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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-05-20 16:46:39 +0200
committerIngo Molnar <mingo@elte.hu>2010-05-21 11:37:59 +0200
commit5d967a8be636a4f301a8daad642bd1007299d9ec (patch)
treea55fa9c068f4a25a0de62797994353a36e165ca5 /kernel
parentadb8e118f288dc4c569ac9a89010b81a4745fbf0 (diff)
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perf: Optimize perf_output_copy()
Reduce the clutter in perf_output_copy() by keeping an interator in perf_output_handle. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20100521090710.742809176@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_event.c54
1 files changed, 26 insertions, 28 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 1531e0b409a..b67549a0862 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -2961,39 +2961,30 @@ again:
void perf_output_copy(struct perf_output_handle *handle,
const void *buf, unsigned int len)
{
- unsigned int pages_mask;
- unsigned long offset;
- unsigned int size;
- void **pages;
-
- offset = handle->offset;
- pages_mask = handle->data->nr_pages - 1;
- pages = handle->data->data_pages;
-
- do {
- unsigned long page_offset;
- unsigned long page_size;
- int nr;
-
- nr = (offset >> PAGE_SHIFT) & pages_mask;
- page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
- page_offset = offset & (page_size - 1);
- size = min_t(unsigned int, page_size - page_offset, len);
-
- memcpy(pages[nr] + page_offset, buf, size);
-
- len -= size;
- buf += size;
- offset += size;
- } while (len);
-
- handle->offset = offset;
+ handle->offset += len;
/*
* Check we didn't copy past our reservation window, taking the
* possible unsigned int wrap into account.
*/
- WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
+ if (WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0))
+ return;
+
+ do {
+ unsigned long size = min(handle->size, len);
+
+ memcpy(handle->addr, buf, size);
+
+ len -= size;
+ handle->addr += size;
+ handle->size -= size;
+ if (!handle->size) {
+ handle->page++;
+ handle->page &= handle->data->nr_pages - 1;
+ handle->addr = handle->data->data_pages[handle->page];
+ handle->size = PAGE_SIZE << handle->data->data_order;
+ }
+ } while (len);
}
int perf_output_begin(struct perf_output_handle *handle,
@@ -3059,6 +3050,13 @@ int perf_output_begin(struct perf_output_handle *handle,
if (head - local_read(&data->wakeup) > data->watermark)
local_add(data->watermark, &data->wakeup);
+ handle->page = handle->offset >> (PAGE_SHIFT + data->data_order);
+ handle->page &= data->nr_pages - 1;
+ handle->size = handle->offset & ((PAGE_SIZE << data->data_order) - 1);
+ handle->addr = data->data_pages[handle->page];
+ handle->addr += handle->size;
+ handle->size = (PAGE_SIZE << data->data_order) - handle->size;
+
if (have_lost) {
lost_event.header.type = PERF_RECORD_LOST;
lost_event.header.misc = 0;