Hi Christian, On Wed, Mar 13, 2019 at 5:27 PM Christian Gmeiner <[email protected]> wrote: > > Hi all, > > Am Mo., 11. März 2019 um 15:41 Uhr schrieb Bin Meng <[email protected]>: > > > > Hi Andy, > > > > On Wed, Mar 6, 2019 at 7:09 PM Andy Shevchenko > > <[email protected]> wrote: > > > > > > On Thu, Feb 28, 2019 at 11:29:50AM +0800, Bin Meng wrote: > > > > On Thu, May 24, 2018 at 12:00 PM Bin Meng <[email protected]> wrote: > > > > > On Thu, Apr 12, 2018 at 4:07 PM, Christian Gmeiner > > > > > <[email protected]> wrote: > > > > > > > So to me this seems to match my understanding about EIST. If this is > > > > true, then I can't explain why Christian's patch is needed since the > > > > EIST is disabled on TunnelCreek by default and the processor should > > > > already run at the highest performance. > > > > > > The some internal documents I found suggesting that first what one needs > > > to do > > > is to be sure that EIST is enabled / disabled by reading a bit from CPUID. > > > > > > > Correct. This is documented in the public Intel SDM too. > > > > > (There is no mention of the exact bit, I'm guessing it might be > > > X86_FEATURE_EST) > > > > > > It also refers to IA32_MISC_ENABLE MSR, i.e. bit 20 > > > (MSR_IA32_MISC_ENABLE_SPEEDSTEP_LOCK_BIT) and bit 16 > > > (MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP_BIT), that firmware can set up > > > accordingly. > > > > > > Hope this helps. > > > > > > > Thanks for the help. But I was looking for clarification on what > > frequency the CPU is running at if EIST is disabled (the default > > power-up state). Especially I suspect the Intel CPU is running at the > > highest frequency when ESIT is disabled hence the highest performance. > > Such details are not documented in the public Intel SDM. :( > > > > > P.S. All names are implying Linux kernel source code. > > > > I think I need to clarify how I came to this patch. > > Back in the days when we used an Intel BLDK based BIOS solution we did > some performance > measurements and found out that the same device with an vendor BIOS is > much faster. So we started > to dig into the issue and used bandwidth to do our measurements. We > contacted Intel to get support > and after lot of ping-pong mails we got a solution. > > We need to set these two msr registers to the values they provided to us. > These msr register should be described in #29324.
Could you please provide details about these 2 MSR registers? And is there any official document from Intel about what is the behavior of having EIST disabled? > > Bin do you have hardware to reproduce this issue I have and what gets > fixed with this patch? Yes, I have the hardware to test. Is the test case able to run in U-Boot? I can have a test. Regards, Bin _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
