From 3d6ffe76f8a505c2dff5d5c6146da3d63dad6e82 Mon Sep 17 00:00:00 2001 From: Vladimir Serbinenko Date: Wed, 5 Feb 2014 17:00:40 +0100 Subject: [PATCH] load_payload: Use 32-bit accesses to speed up decompression. Flash prefers 32-bit sequential access. On some platforms ROM is not cached due to i.a. MTRR shortage. Moreover ROM caching is not currently enabled by default. With this patch payload decompression is sped up by theoretical factor of 4. Test on X201, with caching disabled: Before: 90:load payload 4,470,841 (24,505) 99:selfboot jump 6,073,812 (1,602,971) After: 90:load payload 4,530,979 (17,728) 99:selfboot jump 5,103,408 (572,429) Change-Id: Id17e61316dbbf73f4a837bf173f88bf26c01c62b Signed-off-by: Vladimir Serbinenko Reviewed-on: http://review.coreboot.org/5144 Reviewed-by: Aaron Durbin Reviewed-by: Paul Menzel Tested-by: build bot (Jenkins) --- src/lib/cbfs_core.c | 6 ++++++ src/lib/lzmadecode.c | 11 ++++++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/src/lib/cbfs_core.c b/src/lib/cbfs_core.c index 839b994cf3..50c037e573 100644 --- a/src/lib/cbfs_core.c +++ b/src/lib/cbfs_core.c @@ -202,6 +202,12 @@ int cbfs_decompress(int algo, void *src, void *dst, int len) { switch (algo) { case CBFS_COMPRESS_NONE: + /* Reads need to be aligned at 4 bytes to avoid + poor flash performance. */ + while (len && ((u32)src & 3)) { + *(u8*)dst++ = *(u8*)src++; + len--; + } memmove(dst, src, len); return len; #ifdef CBFS_CORE_WITH_LZMA diff --git a/src/lib/lzmadecode.c b/src/lib/lzmadecode.c index 1cf647d27b..fb57f4fd4d 100644 --- a/src/lib/lzmadecode.c +++ b/src/lib/lzmadecode.c @@ -28,7 +28,10 @@ #define kBitModelTotal (1 << kNumBitModelTotalBits) #define kNumMoveBits 5 -#define RC_READ_BYTE (*Buffer++) +/* Use 32-bit reads whenever possible to avoid bad flash performance. */ +#define RC_READ_BYTE (look_ahead_ptr < 4 ? look_ahead.raw[look_ahead_ptr++] \ + : ((((UInt32) Buffer & 3) || ((SizeT) (BufferLim - Buffer) < 4)) ? (*Buffer++) \ + : ((look_ahead.dw = *(UInt32 *)Buffer), (Buffer += 4), (look_ahead_ptr = 1), look_ahead.raw[0]))) #define RC_INIT2 Code = 0; Range = 0xFFFFFFFF; \ { int i; for(i = 0; i < 5; i++) { RC_TEST; Code = (Code << 8) | RC_READ_BYTE; }} @@ -149,6 +152,12 @@ int LzmaDecode(CLzmaDecoderState *vs, int len = 0; const Byte *Buffer; const Byte *BufferLim; + int look_ahead_ptr = 4; + union + { + Byte raw[4]; + UInt32 dw; + } look_ahead; UInt32 Range; UInt32 Code;