= strlen =

== Variants ==

||= '''Name''' =||= '''Description''' =||
|| stock || MD amd64 version {{rep stosq}} ||
|| SSE2 || {{{movdqu}}} for block-store ||
|| SSE2 aligned || {{{movaps}}} for aligned block-store and {{{movdqu}}} for unaligned ||
|| AVX 128 || 128-bit {{{vmovdqu}}} for block-store ||
|| AVX 256 || 256-bit {{{vmovdqu}}} for block-store ||
|| ERMS || {{{repne stosb}}} for machines with ERMS ||

== Machines Tested ==

||= '''CPU''' =||= '''Speed (GHz)''' =||= '''Notes''' =||
|| AMD FX-8120 || 3.11 || 1 x 8 zoo.freebsd.org ||
|| AMD Opteron 6328 || 3.20 || 2 x 8 Supermicro H8DG6/H8DGi ||
|| Intel Xeon X5365 || 3.00 || 2 x 4 Supermicro X7DBU ||
|| Intel Xeon X5482 || 3.20 || 2 x 4 Supermicro X7DWN+ ||
|| Intel Xeon X5675 || 3.07 || Westmere 2 x 6 Supermicro X8DTU ||
|| Intel Core i5-2520M || 2.50 || Sandy Bridge 1 x 4 Thinkpad X220 (4286) ||
|| Intel Core i5-2500K || 3.30 || Sandy Bridge 1 x 4 MSI Z77A-G45 (MS-7752) ||
|| Intel Xeon E5-2680 || 2.70 || Romley 2 x 8 Supermicro X9DRW ||
|| Intel Xeon E5-2667 v2 || 3.30 || Romley V2 2 x 8 Supermicro X9DRW (supports ERMS) ||

== Test Cases ==

||= '''Name''' =||= '''Description''' =||
|| page || set page to 0xa5 ||
|| short || set aligned 15 bytes to 0xa5 ||
|| short2 || set aligned 32 bytes to 0xa5 ||
|| short3 || set aligned 48 bytes to 0xa5 ||
|| offset || set misaligned ( + 4) 128 bytes to 0 ||
|| offset2 || set misaligned ( + 7) 97 bytes to 0 ||

== Results ==

The numbers are the min value in the distribution where the values are a TSC delta across a single invocation of the test.

Bold indicates the lowest time among the given variations in a Test and CPU combination.  Green text is used for times faster than the stock implementation, and red text is used for times slower than the stock implementation.

{{{#!th rowspan=3
'''CPU'''
}}}
{{{#!th colspan=36
'''Test / Variant'''
}}}
|--
{{{#!th colspan=6
'''page'''
}}}
{{{#!th colspan=6
'''short'''
}}}
{{{#!th colspan=6
'''short2'''
}}}
{{{#!th colspan=6
'''short3'''
}}}
{{{#!th colspan=6
'''offset'''
}}}
{{{#!th colspan=6
'''offset2'''
}}}
|--
||= '''stock''' =||= '''SSE2''' =||= '''SSSE2 aligned''' =||= '''AVX 128''' =||= '''AVX 256''' =||= '''ERMS''' =|| \
||= '''stock''' =||= '''SSE2''' =||= '''SSSE2 aligned''' =||= '''AVX 128''' =||= '''AVX 256''' =||= '''ERMS''' =|| \
||= '''stock''' =||= '''SSE2''' =||= '''SSSE2 aligned''' =||= '''AVX 128''' =||= '''AVX 256''' =||= '''ERMS''' =|| \
||= '''stock''' =||= '''SSE2''' =||= '''SSSE2 aligned''' =||= '''AVX 128''' =||= '''AVX 256''' =||= '''ERMS''' =|| \
||= '''stock''' =||= '''SSE2''' =||= '''SSSE2 aligned''' =||= '''AVX 128''' =||= '''AVX 256''' =||= '''ERMS''' =|| \
||= '''stock''' =||= '''SSE2''' =||= '''SSSE2 aligned''' =||= '''AVX 128''' =||= '''AVX 256''' =||= '''ERMS''' =||
|| AMD FX-8120 || \
|| 663|| [[span(601, style=color: green)]]|| '''[[span(404, style=color: green)]]'''|| [[span(405, style=color: green)]]|| [[span(1886, style=color:red)]]|| [[span(1018, style=color:red)]]|| \
|| '''49'''|| [[span(98, style=color:red)]]|| [[span(64, style=color:red)]]|| [[span(64, style=color:red)]]|| [[span(95, style=color:red)]]|| [[span(153, style=color:red)]]|| \
|| 49|| [[span(52, style=color:red)]]|| '''[[span(38, style=color: green)]]'''|| [[span(39, style=color: green)]]|| [[span(55, style=color:red)]]|| [[span(243, style=color:red)]]|| \
|| 49|| [[span(55, style=color:red)]]|| 49|| '''[[span(43, style=color: green)]]'''|| [[span(72, style=color:red)]]|| [[span(292, style=color:red)]]|| \
|| 51|| [[span(56, style=color:red)]]|| '''[[span(43, style=color: green)]]'''|| [[span(44, style=color: green)]]|| [[span(90, style=color:red)]]|| [[span(469, style=color:red)]]|| \
|| 52|| [[span(74, style=color:red)]]|| 52|| '''[[span(49, style=color: green)]]'''|| [[span(88, style=color:red)]]|| [[span(469, style=color:red)]]||
|| AMD Opteron 6328 || \
|| 482|| [[span(443, style=color: green)]]|| '''[[span(424, style=color: green)]]'''|| [[span(461, style=color: green)]]|| [[span(2454, style=color:red)]]|| [[span(449, style=color: green)]]|| \
|| '''69'''|| [[span(106, style=color:red)]]|| [[span(106, style=color:red)]]|| [[span(106, style=color:red)]]|| [[span(106, style=color:red)]]|| [[span(106, style=color:red)]]|| \
|| '''68'''|| [[span(87, style=color:red)]]|| [[span(88, style=color:red)]]|| [[span(86, style=color:red)]]|| [[span(87, style=color:red)]]|| [[span(128, style=color:red)]]|| \
|| '''66'''|| [[span(90, style=color:red)]]|| [[span(92, style=color:red)]]|| [[span(90, style=color:red)]]|| [[span(89, style=color:red)]]|| [[span(151, style=color:red)]]|| \
|| 102|| '''[[span(89, style=color: green)]]'''|| [[span(95, style=color: green)]]|| [[span(95, style=color: green)]]|| [[span(99, style=color: green)]]|| [[span(230, style=color:red)]]|| \
|| 104|| '''[[span(92, style=color: green)]]'''|| [[span(93, style=color: green)]]|| [[span(93, style=color: green)]]|| [[span(98, style=color: green)]]|| [[span(226, style=color:red)]]||
|| Intel Xeon X5365 ||
|| Intel Xeon X5482 ||
|| Intel Xeon X5675 ||
|| Intel Core i5-2520M ||
|| Intel Core i5-2500K ||
|| Intel Xeon E5-2680 ||
|| Intel Xeon E5-2667 v2 ||

== Conclusions ==