Re: [v1 0/9] Early boot time stamps for x86

2017-03-23 Thread Thomas Gleixner
On Thu, 23 Mar 2017, Pasha Tatashin wrote: > I will add a condition to tsc_early_init() to check for TSC_ADJUST if it is > not 0, disable early TSC feature. Does this sound OK? Not really. I have strong objections against how this is crammed into the early boot process along with the code

Re: [v1 0/9] Early boot time stamps for x86

2017-03-23 Thread Thomas Gleixner
On Thu, 23 Mar 2017, Pasha Tatashin wrote: > I will add a condition to tsc_early_init() to check for TSC_ADJUST if it is > not 0, disable early TSC feature. Does this sound OK? Not really. I have strong objections against how this is crammed into the early boot process along with the code

Re: [v1 0/9] Early boot time stamps for x86

2017-03-23 Thread Pasha Tatashin
Hi Thomas, Thank you very much for looking at this patchset. Comments below: On 03/23/2017 06:56 AM, Thomas Gleixner wrote: On Wed, 22 Mar 2017, Pasha Tatashin wrote: Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I Emphasis on "this machine' It's not guaranteed

Re: [v1 0/9] Early boot time stamps for x86

2017-03-23 Thread Pasha Tatashin
Hi Thomas, Thank you very much for looking at this patchset. Comments below: On 03/23/2017 06:56 AM, Thomas Gleixner wrote: On Wed, 22 Mar 2017, Pasha Tatashin wrote: Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I Emphasis on "this machine' It's not guaranteed

Re: [v1 0/9] Early boot time stamps for x86

2017-03-23 Thread Thomas Gleixner
On Wed, 22 Mar 2017, Pasha Tatashin wrote: > Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I Emphasis on "this machine' It's not guaranteed especially not on reboot and not with creative BIOSes fiddling with the TSC_ADJUST value. - It CANNOT be used to measure BIOS

Re: [v1 0/9] Early boot time stamps for x86

2017-03-23 Thread Thomas Gleixner
On Wed, 22 Mar 2017, Pasha Tatashin wrote: > Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I Emphasis on "this machine' It's not guaranteed especially not on reboot and not with creative BIOSes fiddling with the TSC_ADJUST value. - It CANNOT be used to measure BIOS

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Pasha Tatashin
On 2017-03-22 16:27, Peter Zijlstra wrote: On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: Last week I sent out patches to enable early boot time stamp on SPARC, that work is now under review: http://www.spinics.net/lists/sparclinux/msg17372.html This is continuation for that

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Pasha Tatashin
On 2017-03-22 16:27, Peter Zijlstra wrote: On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: Last week I sent out patches to enable early boot time stamp on SPARC, that work is now under review: http://www.spinics.net/lists/sparclinux/msg17372.html This is continuation for that

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Pasha Tatashin
Hi Peter, Thank you for looking at this patchset. Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I actually wondered about it, and used stop watch as an alternative way to verify the result, twice. While, I suspect it is often the case that on reset tsc is 0, it is

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Pasha Tatashin
Hi Peter, Thank you for looking at this patchset. Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I actually wondered about it, and used stop watch as an alternative way to verify the result, twice. While, I suspect it is often the case that on reset tsc is 0, it is

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Peter Zijlstra
On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: > Last week I sent out patches to enable early boot time stamp on SPARC, that > work is now under review: > http://www.spinics.net/lists/sparclinux/msg17372.html > > This is continuation for that work, but adding early boot time

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Peter Zijlstra
On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: > Last week I sent out patches to enable early boot time stamp on SPARC, that > work is now under review: > http://www.spinics.net/lists/sparclinux/msg17372.html > > This is continuation for that work, but adding early boot time

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Peter Zijlstra
On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: > - early tsc offset is 549s, so it took over 9 minutes to get through POST, > and GRUB before starting linux Lol, how cute. You assume TSC starts at 0 on reset.

Re: [v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Peter Zijlstra
On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: > - early tsc offset is 549s, so it took over 9 minutes to get through POST, > and GRUB before starting linux Lol, how cute. You assume TSC starts at 0 on reset.

[v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Pavel Tatashin
Last week I sent out patches to enable early boot time stamp on SPARC, that work is now under review: http://www.spinics.net/lists/sparclinux/msg17372.html This is continuation for that work, but adding early boot time stamps support for x86 machines. Here is example how this information is

[v1 0/9] Early boot time stamps for x86

2017-03-22 Thread Pavel Tatashin
Last week I sent out patches to enable early boot time stamp on SPARC, that work is now under review: http://www.spinics.net/lists/sparclinux/msg17372.html This is continuation for that work, but adding early boot time stamps support for x86 machines. Here is example how this information is