Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
Am 23.05.2018 um 19:07 schrieb Johannes Hirte: On 2018 Mai 23, Pavel Machek wrote: On Sat 2018-05-19 21:53:02, Christian Krüger wrote: Hi, Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 (known for being installed in many Netbooks and Nettops) are not sensitive for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these anyway "weak" CPUs from the costly patches by default? Browsing the web, I can "feel the difference" if the matching kernel options are applied on such a device. Can you also measure the difference? Placebo effect is hard to avoid. But yes, we do not need to do workarounds on non-buggy machines... Pavel On my Atom N270 there doesn't seem to be any workaround active with kernel 4.14.42: localhost ~ # cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Christian, did you verified the mitigations are active on your system? What kernels are affected? $ uname -a Linux user-device 3.13.0-143-generic #192-Ubuntu SMP Tue Feb 27 10:46:44 UTC 2018 i686 i686 i686 GNU/Linux $ cat /sys/devices/system/cpu/vulnerabilities/* Vulnerable Mittigation: OSB (observable speculation barrier, Intel v6) Mittigation: Full generic repoline OK, so I've updated the OS on my (usually off-line) Netbook: $ uname -a Linux user-device 3.13.0-149-generic #199-Ubuntu SMP Thu May 17 10:12:57 UTC 2018 i686 i686 i686 GNU/Linux $ cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Not affected Conclusion: Don't bother others before not checking the latest version. (Actually this is the first time it made a difference... ). Sorry for the noise and thanks for listening and all the great work! Christian
Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
Am 23.05.2018 um 19:07 schrieb Johannes Hirte: On 2018 Mai 23, Pavel Machek wrote: On Sat 2018-05-19 21:53:02, Christian Krüger wrote: Hi, Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 (known for being installed in many Netbooks and Nettops) are not sensitive for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these anyway "weak" CPUs from the costly patches by default? Browsing the web, I can "feel the difference" if the matching kernel options are applied on such a device. Can you also measure the difference? Placebo effect is hard to avoid. But yes, we do not need to do workarounds on non-buggy machines... Pavel On my Atom N270 there doesn't seem to be any workaround active with kernel 4.14.42: localhost ~ # cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Christian, did you verified the mitigations are active on your system? What kernels are affected? $ uname -a Linux user-device 3.13.0-143-generic #192-Ubuntu SMP Tue Feb 27 10:46:44 UTC 2018 i686 i686 i686 GNU/Linux $ cat /sys/devices/system/cpu/vulnerabilities/* Vulnerable Mittigation: OSB (observable speculation barrier, Intel v6) Mittigation: Full generic repoline OK, so I've updated the OS on my (usually off-line) Netbook: $ uname -a Linux user-device 3.13.0-149-generic #199-Ubuntu SMP Thu May 17 10:12:57 UTC 2018 i686 i686 i686 GNU/Linux $ cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Not affected Conclusion: Don't bother others before not checking the latest version. (Actually this is the first time it made a difference... ). Sorry for the noise and thanks for listening and all the great work! Christian
Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
On 2018 Mai 23, Pavel Machek wrote: > On Sat 2018-05-19 21:53:02, Christian Krüger wrote: > > Hi, > > > > Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 > > (known for being installed in many Netbooks and Nettops) are not sensitive > > for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these > > anyway "weak" CPUs from the costly patches by default? > > > > Browsing the web, I can "feel the difference" if the matching kernel options > > are applied on such a device. > > Can you also measure the difference? Placebo effect is hard to avoid. > > But yes, we do not need to do workarounds on non-buggy machines... > > Pavel On my Atom N270 there doesn't seem to be any workaround active with kernel 4.14.42: localhost ~ # cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Christian, did you verified the mitigations are active on your system? What kernels are affected? -- Regards, Johannes
Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
On 2018 Mai 23, Pavel Machek wrote: > On Sat 2018-05-19 21:53:02, Christian Krüger wrote: > > Hi, > > > > Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 > > (known for being installed in many Netbooks and Nettops) are not sensitive > > for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these > > anyway "weak" CPUs from the costly patches by default? > > > > Browsing the web, I can "feel the difference" if the matching kernel options > > are applied on such a device. > > Can you also measure the difference? Placebo effect is hard to avoid. > > But yes, we do not need to do workarounds on non-buggy machines... > > Pavel On my Atom N270 there doesn't seem to be any workaround active with kernel 4.14.42: localhost ~ # cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Christian, did you verified the mitigations are active on your system? What kernels are affected? -- Regards, Johannes
Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
On Sat 2018-05-19 21:53:02, Christian Krüger wrote: > Hi, > > Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 > (known for being installed in many Netbooks and Nettops) are not sensitive > for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these > anyway "weak" CPUs from the costly patches by default? > > Browsing the web, I can "feel the difference" if the matching kernel options > are applied on such a device. Can you also measure the difference? Placebo effect is hard to avoid. But yes, we do not need to do workarounds on non-buggy machines... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html signature.asc Description: Digital signature
Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
On Sat 2018-05-19 21:53:02, Christian Krüger wrote: > Hi, > > Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 > (known for being installed in many Netbooks and Nettops) are not sensitive > for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these > anyway "weak" CPUs from the costly patches by default? > > Browsing the web, I can "feel the difference" if the matching kernel options > are applied on such a device. Can you also measure the difference? Placebo effect is hard to avoid. But yes, we do not need to do workarounds on non-buggy machines... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html signature.asc Description: Digital signature
Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
Hi, Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 (known for being installed in many Netbooks and Nettops) are not sensitive for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these anyway "weak" CPUs from the costly patches by default? Browsing the web, I can "feel the difference" if the matching kernel options are applied on such a device. BR C.Krüger
Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?
Hi, Since the old "in-order-execution" Intel CPUs like the Intel Atom N270 (known for being installed in many Netbooks and Nettops) are not sensitive for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these anyway "weak" CPUs from the costly patches by default? Browsing the web, I can "feel the difference" if the matching kernel options are applied on such a device. BR C.Krüger
