From 86f9ce97bc4dd8dd14757157ae944c2c678d62a9 Mon Sep 17 00:00:00 2001 From: Brian Inglis 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 */