Vladimir Serbinenko (phcoder@gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5144
-gerrit
commit 7ca750324cfeedaafc72e6bc21dc9aa4d0524982 Author: Vladimir Serbinenko phcoder@gmail.com Date: Wed Feb 5 17:00:40 2014 +0100
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 decompress 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 phcoder@gmail.com --- 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 839b994..50c037e 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 1cf647d..b27e811 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) || ((unsigned long long) (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;