rc4-586.pl: 50% improvement on Core2 and 80% on Westmere.

diff --git a/crypto/rc4/asm/rc4-586.pl b/crypto/rc4/asm/rc4-586.pl
index 38a44a70efc2412409c9c450c2448533510dafd1..116abb5b78e6cb2d5096386aa7900732af0eaabf 100644 (file)
--- a/crypto/rc4/asm/rc4-586.pl
+++ b/crypto/rc4/asm/rc4-586.pl
@@ -28,6 +28,31 @@
 #
 #                                      <appro@fy.chalmers.se>
 
+# May 2011
+#
+# Optimize for Core2 and Westmere [and Opteron]. Current performance
+# in cycles per processed byte (less is better) is:
+#
+# Pentium      10.2                    # original numbers
+# Pentium III  7.8(*)
+# Intel P4     7.5
+#
+# Opteron      6.4/+14%                # new MMX numbers
+# Core2                5.8/+50%(**)
+# Westmere     5.5/+80%(**)
+# Sandy Bridge 5.4/0%
+#
+# (*)  PIII can actually deliver 6.6 cycles per byte with MMX code,
+#      but this specific code performs poorly on Core2. While below
+#      MMX code delivering 5.8 on Core2 performs at 8.0 on PIII:-(
+#      As PIII is not a "hot" CPU [anymore], I chose not to introduce
+#      PIII-specific code path, which is why MMX code path is quarded
+#      by SSE2 bit (see below), not MMX.
+# (**) Performance vs. block size on Core2 and Westmere had a maximum
+#      at ... 64 bytes block size. And it was quite a maximum, 40-60%
+#      in comparison to largest 8KB block size. Above improvement
+#      coefficients are for the largest block size.
+
 $0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
 push(@INC,"${dir}","${dir}../../perlasm");
 require "x86asm.pl";
@@ -62,6 +87,60 @@ sub RC4_loop {
        &$func  ($out,&DWP(0,$dat,$ty,4));
 }
 
+if ($alt=0) {
+  # works ~5% faster on Atom and ~20% slower on Core2
+  my @XX=($xx,$out);
+  $RC4_loop_mmx = sub {
+    my $i=shift;
+
+       &add    ($yy,$tx);
+       &movz   ($yy,&LB($yy));
+       &lea    (@XX[1],&DWP(1,@XX[0]));
+       &psllq  ("mm1",8*(($i-1)&7))                    if (abs($i)!=1);
+       &and    (@XX[1],0xff);
+       &mov    ($ty,&DWP(0,$dat,$yy,4));
+       &mov    (&DWP(0,$dat,$yy,4),$tx);
+       &mov    (&DWP(0,$dat,$XX[0],4),$ty);
+       &add    ($ty,$tx);
+       &movd   (@XX[0],"mm7")                          if ($i==0);
+       &movz   ($ty,&LB($ty));
+       &mov    ($tx,&DWP(0,$dat,@XX[1],4));
+       &pxor   ("mm2",$i==1?"mm0":"mm1")               if ($i>=0);
+       &movq   ("mm0",&QWP(0,$inp))                    if ($i<=0);
+       &movq   (&QWP(-8,(@XX[0],$inp)),"mm2")          if ($i==0);
+       &movd   ($i>0?"mm1":"mm2",&DWP(0,$dat,$ty,4));
+
+       push    (@XX,shift(@XX))                        if ($i>=0);
+  }
+} else {
+  $RC4_loop_mmx = sub {
+    my $i=shift;
+
+       &add    ($yy,$tx);
+       &movz   ($yy,&LB($yy));                         # (*)
+       &psllq  ("mm1",8*(($i-1)&7))                    if (abs($i)!=1);
+       &mov    ($ty,&DWP(0,$dat,$yy,4));
+       &mov    (&DWP(0,$dat,$yy,4),$tx);
+       &mov    (&DWP(0,$dat,$xx,4),$ty);
+       &inc    ($xx);
+       &add    ($ty,$tx);
+       &movz   ($xx,&LB($xx));                         # (*)
+       &movz   ($ty,&LB($ty));                         # (*)
+       &pxor   ("mm2",$i==1?"mm0":"mm1")               if ($i>=0);
+       &movq   ("mm0",&QWP(0,$inp))                    if ($i<=0);
+       &movq   (&QWP(-8,($out,$inp)),"mm2")            if ($i==0);
+       &mov    ($tx,&DWP(0,$dat,$xx,4));
+       &movd   ($i>0?"mm1":"mm2",&DWP(0,$dat,$ty,4));
+
+       # (*)   This is the key to Core2 and Westmere performance.
+       #       Whithout movz out-of-order execution logic confuses
+       #       itself and fails to reorder loads and stores. Problem
+       #       appears to be fixed in Sandy Bridge...
+  }
+}
+
+&external_label("OPENSSL_ia32cap_P");
+
 # void RC4(RC4_KEY *key,size_t len,const unsigned char *inp,unsigned char *out);
 &function_begin("RC4");
        &mov    ($dat,&wparam(0));      # load key schedule pointer
@@ -94,11 +173,48 @@ sub RC4_loop {
        &and    ($ty,-4);               # how many 4-byte chunks?
        &jz     (&label("loop1"));
 
+       &test   ($ty,-8);
+       &mov    (&wparam(3),$out);      # $out as accumulator in these loops
+       &jz     (&label("go4loop4"));
+
+       &picmeup($out,"OPENSSL_ia32cap_P");
+       &bt     (&DWP(0,$out),26);      # check SSE2 bit [could have been MMX]
+       &jnc    (&label("go4loop4"));
+
+       &mov    ($out,&wparam(3))       if (!$alt);
+       &movd   ("mm7",&wparam(3))      if ($alt);
+       &and    ($ty,-8);
+       &lea    ($ty,&DWP(-8,$inp,$ty));
+       &mov    (&wparam(2),$ty);
+
+       &mov    (&DWP(-4,$dat),$ty);    # save input+(len/8)*8-8
+
+       &$RC4_loop_mmx(-1);
+       &jmp(&label("loop_mmx_enter"));
+
+       &set_label("loop_mmx",16);
+               &$RC4_loop_mmx(0);
+       &set_label("loop_mmx_enter");
+               for     ($i=1;$i<8;$i++) { &$RC4_loop_mmx($i); }
+               &cmp    ($inp,&DWP(-4,$dat));
+               &lea    ($inp,&DWP(8,$inp));
+       &jb     (&label("loop_mmx"));
+
+       &movd   ($out,"mm7")            if ($alt);
+       &psllq  ("mm1",56);
+       &pxor   ("mm2","mm1");
+       &movq   (&QWP(-8,$out,$inp),"mm2");
+       &emms   ();
+
+       &cmp    ($inp,&wparam(1));      # compare to input+len
+       &je     (&label("done"));
+       &jmp    (&label("loop1"));
+
+&set_label("go4loop4",16);
        &lea    ($ty,&DWP(-4,$inp,$ty));
        &mov    (&wparam(2),$ty);       # save input+(len/4)*4-4
-       &mov    (&wparam(3),$out);      # $out as accumulator in this loop
 
-       &set_label("loop4",16);
+       &set_label("loop4");
                for ($i=0;$i<4;$i++) { RC4_loop($i); }
                &ror    ($out,8);
                &xor    ($out,&DWP(0,$inp));
@@ -164,8 +280,6 @@ $idi="ebp";
 $ido="ecx";
 $idx="edx";
 
-&external_label("OPENSSL_ia32cap_P");
-
 # void RC4_set_key(RC4_KEY *key,int len,const unsigned char *data);
 &function_begin("RC4_set_key");
        &mov    ($out,&wparam(0));              # load key
@@ -254,14 +368,21 @@ $idx="edx";
        &blindpop("eax");
        &lea    ("eax",&DWP(&label("opts")."-".&label("pic_point"),"eax"));
        &picmeup("edx","OPENSSL_ia32cap_P");
-       &bt     (&DWP(0,"edx"),20);
-       &jnc    (&label("skip"));
-         &add  ("eax",12);
-       &set_label("skip");
+       &mov    ("edx",&DWP(0,"edx"));
+       &bt     ("edx",20);
+       &jc     (&label("1xchar"));
+       &bt     ("edx",26);
+       &jnc    (&label("ret"));
+       &add    ("eax",25);
+       &ret    ();
+&set_label("1xchar");
+       &add    ("eax",12);
+&set_label("ret");
        &ret    ();
 &set_label("opts",64);
 &asciz ("rc4(4x,int)");
 &asciz ("rc4(1x,char)");
+&asciz ("rc4(8x,mmx)");
 &asciz ("RC4 for x86, CRYPTOGAMS by <appro\@openssl.org>");
 &align (64);
 &function_end_B("RC4_options");