Re: [PATCH RFC V10 0/18] Paravirtualized ticket spinlocks

From: Raghavendra K T
Date: Wed Jun 26 2013 - 04:29:58 EST


On 06/24/2013 06:47 PM, Andrew Jones wrote:
On Mon, Jun 24, 2013 at 06:10:14PM +0530, Raghavendra K T wrote:

Results:
=======
base = 3.10-rc2 kernel
patched = base + this series

The test was on 32 core (model: Intel(R) Xeon(R) CPU X7560) HT disabled
with 32 KVM guest vcpu 8GB RAM.

Have you ever tried to get results with HT enabled?


+-----------+-----------+-----------+------------+-----------+
ebizzy (records/sec) higher is better
+-----------+-----------+-----------+------------+-----------+
base stdev patched stdev %improvement
+-----------+-----------+-----------+------------+-----------+
1x 5574.9000 237.4997 5618.0000 94.0366 0.77311
2x 2741.5000 561.3090 3332.0000 102.4738 21.53930
3x 2146.2500 216.7718 2302.3333 76.3870 7.27237
4x 1663.0000 141.9235 1753.7500 83.5220 5.45701
+-----------+-----------+-----------+------------+-----------+

This looks good. Are your ebizzy results consistent run to run
though?

+-----------+-----------+-----------+------------+-----------+
dbench (Throughput) higher is better
+-----------+-----------+-----------+------------+-----------+
base stdev patched stdev %improvement
+-----------+-----------+-----------+------------+-----------+
1x 14111.5600 754.4525 14645.9900 114.3087 3.78718
2x 2481.6270 71.2665 2667.1280 73.8193 7.47498
3x 1510.2483 31.8634 1503.8792 36.0777 -0.42173
4x 1029.4875 16.9166 1039.7069 43.8840 0.99267
+-----------+-----------+-----------+------------+-----------+

Hmm, I wonder what 2.5x looks like. Also, the 3% improvement with
no overcommit is interesting. What's happening there? It makes
me wonder what < 1x looks like.


Hi Andrew,

I tried 2.5x case sort where I used 3 guests with 27 vcpu each on 32
core (HT disabled machine) and here is the output. almost no gain there.

throughput avg stdev
base: 1768.7458 MB/sec 54.044221
patched: 1772.5617 MB/sec 41.227689
gain %0.226

I am yet to try HT enabled cases that would give 0.5x to 2x performance
results.

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