| Message ID | 1363881457-14814-6-git-send-email-pl@kamp.de |
|---|---|
| State | New |
| Headers | show |
On 03/21/2013 09:57 AM, Peter Lieven wrote: > virtually all dup pages are zero pages. remove > the special is_dup_page() function and use the > optimized buffer_find_nonzero_offset() function > instead. > > here buffer_find_nonzero_offset() is used directly > to avoid the unnecssary additional checks in > buffer_is_zero(). > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > - return 1; > + return > + buffer_find_nonzero_offset(p, TARGET_PAGE_SIZE) == TARGET_PAGE_SIZE; Unusual layout. I would have written: return buffer_find_nonzero_offset(p, TARGET_PAGE_SIZE) == TARGET_PAGE_SIZE; > /* struct contains XBZRLE cache and a static page > @@ -443,7 +434,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage) > > /* In doubt sent page as normal */ > bytes_sent = -1; > - if (is_dup_page(p)) { > + if (is_zero_page(p)) { > acct_info.dup_pages++; > bytes_sent = save_block_hdr(f, block, offset, cont, > RAM_SAVE_FLAG_COMPRESS); I would move the change for qemu_put_byte(f, 0) out of patch 7 into this patch, since this is the first point where you know the byte to send is 0.
diff --git a/arch_init.c b/arch_init.c index 1b71912..6806727 100644 --- a/arch_init.c +++ b/arch_init.c @@ -144,19 +144,10 @@ int qemu_read_default_config_files(bool userconfig) return 0; } -static int is_dup_page(uint8_t *page) +static inline bool is_zero_page(uint8_t *p) { - VECTYPE *p = (VECTYPE *)page; - VECTYPE val = SPLAT(page); - int i; - - for (i = 0; i < TARGET_PAGE_SIZE / sizeof(VECTYPE); i++) { - if (!ALL_EQ(val, p[i])) { - return 0; - } - } - - return 1; + return + buffer_find_nonzero_offset(p, TARGET_PAGE_SIZE) == TARGET_PAGE_SIZE; } /* struct contains XBZRLE cache and a static page @@ -443,7 +434,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage) /* In doubt sent page as normal */ bytes_sent = -1; - if (is_dup_page(p)) { + if (is_zero_page(p)) { acct_info.dup_pages++; bytes_sent = save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_COMPRESS);
virtually all dup pages are zero pages. remove the special is_dup_page() function and use the optimized buffer_find_nonzero_offset() function instead. here buffer_find_nonzero_offset() is used directly to avoid the unnecssary additional checks in buffer_is_zero(). Signed-off-by: Peter Lieven <pl@kamp.de> --- arch_init.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-)