i386/i586/i686

[arun_maurya]

Does there any difference in kernel.i586 and kernel.i686 package? some packages are installed as i386, some as i586 and some like kernel as i686.

I have Intel P4 with HT. Which arch (i386/i586/i686) packages are best for my system?



Example:
Presently my system has by default installed :
kernel-headers.i386
kernel.i686

i can't find kernel-headers.i686.


regards,

[notageek]

As far as I know packages which end with i386 are optimized to run on at-least Intel 80*386 CPU, which means that that particular binary will run well on any box which has a processor higher that i386.

Similarly packages with i586 suffix are optimized for "Pentium" class processors (starting from Pentium 1).

More info on that here http://en.wikipedia.org/wiki/I586

i686 are also Pentium class processors, however they corresponds to 6th generation Intel x86 Microprossor.

More on that here http://en.wikipedia.org/wiki/I686

Packages optimized for these archs means that they were compiled on a cpu with the corresponding cpu, to fully utilize the instruction set available for each generation of CPU.

To the best of my knowledge, this is what is meant by i386,i586 etc packages.

[arun_maurya]

Thanks notageek,

So for P4 processor we should use i686 packages.

I want to know is there any performance issue if i install a binary package compiled with i386 instead of i686 on my machine?

[notageek]

Packages optimized for i686 is faster than i586 is faster than i486 is faster than i386.

CPUs earlier than i486 didn't have a built in math co-processor, hence it was emulated in software, hence making it slower.

i586 and later have math co-processor and hence faster.

[marcrblevins]

I wouldn't worry about seeing i386 installed all over the the place.

If you see a package you like, try "yum search yourpackagename" it would show mostly i386, and possible not i686 etc.

I use:
yum search httpd

Got, all shown i386:
[root@kiriyamablevins ~]# yum search httpdLoaded plugins: refresh-packagekit======================================== ============================== Matched: httpd ================================================== =====================mod_ssl.i386 : SSL/TLS module for the Apache HTTP Serversystem-config-httpd.noarch : Apache configuration toolfedora-ds.i386 : Red Hat Directory, Administration, and Console Suitehttpd.i386 : Apache HTTP Serverhttpd-devel.i386 : Development interfaces for the Apache HTTP serverhttpd-manual.i386 : Documentation for the Apache HTTP serverhttpd-tools.i386 : Tools for use with the Apache HTTP Serverlibapreq2.i386 : Apache HTTP request librarylibapreq2-devel.i386 : Development files for libapreq2lighttpd.i386 : Lightning fast webserver with light system requirementslighttpd-fastcgi.i386 : FastCGI module and spawning helper for lighttpd and PHP configurationlighttpd-mod_geoip.i386 : GeoIP module for lighttpd to use for location lookupslighttpd-mod_mysql_vhost.i386 : Virtual host module for lighttpd that uses a MySQL databasemantis-config-httpd.noarch : Mantis configuration for Apache httpdmod_dav_svn.i386 : Apache server module for Subversion servermod_dnssd.i386 : An Apache HTTPD module which adds Zeroconf supportmogstored-backend-lighttpd.noarch : LigHTTPd backend for mogstoredocaml-ocamlnet.i386 : Network protocols for OCamlocaml-ocamlnet-nethttpd.i386 : Ocamlnet HTTP daemonocaml-ocamlnet-nethttpd-devel.i386 : Development files for ocaml-ocamlnet-nethttpdperl-Apache-Session.noarch : Persistence framework for session dataperl-POE-Component-Server-HTTP.noarch : Foundation of a POE HTTP Daemonperl-libapreq2.i386 : Perl interface to the Apache HTTP request libraryphpldapadmin.noarch : Web-based tool for managing LDAP serversphpwapmail.noarch : WAP-based e-mail clienttclhttpd.i386 : Extensible Web+Application server written in Tclthttpd.i386 : Tiny, turbo, throttleable lightweight http server[root@kiriyamablevins ~]#