From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Dan Magenheimer" Subject: RE: RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasing hvm guest time) Date: Fri, 4 Jul 2008 13:32:51 -0600 Message-ID: <20080704133251453.00000003744@djm-pc> References: Reply-To: "dan.magenheimer@oracle.com" Mime-Version: 1.0 Content-Type: multipart/mixed; boundary=-------2ea826dd2ea826dd Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser , "Xen-Devel (E-mail)" Cc: Dave Winchell List-Id: xen-devel@lists.xenproject.org This is a multi-part message in MIME format ---------2ea826dd2ea826dd Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable > On 4/7/08 16:11, "Dan Magenheimer" wrote: > = > > Oops, I misunderstood that for some reason. > > > > Here's a fixed version. I also now preserve the "Platform timer is" > > line since that can get flushed out of the dmesg buffer. OOPS, forgot the patch! Attached this time. > > Any idea why the skew can get so bad? > = > Not really. We could check in this patch or similar and = > perhaps collect more > information. > = > -- Keir Well one suspicion I had was that very long hpet reads were getting serialized, but I tried clocksource=3Dacpi and clocksource=3Dpit and get similar skew range results. In fact pit shows a max of >17000 vs hpet and acpi closer to 11000. (OTOH, I suppose it IS possible that this is roughly how long it takes to read each of these platform timers.) Dan ---------2ea826dd2ea826dd Content-Type: application/octet-stream; name="maxskew4.patch" Content-Disposition: attachment; filename="maxskew4.patch" Content-Transfer-Encoding: base64 ZGlmZiAtciAwOGY3N2RmMTRjYmEgeGVuL2FyY2gveDg2L2h2bS92cHQuYwotLS0gYS94ZW4v YXJjaC94ODYvaHZtL3ZwdC5jCVdlZCBKdWwgMDIgMTE6MzA6MzcgMjAwOCArMDkwMAorKysg Yi94ZW4vYXJjaC94ODYvaHZtL3ZwdC5jCUZyaSBKdWwgMDQgMDk6MDE6MjcgMjAwOCAtMDYw MApAQCAtMjUsNiArMjUsOCBAQAogI2RlZmluZSBtb2RlX2lzKGQsIG5hbWUpIFwKICAgICAo KGQpLT5hcmNoLmh2bV9kb21haW4ucGFyYW1zW0hWTV9QQVJBTV9USU1FUl9NT0RFXSA9PSBI Vk1QVE1fIyNuYW1lKQogCit1NjQgbWF4X2d1ZXN0X3RpbWVfc2tldyA9IDA7CisKIHZvaWQg aHZtX2luaXRfZ3Vlc3RfdGltZShzdHJ1Y3QgZG9tYWluICpkKQogewogICAgIHN0cnVjdCBw bF90aW1lICpwbCA9ICZkLT5hcmNoLmh2bV9kb21haW4ucGxfdGltZTsKQEAgLTM4LDE2ICs0 MCwyMiBAQCB1NjQgaHZtX2dldF9ndWVzdF90aW1lKHN0cnVjdCB2Y3B1ICp2KQogewogICAg IHN0cnVjdCBwbF90aW1lICpwbCA9ICZ2LT5kb21haW4tPmFyY2guaHZtX2RvbWFpbi5wbF90 aW1lOwogICAgIHU2NCBub3c7CisgICAgaW50NjRfdCBza2V3OwogCiAgICAgLyogQ2FsbGVk IGZyb20gZGV2aWNlIG1vZGVscyBzaGFyZWQgd2l0aCBQViBndWVzdHMuIEJlIGNhcmVmdWwu ICovCiAgICAgQVNTRVJUKGlzX2h2bV92Y3B1KHYpKTsKIAogICAgIHNwaW5fbG9jaygmcGwt PnBsX3RpbWVfbG9jayk7CiAgICAgbm93ID0gZ2V0X3NfdGltZSgpICsgcGwtPnN0aW1lX29m ZnNldDsKLSAgICBpZiAoIChpbnQ2NF90KShub3cgLSBwbC0+bGFzdF9ndWVzdF90aW1lKSA+ PSAwICkKKyAgICBpZiAoICggc2tldyA9IChpbnQ2NF90KShub3cgLSBwbC0+bGFzdF9ndWVz dF90aW1lKSApID49IDAgKQogICAgICAgICBwbC0+bGFzdF9ndWVzdF90aW1lID0gbm93Owog ICAgIGVsc2UKKyAgICB7CisgICAgICAgIHNrZXcgPSAtc2tldzsKKyAgICAgICAgaWYgKCBz a2V3ID4gbWF4X2d1ZXN0X3RpbWVfc2tldyApCisgICAgICAgICAgICBtYXhfZ3Vlc3RfdGlt ZV9za2V3ID0gc2tldzsKICAgICAgICAgbm93ID0gcGwtPmxhc3RfZ3Vlc3RfdGltZTsKKyAg ICB9CiAgICAgc3Bpbl91bmxvY2soJnBsLT5wbF90aW1lX2xvY2spOwogCiAgICAgcmV0dXJu IG5vdyArIHYtPmFyY2guaHZtX3ZjcHUuc3RpbWVfb2Zmc2V0OwpkaWZmIC1yIDA4Zjc3ZGYx NGNiYSB4ZW4vYXJjaC94ODYvdGltZS5jCi0tLSBhL3hlbi9hcmNoL3g4Ni90aW1lLmMJV2Vk IEp1bCAwMiAxMTozMDozNyAyMDA4ICswOTAwCisrKyBiL3hlbi9hcmNoL3g4Ni90aW1lLmMJ RnJpIEp1bCAwNCAwOTowMToyNyAyMDA4IC0wNjAwCkBAIC02OSw2ICs2OSwxMiBAQCBzdGF0 aWMgREVGSU5FX1BFUl9DUFUoc3RydWN0IGNwdV90aW1lLCBjCiAKIC8qIFRTQyBpcyBpbnZh cmlhbnQgb24gQyBzdGF0ZSBlbnRyeT8gKi8KIHN0YXRpYyBib29sX3QgdHNjX2ludmFyaWFu dDsKKworLyogZ2xvYmFsIHZhcmlhYmxlcyBleHBvcnRlZCB0byByZXBvcnQgd2l0aCBkZWJ1 Zy1rZXkgdCAqLwordTY0IG1heF9zdGltZV9za2V3ID0gMDsKK3U2NCBzdGltZV9za2V3X3pl cm9fY250ID0gMCxzdGltZV9za2V3XzEwX2NudCA9IDAsIHN0aW1lX3NrZXdfMTAwX2NudCA9 IDA7Cit1NjQgc3RpbWVfc2tld18xMDAwX2NudCA9IDAsc3RpbWVfc2tld18xMDAwMF9jbnQg PSAwLCBzdGltZV9za2V3X2JpZ19jbnQgPSAwOworY2hhciBwbGF0Zm9ybV90aW1lcl9pbmZv WzgwXTsKIAogLyoKICAqIFdlIHNpbXVsYXRlIGEgMzItYml0IHBsYXRmb3JtIHRpbWVyIGZy b20gdGhlIDE2LWJpdCBQSVQgY2gyIGNvdW50ZXIuCkBAIC01NjAsOCArNTY2LDEyIEBAIHN0 YXRpYyB2b2lkIGluaXRfcGxhdGZvcm1fdGltZXIodm9pZCkKIAogICAgIHBsYXRmb3JtX3Rp bWVyX3N0YW1wID0gcGx0X3N0YW1wNjQ7CiAKLSAgICBwcmludGsoIlBsYXRmb3JtIHRpbWVy IGlzICVzICVzXG4iLAorICAgIC8qIHByZXNlcnZlIGZvciB4bSBkZWJ1Zy1rZXkgJ3QnICov CisgICAgc25wcmludGYocGxhdGZvcm1fdGltZXJfaW5mbywgc2l6ZW9mKHBsYXRmb3JtX3Rp bWVyX2luZm8pLAorICAgICAgICAgICAiUGxhdGZvcm0gdGltZXIgaXMgJXMgJXMiLAogICAg ICAgICAgICBmcmVxX3N0cmluZyhwdHMtPmZyZXF1ZW5jeSksIHB0cy0+bmFtZSk7CisKKyAg ICBwcmludGsoIiVzXG4iLHBsYXRmb3JtX3RpbWVyX2luZm8pOwogfQogCiB2b2lkIGNzdGF0 ZV9zYXZlX3RzYyh2b2lkKQpAQCAtODA4LDYgKzgxOCw3IEBAIHN0YXRpYyB2b2lkIGxvY2Fs X3RpbWVfY2FsaWJyYXRpb24odm9pZCAKICAgICAgKi8KICAgICBzX3RpbWVfdCBwcmV2X2xv Y2FsX3N0aW1lLCBjdXJyX2xvY2FsX3N0aW1lOwogICAgIHNfdGltZV90IHByZXZfbWFzdGVy X3N0aW1lLCBjdXJyX21hc3Rlcl9zdGltZTsKKyAgICBzX3RpbWVfdCBjdXJyX3N0aW1lX3Nr ZXc7CiAKICAgICAvKiBUU0MgdGltZXN0YW1wcyB0YWtlbiBkdXJpbmcgdGhpcyBjYWxpYnJh dGlvbiBhbmQgcHJldiBjYWxpYnJhdGlvbi4gKi8KICAgICB1NjQgcHJldl90c2MsIGN1cnJf dHNjOwpAQCAtODMxLDYgKzg0Miw5IEBAIHN0YXRpYyB2b2lkIGxvY2FsX3RpbWVfY2FsaWJy YXRpb24odm9pZCAKICAgICAvKiBUaGUgb3ZlcmFsbCBjYWxpYnJhdGlvbiBzY2FsZSBtdWx0 aXBsaWVyLiAqLwogICAgIHUzMiBjYWxpYnJhdGlvbl9tdWxfZnJhYzsKIAorICAgIC8qIGln bm9yZSBtYXggc2tldyBjYWxjdWxhdGlvbiBvbiBmaXJzdCBmZXcgaXRlcmF0aW9ucyAqLwor ICAgIHN0YXRpYyBpbnQgc2tpcF9tYXhfc2tld19jYWxjID0gMTAwOworCiAgICAgcHJldl90 c2MgICAgICAgICAgPSB0LT5sb2NhbF90c2Nfc3RhbXA7CiAgICAgcHJldl9sb2NhbF9zdGlt ZSAgPSB0LT5zdGltZV9sb2NhbF9zdGFtcDsKICAgICBwcmV2X21hc3Rlcl9zdGltZSA9IHQt PnN0aW1lX21hc3Rlcl9zdGFtcDsKQEAgLTg0NCw2ICs4NTgsMzcgQEAgc3RhdGljIHZvaWQg bG9jYWxfdGltZV9jYWxpYnJhdGlvbih2b2lkIAogICAgIGN1cnJfbG9jYWxfc3RpbWUgID0g Z2V0X3NfdGltZSgpOwogICAgIHJkdHNjbGwoY3Vycl90c2MpOwogICAgIGxvY2FsX2lycV9l bmFibGUoKTsKKworICAgIC8qCisgICAgICogUmVjb3JkIG1heGltdW0gc3RpbWUgc2tldyBm cm9tIHBsYXRmb3JtIHRpbWVyLiAgTm90ZSB0aGF0CisgICAgICogaW4gdGhlIGNhc2Ugb2Yg YSBmYXN0IGxvY2FsIGNsb2NrLCBza2V3IHJlZmxlY3RzIHRoZSBwb3N0LWFkanVzdGVkCisg ICAgICogc2tldyAoc2VlIGJlbG93IGFuZCBnZXRfc190aW1lKCkpLCBub3QgdGhlIGFjdHVh bCBza2V3LiAgQWxzbworICAgICAqIG5vdGUgdGhhdCBzb21lIHByb2Nlc3NvcnMgbWF5IHNr ZXcgcG9zaXRpdmUgYW5kIG90aGVycyBuZWdhdGl2ZQorICAgICAqIHJlbGF0aXZlIHRvIHBs YXRmb3JtIHRpbWVyIHNvIHNrZXcgYmV0d2VlbiBBTlkgcGFpciBvZiBwcm9jZXNzb3JzIG1h eSBiZQorICAgICAqIGFzIG11Y2ggYXMgMnggcmVjb3JkZWQgbWF4CisgICAgICovCisgICAg aWYgKCBza2lwX21heF9za2V3X2NhbGMgPiAwKQorICAgICAgICBza2lwX21heF9za2V3X2Nh bGMtLTsgIC8qIGFsbG93IGNhbGlicmF0aW9uIHRvIGNvbnZlcmdlICovCisgICAgZWxzZQor ICAgIHsKKyAgICAgICAgY3Vycl9zdGltZV9za2V3ID0gY3Vycl9tYXN0ZXJfc3RpbWUgLSBj dXJyX2xvY2FsX3N0aW1lOworICAgICAgICBpZiAoIChzNjQpIGN1cnJfc3RpbWVfc2tldyA8 IDAgKQorICAgICAgICAgICAgY3Vycl9zdGltZV9za2V3ID0gLSBjdXJyX3N0aW1lX3NrZXc7 CisgICAgICAgIGlmICggY3Vycl9zdGltZV9za2V3ID4gbWF4X3N0aW1lX3NrZXcgKQorICAg ICAgICAgICAgbWF4X3N0aW1lX3NrZXcgPSBjdXJyX3N0aW1lX3NrZXc7CisgICAgICAgIGlm ICggIWN1cnJfc3RpbWVfc2tldyApCisgICAgICAgICAgICBzdGltZV9za2V3X3plcm9fY250 Kys7CisgICAgICAgIGVsc2UgaWYgKCBjdXJyX3N0aW1lX3NrZXcgPCAxMCApCisgICAgICAg ICAgICBzdGltZV9za2V3XzEwX2NudCsrOworICAgICAgICBlbHNlIGlmICggY3Vycl9zdGlt ZV9za2V3IDwgMTAwICkKKyAgICAgICAgICAgIHN0aW1lX3NrZXdfMTAwX2NudCsrOworICAg ICAgICBlbHNlIGlmICggY3Vycl9zdGltZV9za2V3IDwgMTAwMCApCisgICAgICAgICAgICBz dGltZV9za2V3XzEwMDBfY250Kys7CisgICAgICAgIGVsc2UgaWYgKCBjdXJyX3N0aW1lX3Nr ZXcgPCAxMDAwMCApCisJICAgIHN0aW1lX3NrZXdfMTAwMDBfY250Kys7CisgICAgICAgIGVs c2UKKyAgICAgICAgICAgIHN0aW1lX3NrZXdfYmlnX2NudCsrOworICAgIH0KIAogI2lmIDAK ICAgICBwcmludGsoIlBSRSVkOiB0c2M9JSJQUkl1NjQiIHN0aW1lPSUiUFJJdTY0IiBtYXN0 ZXI9JSJQUkl1NjQiXG4iLApkaWZmIC1yIDA4Zjc3ZGYxNGNiYSB4ZW4vY29tbW9uL2tleWhh bmRsZXIuYwotLS0gYS94ZW4vY29tbW9uL2tleWhhbmRsZXIuYwlXZWQgSnVsIDAyIDExOjMw OjM3IDIwMDggKzA5MDAKKysrIGIveGVuL2NvbW1vbi9rZXloYW5kbGVyLmMJRnJpIEp1bCAw NCAwOTowMToyNyAyMDA4IC0wNjAwCkBAIC0yNTEsNiArMjUxLDEwIEBAIHN0YXRpYyB2b2lk IHJlYWRfY2xvY2tzKHVuc2lnbmVkIGNoYXIga2UKICAgICB1bnNpZ25lZCBpbnQgY3B1ID0g c21wX3Byb2Nlc3Nvcl9pZCgpLCBtaW5fY3B1LCBtYXhfY3B1OwogICAgIHU2NCBtaW4sIG1h eCwgZGlmLCBkaWZ1czsKICAgICBzdGF0aWMgREVGSU5FX1NQSU5MT0NLKGxvY2spOworICAg IGV4dGVybiB1NjQgbWF4X3N0aW1lX3NrZXcsIG1heF9ndWVzdF90aW1lX3NrZXc7CisgICAg ZXh0ZXJuIHU2NCBzdGltZV9za2V3X3plcm9fY250LCBzdGltZV9za2V3XzEwX2NudCwgc3Rp bWVfc2tld18xMDBfY250OworICAgIGV4dGVybiB1NjQgc3RpbWVfc2tld18xMDAwX2NudCwg c3RpbWVfc2tld18xMDAwMF9jbnQsIHN0aW1lX3NrZXdfYmlnX2NudDsKKyAgICBleHRlcm4g Y2hhciBwbGF0Zm9ybV90aW1lcl9pbmZvWzgwXTsKIAogICAgIHNwaW5fbG9jaygmbG9jayk7 CiAKQEAgLTI4MSw5ICsyODUsMTggQEAgc3RhdGljIHZvaWQgcmVhZF9jbG9ja3ModW5zaWdu ZWQgY2hhciBrZQogCiAgICAgZGlmID0gZGlmdXMgPSBtYXggLSBtaW47CiAgICAgZG9fZGl2 KGRpZnVzLCAxMDAwKTsKKyAgICBwcmludGsoIiVzXG4iLHBsYXRmb3JtX3RpbWVyX2luZm8p OwogICAgIHByaW50aygiTWluID0gJSJQUkl1NjQiIDsgTWF4ID0gJSJQUkl1NjQiIDsgRGlm ZiA9ICUiUFJJdTY0CiAgICAgICAgICAgICIgKCUiUFJJdTY0IiBtaWNyb3NlY29uZHMpXG4i LAogICAgICAgICAgICBtaW4sIG1heCwgZGlmLCBkaWZ1cyk7CisgICAgcHJpbnRrKCJNYXgg c3RpbWUgc2tldyA9ICUiUFJJdTY0Im5zOyBNYXggZ3Vlc3Qgc3RvcHBhZ2UgPSAlIlBSSXU2 NCJuc1xuIiwKKyAgICAgICAgICAgbWF4X3N0aW1lX3NrZXcsIG1heF9ndWVzdF90aW1lX3Nr ZXcpOworICAgIHByaW50aygic3RpbWUgc2tldyBjb3VudHM6IDA9JSJQUkl1NjQiOyAiLHN0 aW1lX3NrZXdfemVyb19jbnQpOworICAgIHByaW50aygiLTEwPSUiUFJJdTY0IjsgIixzdGlt ZV9za2V3XzEwX2NudCk7CisgICAgcHJpbnRrKCItMTAwPSUiUFJJdTY0IjsgIixzdGltZV9z a2V3XzEwMF9jbnQpOworICAgIHByaW50aygiLTEwMDA9JSJQUkl1NjQiOyAiLHN0aW1lX3Nr ZXdfMTAwMF9jbnQpOworICAgIHByaW50aygiLTEwMDAwPSUiUFJJdTY0IjsgIixzdGltZV9z a2V3XzEwMDAwX2NudCk7CisgICAgcHJpbnRrKCI+MTAwMDA9JSJQUkl1NjQiXG4iLHN0aW1l X3NrZXdfYmlnX2NudCk7CiB9CiAKIGV4dGVybiB2b2lkIGR1bXBfcnVucSh1bnNpZ25lZCBj aGFyIGtleSk7Cg== ---------2ea826dd2ea826dd Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel ---------2ea826dd2ea826dd--