Messages in this thread |  | | From | kumon@flab ... | Date | Tue, 7 Nov 2000 12:15:16 +0900 | Subject | locks.c: removal of semaphores |
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Andrew, I got 5250 Req/s with your locks-sem.patch on normal Apache. It is good performance on normal Apache.
Andrew Morton writes: > Kouichi, could you please test the performance of this on > your 8-way with Apache+fcntl serialisation? (the normal > Apache). Please use 2.4.0-test10-pre5, not 2.4.0-test10. > Something has gone funny with test10 and I'm getting much > lower rates.
Followings are the recent data with/without serialization.
w/ serialize w/o serialize 240t10pre5 2237 5358 240t10pre5+P2 5253 5355** 240t10pre5+P3 --- NG 240t10pre5+locksem 5250 --- **: once we found deadlock NG: cannot complete measurement --: we've not measured.
Normal apache on various kernel setting as follows:
> test8 5287 <-- best performance > test10-pre5+P2 5258 > 240t10pre5+locksem 5250 > test9+P2 5243 > test9+mypatch 5192 <-- a little bit worse > test10-pre5+P1 5187 > test1 3702 <-- no good scalability > test10-pre5 2255 <-- negative scalability > test9 2193
We also did durability test of 2.4.0-test10-pre5. Unfortunately enough, we didn't successfully complete the test of Apache w/o serialization (-DSINGLE_LISTEN_UNSERIALIZED_ACCEPT), it couldn't continue to run for a night. The kernel got complete deadlock.
The message is: "Unable to handle kernel NULL pointer dereference NMI watchdog detected LOCKUP on CPU1."
Yes, obviously it's not Andrew's problem, that is genuine test10-pre5.
Hidden bugs are awakened by removing serialization.
If the bug is same as what I observed, It is NULL pointer dereference on run-queue list. -- Computer Systems Laboratory, Fujitsu Labs. kumon@flab.fujitsu.co.jp - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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