This is the mail archive of the
cygwin-patches
mailing list for the Cygwin project.
[PATCH] fhandler_proc/cpuinfo: support fast short REP MOVSB
- From: Brian Inglis <Brian dot Inglis at SystematicSW dot ab dot ca>
- To: Cygwin Patches <cygwin-patches at cygwin dot com>
- Cc: Brian Inglis <Brian dot Inglis at SystematicSW dot ab dot ca>
- Date: Fri, 21 Feb 2020 14:28:08 -0700
- Subject: [PATCH] fhandler_proc/cpuinfo: support fast short REP MOVSB
Added in Linux 5.6:
Check FSRM and use REP MOVSB for short copies on systems that have it.
>From the Intel Optimization Reference Manual:
3.7.6.1 Fast Short REP MOVSB
Beginning with processors based on Ice Lake Client microarchitecture,
REP MOVSB performance is enhanced with string lengths up to 128 bytes.
Support for fast-short REP MOVSB is indicated by the CPUID feature flag:
CPUID [EAX=7H, ECX=0H).EDX.FAST_SHORT_REP_MOVSB[bit 4] = 1.
There is no change in the REP STOS performance.
---
winsup/cygwin/fhandler_proc.cc | 1 +
1 file changed, 1 insertion(+)
diff --git a/winsup/cygwin/fhandler_proc.cc b/winsup/cygwin/fhandler_proc.cc
index 78a69703d..030ade68a 100644
--- a/winsup/cygwin/fhandler_proc.cc
+++ b/winsup/cygwin/fhandler_proc.cc
@@ -1346,6 +1346,7 @@ format_proc_cpuinfo (void *, char *&destbuf)
ftcprint (features1, 2, "avx512_4vnniw"); /* vec dot prod dw */
ftcprint (features1, 3, "avx512_4fmaps"); /* vec 4 FMA single */
+ ftcprint (features1, 4, "fsrm"); /* fast short REP MOVSB */
ftcprint (features1, 8, "avx512_vp2intersect"); /* vec intcpt d/q */
ftcprint (features1, 10, "md_clear"); /* verw clear buf */
ftcprint (features1, 18, "pconfig"); /* platform config */
--
2.21.0