From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B3A8C05027 for ; Mon, 6 Feb 2023 09:28:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229711AbjBFJ2R (ORCPT ); Mon, 6 Feb 2023 04:28:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229542AbjBFJ2Q (ORCPT ); Mon, 6 Feb 2023 04:28:16 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D92071BD2; Mon, 6 Feb 2023 01:28:14 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BF661113E; Mon, 6 Feb 2023 01:28:56 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.91.13]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0B6293F71E; Mon, 6 Feb 2023 01:28:11 -0800 (PST) Date: Mon, 6 Feb 2023 09:28:09 +0000 From: Mark Rutland To: "Wangshaobo (bobo)" Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, ndesaulniers@google.com, ojeda@kernel.org, peterz@infradead.org, rafael.j.wysocki@intel.com, revest@chromium.org, robert.moore@intel.com, rostedt@goodmis.org, will@kernel.org, "liwei (GF)" Subject: Re: [PATCH v3 1/8] ftrace: Add DYNAMIC_FTRACE_WITH_CALL_OPS Message-ID: References: <20230123134603.1064407-1-mark.rutland@arm.com> <20230123134603.1064407-2-mark.rutland@arm.com> <60ec7607-7c5c-1a6e-18c9-8025cb2f289f@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <60ec7607-7c5c-1a6e-18c9-8025cb2f289f@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tue, Jan 31, 2023 at 09:25:51AM +0800, Wangshaobo (bobo) wrote: > 在 2023/1/30 18:25, Mark Rutland 写道: > > On Sat, Jan 28, 2023 at 04:46:48PM +0800, Wangshaobo (bobo) wrote: > > > 锟斤拷 2023/1/23 21:45, Mark Rutland 写锟斤拷: > > > > +config DYNAMIC_FTRACE_WITH_CALL_OPS > > > > + def_bool y > > > > + depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS > > > > + > > > Hi Mark, > > > > Hi, > > > > > I have test your patches and it looks fine with my sample module, > > > > Thanks for testing! > > > > > but here setting DYNAMIC_FTRACE_WITH_CALL_OPS to y immutably may increase the > > > .text section size by 5% or more, how about making this to optional^^ > > > > We could consider making this optional. I had not made this optional so far as > > in the future I'd like to make this the only implementation of ftrace on arm64 > > (once we can drop the old mcount version, and once we've sorted out the > > incompatibility with CFI). In the mean time, it probably makes sense to have > > the option at least to enable testing of each of the two forms. > > > > Is your concern that the overall kernel image size is larger, or do you care > > specifically about the size of the .text section for some reason? > > > > Thanks, > > Mark > Embedded devices may pay more attention to Image size, and which may also > indirectly affects performance, for more reason, I appreciate those concerns, however: a) For the Image size, the mcount_loc table and associated relocations already imposes a much greater penalty. So I'd expect that where the size truly matters, ftrace would be completely disabled anyway. I'm currently looking at shrinking the mcount_loc table (and removing the need for relocationgs), which should save much more space. b) For performance, without data this is supposition. Everything so far indicates that there is not a measureable performance difference, and from other threads it's possible that the increased function alignment *aids* performance. If you have data to the contrary, I'm happy to investigate. > I think making sense to have the option for testing is more important. As above, I'm happy to add an option for functional testing of the ftrace implementation, but I don't think that it's a good idea to use that as a size or performance tweak. Thanks, Mark. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BAAE2C05027 for ; Mon, 6 Feb 2023 09:29:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=FGqJerzmrPUto4rhTkErpGz/4M3wnadmOKktTADvBBA=; b=YLix278N0Ylcx0 Hz5MSAQsOC3toLdMSX18vgmaf0c1oJFwUipdrK29LWdokVnMiAg17nyYmyNhmPiVbdERp3njCwM1H 8z9R0KbqyKdvONMQgeiZU8YUh6CuxWlhcf83Ggo+NaTBlHeAImlUGszHRpVwQCN/S1fscLwomXVGT eseEh+gBtUFk37ixV5PXW7jSgv+JMQW+mggLfzmzu5Q7AEgKM6sonMPaY+dy29F2lB1Y4mCxMy083 hM4dnnI2lcUMyeccrUOFv5rjyy1PGK+iIxGKaGeR7zmSWY6/tguTVucP1adaqWQIx1bhB161BVfEy VLYeLvhxt1seo8mLfJgw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pOxnS-007sJY-Cs; Mon, 06 Feb 2023 09:28:22 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pOxnM-007sF8-05 for linux-arm-kernel@lists.infradead.org; Mon, 06 Feb 2023 09:28:18 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BF661113E; Mon, 6 Feb 2023 01:28:56 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.91.13]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0B6293F71E; Mon, 6 Feb 2023 01:28:11 -0800 (PST) Date: Mon, 6 Feb 2023 09:28:09 +0000 From: Mark Rutland To: "Wangshaobo (bobo)" Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, ndesaulniers@google.com, ojeda@kernel.org, peterz@infradead.org, rafael.j.wysocki@intel.com, revest@chromium.org, robert.moore@intel.com, rostedt@goodmis.org, will@kernel.org, "liwei (GF)" Subject: Re: [PATCH v3 1/8] ftrace: Add DYNAMIC_FTRACE_WITH_CALL_OPS Message-ID: References: <20230123134603.1064407-1-mark.rutland@arm.com> <20230123134603.1064407-2-mark.rutland@arm.com> <60ec7607-7c5c-1a6e-18c9-8025cb2f289f@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <60ec7607-7c5c-1a6e-18c9-8025cb2f289f@huawei.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230206_012816_112226_78A69271 X-CRM114-Status: GOOD ( 30.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gVHVlLCBKYW4gMzEsIDIwMjMgYXQgMDk6MjU6NTFBTSArMDgwMCwgV2FuZ3NoYW9ibyAoYm9i bykgd3JvdGU6Cj4g5ZyoIDIwMjMvMS8zMCAxODoyNSwgTWFyayBSdXRsYW5kIOWGmemBkzoKPiA+ IE9uIFNhdCwgSmFuIDI4LCAyMDIzIGF0IDA0OjQ2OjQ4UE0gKzA4MDAsIFdhbmdzaGFvYm8gKGJv Ym8pIHdyb3RlOgo+ID4gPiDplJ/mlqTmi7cgMjAyMy8xLzIzIDIxOjQ1LCBNYXJrIFJ1dGxhbmQg 5YaZ6ZSf5pak5ou3Ogo+ID4gPiA+ICtjb25maWcgRFlOQU1JQ19GVFJBQ0VfV0lUSF9DQUxMX09Q Uwo+ID4gPiA+ICsJZGVmX2Jvb2wgeQo+ID4gPiA+ICsJZGVwZW5kcyBvbiBIQVZFX0RZTkFNSUNf RlRSQUNFX1dJVEhfQ0FMTF9PUFMKPiA+ID4gPiArCj4gPiA+IEhpIE1hcmssCj4gPiAKPiA+IEhp LAo+ID4gCj4gPiA+IEkgaGF2ZSB0ZXN0IHlvdXIgcGF0Y2hlcyBhbmQgaXQgbG9va3MgZmluZSB3 aXRoIG15IHNhbXBsZSBtb2R1bGUsCj4gPiAKPiA+IFRoYW5rcyBmb3IgdGVzdGluZyEKPiA+IAo+ ID4gPiBidXQgaGVyZSBzZXR0aW5nIERZTkFNSUNfRlRSQUNFX1dJVEhfQ0FMTF9PUFMgdG8geSBp bW11dGFibHkgbWF5IGluY3JlYXNlIHRoZQo+ID4gPiAudGV4dCBzZWN0aW9uIHNpemUgYnkgNSUg b3IgbW9yZSwgaG93IGFib3V0IG1ha2luZyB0aGlzIHRvIG9wdGlvbmFsXl4KPiA+IAo+ID4gV2Ug Y291bGQgY29uc2lkZXIgbWFraW5nIHRoaXMgb3B0aW9uYWwuIEkgaGFkIG5vdCBtYWRlIHRoaXMg b3B0aW9uYWwgc28gZmFyIGFzCj4gPiBpbiB0aGUgZnV0dXJlIEknZCBsaWtlIHRvIG1ha2UgdGhp cyB0aGUgb25seSBpbXBsZW1lbnRhdGlvbiBvZiBmdHJhY2Ugb24gYXJtNjQKPiA+IChvbmNlIHdl IGNhbiBkcm9wIHRoZSBvbGQgbWNvdW50IHZlcnNpb24sIGFuZCBvbmNlIHdlJ3ZlIHNvcnRlZCBv dXQgdGhlCj4gPiBpbmNvbXBhdGliaWxpdHkgd2l0aCBDRkkpLiBJbiB0aGUgbWVhbiB0aW1lLCBp dCBwcm9iYWJseSBtYWtlcyBzZW5zZSB0byBoYXZlCj4gPiB0aGUgb3B0aW9uIGF0IGxlYXN0IHRv IGVuYWJsZSB0ZXN0aW5nIG9mIGVhY2ggb2YgdGhlIHR3byBmb3Jtcy4KPiA+IAo+ID4gSXMgeW91 ciBjb25jZXJuIHRoYXQgdGhlIG92ZXJhbGwga2VybmVsIGltYWdlIHNpemUgaXMgbGFyZ2VyLCBv ciBkbyB5b3UgY2FyZQo+ID4gc3BlY2lmaWNhbGx5IGFib3V0IHRoZSBzaXplIG9mIHRoZSAudGV4 dCBzZWN0aW9uIGZvciBzb21lIHJlYXNvbj8KPiA+IAo+ID4gVGhhbmtzLAo+ID4gTWFyawo+IEVt YmVkZGVkIGRldmljZXMgbWF5IHBheSBtb3JlIGF0dGVudGlvbiB0byBJbWFnZSBzaXplLCBhbmQg d2hpY2ggbWF5IGFsc28KPiBpbmRpcmVjdGx5IGFmZmVjdHMgcGVyZm9ybWFuY2UsIGZvciBtb3Jl IHJlYXNvbiwKCkkgYXBwcmVjaWF0ZSB0aG9zZSBjb25jZXJucywgaG93ZXZlcjoKCmEpIEZvciB0 aGUgSW1hZ2Ugc2l6ZSwgdGhlIG1jb3VudF9sb2MgdGFibGUgYW5kIGFzc29jaWF0ZWQgcmVsb2Nh dGlvbnMgYWxyZWFkeQogICBpbXBvc2VzIGEgbXVjaCBncmVhdGVyIHBlbmFsdHkuIFNvIEknZCBl eHBlY3QgdGhhdCB3aGVyZSB0aGUgc2l6ZSB0cnVseQogICBtYXR0ZXJzLCBmdHJhY2Ugd291bGQg YmUgY29tcGxldGVseSBkaXNhYmxlZCBhbnl3YXkuCgogICBJJ20gY3VycmVudGx5IGxvb2tpbmcg YXQgc2hyaW5raW5nIHRoZSBtY291bnRfbG9jIHRhYmxlIChhbmQgcmVtb3ZpbmcgdGhlCiAgIG5l ZWQgZm9yIHJlbG9jYXRpb25ncyksIHdoaWNoIHNob3VsZCBzYXZlIG11Y2ggbW9yZSBzcGFjZS4K CmIpIEZvciBwZXJmb3JtYW5jZSwgd2l0aG91dCBkYXRhIHRoaXMgaXMgc3VwcG9zaXRpb24uIEV2 ZXJ5dGhpbmcgc28gZmFyCiAgIGluZGljYXRlcyB0aGF0IHRoZXJlIGlzIG5vdCBhIG1lYXN1cmVh YmxlIHBlcmZvcm1hbmNlIGRpZmZlcmVuY2UsIGFuZCBmcm9tCiAgIG90aGVyIHRocmVhZHMgaXQn cyBwb3NzaWJsZSB0aGF0IHRoZSBpbmNyZWFzZWQgZnVuY3Rpb24gYWxpZ25tZW50ICphaWRzKgog ICBwZXJmb3JtYW5jZS4KCiAgIElmIHlvdSBoYXZlIGRhdGEgdG8gdGhlIGNvbnRyYXJ5LCBJJ20g aGFwcHkgdG8gaW52ZXN0aWdhdGUuCgo+IEkgdGhpbmsgbWFraW5nIHNlbnNlIHRvIGhhdmUgdGhl IG9wdGlvbiBmb3IgdGVzdGluZyBpcyBtb3JlIGltcG9ydGFudC4KCkFzIGFib3ZlLCBJJ20gaGFw cHkgdG8gYWRkIGFuIG9wdGlvbiBmb3IgZnVuY3Rpb25hbCB0ZXN0aW5nIG9mIHRoZSBmdHJhY2UK aW1wbGVtZW50YXRpb24sIGJ1dCBJIGRvbid0IHRoaW5rIHRoYXQgaXQncyBhIGdvb2QgaWRlYSB0 byB1c2UgdGhhdCBhcyBhIHNpemUKb3IgcGVyZm9ybWFuY2UgdHdlYWsuCgpUaGFua3MsCk1hcmsu CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpsaW51eC1h cm0ta2VybmVsIG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5v cmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9saW51eC1hcm0t a2VybmVsCg==