On 05/15/15 03:34 PM, Peter Harris wrote:
On 2015-05-15 01:48, Alan Coopersmith wrote:
Speaking of which, something I've wondered about for a while, but never
had time to test, is if telling the server to optimize for valid requests
would make a difference, such as:
#define REQUEST_AT_LEAST_SIZE(req) \
- if ((sizeof(req) >> 2) > client->req_len )\
+ if (_X_UNLIKELY((sizeof(req) >> 2) > client->req_len )) \
return(BadLength)
If anyone wants to try it out and report back, please do so!
Slightly less than 1% improvement on x11perf -noop. Stable over multiple
runs:
before after Operation
---------- ----------------- --------------------
13800000.0 13900000.0 (1.01) X protocol NoOperation
I didn't try the full patch or a full x11perf run, but it seems unlikely
that it would be significant on a real load.
Thanks - since even a noop goes through a sizable stack, it's not that tight
of a loop going through this code, and I wouldn't be surprised if optimizers
already assume early return paths like that are uncommon error cases.
--
-Alan Coopersmith- [email protected]
Oracle Solaris Engineering - http://blogs.oracle.com/alanc
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