [ovs_cv_[]m4_translit([$1], [-=.], [___])])dnl > AC_CACHE_CHECK([whether $CC accepts $1], [ovs_cv_name], > [ovs_save_CFLAGS="$CFLAGS" > dnl Include -Werror in the compiler options, because without -Werror >-- >2.4.11 > >_______________________________________________ >dev mailing list >dev@openvswitch.org >http://openvswitch.org/mailman/listinfo/dev
diff --git a/acinclude.m4 b/acinclude.m4 index aa57b47..93c7a5a 100644 --- a/acinclude.m4 +++ b/acinclude.m4 @@ -280,7 +280,7 @@ AC_DEFUN([OVS_CHECK_DPDK], [ OVS_LDFLAGS="$OVS_LDFLAGS -L$DPDK_LIB_DIR" fi OVS_CFLAGS="$OVS_CFLAGS -I$DPDK_INCLUDE" - OVS_ENABLE_OPTION([-mssse3]) + OVS_ENABLE_OPTION([-msse4.2]) # DPDK pmd drivers are not linked unless --whole-archive is used. # @@ -776,7 +776,7 @@ dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([_OVS_CHECK_CC_OPTION], [dnl - m4_define([ovs_cv_name], [ovs_cv_[]m4_translit([$1], [-=], [__])])dnl + m4_define([ovs_cv_name], [ovs_cv_[]m4_translit([$1], [-=.], [___])])dnl AC_CACHE_CHECK([whether $CC accepts $1], [ovs_cv_name], [ovs_save_CFLAGS="$CFLAGS" dnl Include -Werror in the compiler options, because without -Werror
On processors with SSE4.2 instruction set support, CRC32 intrinsics can be used for efficient hash computation. Update the m4_translit to convert '.' to '_' that otherwise cause 'bad substitution' error when configuring OVS DPDK with msse4.2 support. ./configure: line 21027: ${ovs_cv__msse4.2+:}: bad substitution Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> --- acinclude.m4 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)