Re: [PATCH] Add 2-pass mode to gtags

[Hideki IWAMOTO]

Hi.
> What is the purpose of this patch?
> Is it achieved?

The purpose of this patch is to improve the performance of 2-pass mode when 
btree cache is small. 
Because the effect is too small, I withdraw the proposal of this change. 

======== patched version ========
$ foreach cpumask ( 1 3 )
foreach? foreach label ( default 2pass )
foreach? echo ==== cpumask:$cpumask label:$label ====
foreach? foreach cachesize ( 8388608 16777216 33554432 67108864 )
foreach? rm -fr linux-2.6.31; tar xfj ~/download/linux/linux-2.6.31.tar.bz2; 
sync
foreach? (cd linux-2.6.31; time taskset $cpumask env GTAGSLABEL=$label 
GTAGSCACHE=$cachesize gtags)
foreach? end
foreach? end
foreach? end
==== cpumask:1 label:default ====
118.375u 22.325s 3:08.73 74.5%  0+0k 0+0io 0pf+0w
118.599u 19.161s 2:55.48 78.4%  0+0k 0+0io 0pf+0w
119.483u 16.981s 2:28.53 91.8%  0+0k 0+0io 0pf+0w
120.067u 15.352s 2:26.71 92.2%  0+0k 0+0io 0pf+0w
==== cpumask:1 label:2pass ====
91.801u 19.181s 3:31.89 52.3%   0+0k 0+0io 0pf+0w
93.373u 16.573s 2:59.26 61.3%   0+0k 0+0io 0pf+0w
93.773u 13.800s 2:08.25 83.8%   0+0k 0+0io 0pf+0w
94.013u 12.024s 1:57.77 90.0%   0+0k 0+0io 0pf+0w
==== cpumask:3 label:default ====
115.659u 22.733s 2:43.76 84.5%  0+0k 0+0io 0pf+0w
116.391u 18.085s 2:27.60 91.1%  0+0k 0+0io 0pf+0w
116.979u 16.765s 2:14.85 99.1%  0+0k 0+0io 0pf+0w
118.147u 15.668s 2:12.72 100.8% 0+0k 0+0io 0pf+0w
==== cpumask:3 label:2pass ====
89.073u 17.949s 3:00.21 59.3%   0+0k 0+0io 0pf+0w
90.521u 14.816s 2:19.45 75.5%   0+0k 0+0io 0pf+0w
89.993u 12.908s 1:41.30 101.5%  0+0k 0+0io 0pf+0w
90.617u 11.472s 1:27.85 116.1%  0+0k 0+0io 0pf+0w

======= current CVS version ======
> $ foreach cpumask ( 1 3 )
> foreach? foreach label ( default 2pass )
> foreach? echo ==== cpumask:$cpumask label:$label ====
> foreach? foreach cachesize ( 8388608 16777216 33554432 67108864 )
> foreach? rm -fr linux-2.6.31; tar xfj ~/download/linux/linux-2.6.31.tar.bz2; 
> sync
> foreach? (cd linux-2.6.31; time taskset $cpumask env GTAGSLABEL=$label 
> GTAGSCACHE=$cachesize gtags)
> foreach? end
> foreach? end
> foreach? end
> ==== cpumask:1 label:default ====
> 114.267u 24.085s 3:09.48 73.0%  0+0k 0+0io 1pf+0w
> 115.367u 20.521s 2:55.73 77.3%  0+0k 0+0io 0pf+0w
> 116.227u 18.081s 2:32.98 87.7%  0+0k 0+0io 0pf+0w
> 116.671u 16.093s 2:24.36 91.9%  0+0k 0+0io 0pf+0w
> ==== cpumask:1 label:2pass ====
> 91.353u 19.205s 3:48.79 48.3%   0+0k 0+0io 0pf+0w
> 92.317u 16.501s 3:05.40 58.6%   0+0k 0+0io 0pf+0w
> 92.797u 13.580s 2:08.52 82.7%   0+0k 0+0io 0pf+0w
> 93.929u 11.080s 1:56.03 90.4%   0+0k 0+0io 0pf+0w
> ==== cpumask:3 label:default ====
> 112.507u 23.593s 2:48.80 80.6%  0+0k 0+0io 1pf+0w
> 112.991u 18.965s 2:30.06 87.9%  0+0k 0+0io 0pf+0w
> 113.591u 17.305s 2:13.30 98.1%  0+0k 0+0io 0pf+0w
> 114.831u 16.113s 2:11.92 99.2%  0+0k 0+0io 0pf+0w
> ==== cpumask:3 label:2pass ====
> 88.773u 18.929s 3:17.01 54.6%   0+0k 0+0io 0pf+0w
> 90.085u 15.108s 2:35.38 67.6%   0+0k 0+0io 0pf+0w
> 90.877u 12.204s 1:44.62 98.5%   0+0k 0+0io 0pf+0w
> 91.217u 10.540s 1:29.74 113.3%  0+0k 0+0io 0pf+0w

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Hideki IWAMOTO  address@hidden