Messages in this thread | | | Date | Mon, 20 May 2002 08:46:11 -0400 | Subject | Re: O(1) scheduler gives big boost to tbench 192 | From | rwhron@earthlin ... |
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> On Tue, May 07, 2002 at 04:39:34PM -0700, Robert Love wrote: > > It is just for pipes we previously used sync, no?
On Tue, 7 May 2002 16:48:57 -0700, Mike Kravetz wrote > That's the only thing I know of that used it.
> I'd really like to know if there are any real workloads that > benefited from this feature, rather than just some benchmark. > I can do some research, but was hoping someone on this list > might remember. If there is a valid workload, I'll propose > a patch.
On Mon, 13 May 2002 02:06:31 +0200, J.A. Magallon wrote: > - Re-introduction of wake_up_sync to make pipes run fast again. No idea > about this is useful or not, that is the point, to test it
2.4.19-pre8-jam2 showed slightly better performance on the quad Xeon for most benchmarks with 25-wake_up_sync backed out. However, it's not clear to me 25-wake_up_sync was proper patch to backout for this test, as there wasn't a dramatic change in Pipe latency or bandwidth without it.
There was a > 300% improvement lmbench Pipe bandwidth and latency comparing pre8-jam2 to pre7-jam6.
Average of 25 lmbench runs on jam2 kernels, 12 on the others: 2.4.19-pre8-jam2-nowuos (backed out 25-wake_up_sync patch)
*Local* Communication latencies in microseconds - smaller is better AF kernel Pipe UNIX ----------------------- ----- ----- 2.4.19-pre7-jam6 29.51 42.37 2.4.19-pre8 10.73 29.94 2.4.19-pre8-aa2 12.45 29.53 2.4.19-pre8-ac1 35.39 45.59 2.4.19-pre8-jam2 7.70 15.27 2.4.19-pre8-jam2-nowuos 7.74 14.93
*Local* Communication bandwidths in MB/s - bigger is better AF kernel Pipe UNIX ----------------------- ------ ------ 2.4.19-pre7-jam6 66.41 260.39 2.4.19-pre8 468.57 273.32 2.4.19-pre8-aa2 418.09 273.59 2.4.19-pre8-ac1 110.62 241.06 2.4.19-pre8-jam2 545.66 233.68 2.4.19-pre8-jam2-nowuos 544.57 246.53
The kernel build test, which applies patches through a pipe and compiles with -pipe didn't reflect an improvement.
kernel average min_time max_time runs notes 2.4.19-pre7-jam6 237.0 235 239 3 All successful 2.4.19-pre8 239.7 238 241 3 All successful 2.4.19-pre8-aa2 237.7 237 238 3 All successful 2.4.19-pre8-ac1 239.3 238 241 3 All successful 2.4.19-pre8-jam2 240.0 238 241 3 All successful 2.4.19-pre8-jam2-nowuos 238.7 236 241 3 All successful
I don't know how much of the kernel build test is dependant on pipe performance. There is probably a better "real world" measurement.
On a single processor box, there was an improvement on kernel build between pre7-jam6 and pre8-jam2. That was only on one sample though.
Xeon page: http://home.earthlink.net/~rwhron/kernel/bigbox.html
Latest on uniproc: http://home.earthlink.net/~rwhron/kernel/latest.html
-- Randy Hron
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