143385 2015-04-03 14:14:03 -0700 Add Options::jitPolicyScale() as a single knob to make all compilations happen sooner 2015-04-03 15:53:28 -0700 1 1 1 Unclassified WebKit JavaScriptCore 528+ (Nightly build) Unspecified Unspecified RESOLVED FIXED P2 Normal --- 1 mark.lam mark.lam benjamin fpizlo ggaren mhahnenb mmirman msaboff oliver oldest_to_newest 1082671 0 mark.lam 2015-04-03 14:14:03 -0700 For debugging purposes, sometimes, we want to be able to make compilation happen sooner to see if we can accelerate the manifestation of certain events / bugs. Currently, in order to achieve this, we'll have to tweak multiple JIT thresholds which make up the compilation policy. Let's add a single knob that can tune all the thresholds up / down proportionately so that we easily can tweak how soon compilation occurs. 1082672 1 250096 mark.lam 2015-04-03 14:19:14 -0700 Created attachment 250096 the patch. 1082682 2 250096 msaboff 2015-04-03 14:44:00 -0700 Comment on attachment 250096 the patch. I don't like this and find it not too helpful. To come up with a scale, I need to calculate the ration to match the value I want to change. Right now, I use the values that run-jsc-stress-test sets. In fact I typically copy them from the output of a failing tests. The ratio of the various values set in run-jsc-stress-tests wouldn't work with the same ratio. For example, thresholdForJITAfterWarmUp is 500 and thresholdForJITSoon is 100 by default. The "eager" tests set these both to 10, which is a different ratio for each of these parameters. 1082692 3 mark.lam 2015-04-03 15:04:31 -0700 (In reply to comment #2) > Comment on attachment 250096 [details] > the patch. > > I don't like this and find it not too helpful. To come up with a scale, I > need to calculate the ration to match the value I want to change. Right > now, I use the values that run-jsc-stress-test sets. In fact I typically > copy them from the output of a failing tests. The ratio of the various > values set in run-jsc-stress-tests wouldn't work with the same ratio. For > example, thresholdForJITAfterWarmUp is 500 and thresholdForJITSoon is 100 by > default. The "eager" tests set these both to 10, which is a different ratio > for each of these parameters. To each his own. In my case, I'm looking to reproduce issues that occur naturally in the wild, but are normally rare. As such, I would want the policy to reflect the ratios that are used in real world usage, except that I want it accelerated. This knob gives me a convenient way to tweak that acceleration and re-test my repro case. The alternative approach you prescribed has 3 disadvantages for my use case: 1. Those jsc stress threshold values don't reflect the ratios that trigger compilation in the real world. Hence, it can change the order in which functions are compiled, and is therefore, not necessarily better for reproduction of real world bugs. Granted, scaling down the thresholds proportionately is not exactly perfect either (especially) when it reaches the very small value, but it is better at preserving the natural order of compilations. 2. It's a hassle to have to get a fresh run of the jsc stress tests and then hunt down specific tests to copy their policy values out of the generated scripts. 3. It is also a hassle to have to set and tweak multiple option variables instead of one, especially when I do want to preserve the threshold ratios used in the real world. 1082703 4 250096 ggaren 2015-04-03 15:44:39 -0700 Comment on attachment 250096 the patch. r=me 1082707 5 mark.lam 2015-04-03 15:53:28 -0700 Thanks. Landed in r182337: <http://trac.webkit.org/r182337>. 250096 2015-04-03 14:19:14 -0700 2015-04-03 15:44:39 -0700 the patch. bug-143385.patch text/plain 3958 mark.lam SW5kZXg6IFNvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cKPT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PQotLS0gU291 cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwkocmV2aXNpb24gMTgyMzMxKQorKysgU291cmNl L0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwkod29ya2luZyBjb3B5KQpAQCAtMSwzICsxLDIyIEBA CisyMDE1LTA0LTAzICBNYXJrIExhbSAgPG1hcmsubGFtQGFwcGxlLmNvbT4KKworICAgICAgICBB ZGQgT3B0aW9uczo6aml0UG9saWN5U2NhbGUoKSBhcyBhIHNpbmdsZSBrbm9iIHRvIG1ha2UgYWxs IGNvbXBpbGF0aW9ucyBoYXBwZW4gc29vbmVyLgorICAgICAgICA8aHR0cHM6Ly93ZWJraXQub3Jn L2IvMTQzMzg1PgorCisgICAgICAgIFJldmlld2VkIGJ5IE5PQk9EWSAoT09QUyEpLgorCisgICAg ICAgIEZvciBkZWJ1Z2dpbmcgcHVycG9zZXMsIHNvbWV0aW1lcywgd2Ugd2FudCB0byBiZSBhYmxl IHRvIG1ha2UgY29tcGlsYXRpb24gaGFwcGVuCisgICAgICAgIHNvb25lciB0byBzZWUgaWYgd2Ug 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