tip-bot for Peter Zijlstra wrote:
Commit-ID: 9d91a6f7a489eb914c16b82d927f9d81d629c259 Gitweb: http://git.kernel.org/tip/9d91a6f7a489eb914c16b82d927f9d81d629c259 Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> AuthorDate: Thu, 18 Jun 2009 11:40:28 +0200 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Thu, 18 Jun 2009 14:46:11 +0200 perf_counter tools: Handle lost events Make use of the new ->data_tail mechanism to tell kernel-space about user-space draining the data stream. Emit lost events (and display them) if they happen.
[snip]
@@ -109,7 +120,7 @@ static void mmap_read(struct mmap_data *md)
* In either case, truncate and restart at head.
*/
diff = head - old;
- if (diff > md->mask / 2 || diff < 0) {
+ if (diff < 0) {
struct timeval iv;
unsigned long msecs;
[snip] Hi Peter,Very nice change. One thing missing though on the above is an update to the comment which precedes snippet, which currently reads:
/* * If we're further behind than half the buffer, there's a chance * the writer will bite our tail and mess up the samples under us. * * If we somehow ended up ahead of the head, we got messed up. * * In either case, truncate and restart at head. */ The "further behind than half the buffer" no longer pertains. Maybe: /* * If we've gotten behind, truncate and restart at head. */ Regards, - Corey Corey Ashford Software Engineer IBM Linux Technology Center, Linux Toolchain cjashfor@xxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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