Well, the overhead is certainly FAAAAR more than what TJ would encounter with multiple threads instead of multiple instances of AB. I still don't understand TJ's statement a while back that he couldn't see enough improvement to justify his implementing it (at least that's what I thought he said).
d > -----Original Message----- > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of Fred > Sent: Wednesday, June 18, 2008 1:50 PM > To: [email protected] > Subject: [amibroker] Re: Multi Core Optimization, L2 Cache & > Optimization Run Times > > Overhead is not a constant ... It is a function of a variety of > things not all of which am I even aware of and some of which can be > fairly significant ... > > --- In [email protected], "Ton Sieverding" > <[EMAIL PROTECTED]> wrote: > > > > Of course not. You'll always keep the overhead as a constant. But > as a rule of thumb it works fine for me in situations where time is > the bottleneck ... > > > > Regards, Ton. > > > > ----- Original Message ----- > > From: Fred Tonetti > > To: [email protected] > > Sent: Wednesday, June 18, 2008 2:25 PM > > Subject: RE: [amibroker] Multi Core Optimization, L2 Cache & > Optimization Run Times > > > > > > > > The relationship isn't quite that clear . > > > > > > > > I'm still playing with this feature for IO but if you are using > AB's exhaustive search for a variety of things and have a multiple > CPU / Core machine try MCO on some of your optimization problems . > > > > > > > > > > -------------------------------------------------------------------- > ---------- > > > > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of Ton Sieverding > > Sent: Wednesday, June 18, 2008 4:29 AM > > To: [email protected] > > Subject: Re: [amibroker] Multi Core Optimization, L2 Cache & > Optimization Run Times > > > > > > > > Fred does this show me that 'doubling the cores equals halving > the time' -) > > > > > > > > Regards, Ton. > > > > > > > > ----- Original Message ----- > > > > From: Fred Tonetti > > > > To: [email protected] > > > > Sent: Wednesday, June 18, 2008 1:10 AM > > > > Subject: RE: [amibroker] Multi Core Optimization, L2 Cache & > Optimization Run Times > > > > > > > > Here are some results I got with my new toy . > > > > This is using a reasonably complex system on ~500 symbols over > 10 years i.e. ~2500 bars ... > > > > Cores Time Percent > > > > 1 > 218 > > > > 2 114 52.29% > > > > 3 79 36.24% > > > > 4 62 28.44% > > > > 5 52 23.85% > > > > 6 46 21.10% > > > > 7 41 18.81% > > > > 8 37 16.97% > > > > As expected the higher you go the more overhead there is . but > improvements like this are still well worth the effort . Especially > on a single box . > > > > > > -------------------------------------------------------------------- > -------- > > > > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of Steve Dugas > > Sent: Saturday, June 14, 2008 7:00 PM > > To: [email protected] > > Subject: Re: [amibroker] Multi Core Optimization, L2 Cache & > Optimization Run Times > > > > Very interesting Fred, thanks! This looks encouraging, at > least for us EOD guys. > > > > One thing I notice - at 32 tickers, it looks like the curve > has "recovered" to what you might expect to see even if there was no > dent at 16. And also, after 32 the curve seems to get a second wind, > i.e. it "inverts" and the time per symbol decreases *more* rapidly as > more tickers are added. What do you think might account for that? Is > it just due to the log nature of the chart? Thanks! > > > > Steve > > > > ----- Original Message ----- > > > > From: Fred Tonetti > > > > To: [email protected] > > > > Sent: Saturday, June 14, 2008 5:49 PM > > > > Subject: [amibroker] Multi Core Optimization, L2 Cache & > Optimization Run Times > > > > Given TJ's comments about: > > > > - The amount of memory utilized in processing > symbols of data > > > > - Whether or not this would fit in the L2 cache > > > > - The effect it would have on optimizations when it > didn't > > > > I finally got around to running a little benchmark for Multi > Core Optimization using the program I wrote and posted ( MCO ) which > I'll be posting a new version of shortly . > > > > These tests were run under the following conditions: > > > > - A less than state of the art laptop with > > > > o Core 2 Duo 1.86 Ghz processor > > > > o 2 MB of L2 Cache > > > > - Watch Lists of symbols each of which > > > > o Contains the next power of two number of symbols of > the previous i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256 > > > > o Contains Symbols containing ~5000 bars of data . > > > > Given the above: > > > > - Each symbol should require 160,000 bytes i.e. > ~5,000 bars * 32 bytes per bar > > > > - Loading more than 13 symbols should cause L2 cache > misses to occur > > > > Results: > > > > - See the attached data & chart > > > > There are several interesting things I find regarding the > results . > > > > - The "dent" in the curve looking left to right > occurs right where you'd think it would, between 8 symbols and 16 > symbols i.e. from the point at which all data can be loaded to and > accessed from the L2 cache to the point where it no longer can . > > > > - The "dent" occurs in the same place running either > one or two instances of AB > > > > - The "dent" while clearly visible is hardly > traumatic in terms of run times > > > > - The relationship of run times between running one > and two instances of AB is consistent at 40% savings in terms of run > times regardless of the number of symbols. > > > > - This is also in line when one looks at how much > CPU is utilized when running one instance of AB which on the test > machine is typically in the 54 - 60% range. > > > > I have a new toy that I'll be trying these benchmarks on > again shortly i.e. a dual core 2 duo quad 3.0 ghz . > > > > > > > > > > -------------------------------------------------------------------- > -------- > > > > I am using the free version of SPAMfighter for private users. > > It has removed 480 spam emails to date. > > Paying users do not have this message in their emails. > > Try SPAMfighter for free now! > > > > > > > > > > > > > > -------------------------------------------------------------------- > ---------- > > I am using the free version of SPAMfighter for private users. > > It has removed 480 spam emails to date. > > Paying users do not have this message in their emails. > > Try SPAMfighter for free now! > > > > > > ------------------------------------ > > Please note that this group is for discussion between users only. > > To get support from AmiBroker please send an e-mail directly to > SUPPORT {at} amibroker.com > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > http://www.amibroker.com/devlog/ > > For other support material please check also: > http://www.amibroker.com/support.html > Yahoo! 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