Messages in this thread | | | Subject | RE: detecting hyperthreading in linux 2.4.19 | Date | Thu, 9 Jan 2003 15:26:38 -0800 | From | "Pallipadi, Venkatesh" <> |
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Systems running the latest RH, SuSE releases, with standard smp kernel should see some entries in /proc/cpuinfo, which gives information about HT configuration on the system. The latest 2.5 kernel also has similar information in /proc/cpuinfo. The entries look something like: Physical processor ID : 0 Number of siblings : 2
Unfortunately, 2.4.19 doesn't have such information. One possible workaround is to check big enough 'dmesg' and look for cpu_sibling_map. That tells you the mapping of logical processors to physical package. Or you can have a init script like this (attached) in place, to run at boot time, so that you have a better chance of finding these particular messages in log (without overflowing).
HTH, Venkatesh
------------------- #!/bin/sh # checkht kernel RC file. # # chkconfig: 35 98 98 # description: check for hyperthreaded CPUs
HASHT=`/bin/dmesg | /bin/grep cpu_sibling_map`
if [ -n "$HASHT" ]; then /bin/echo "Machine is running HT" /bin/echo 1 > /etc/hyperthreaded else /bin/echo "Machine isn't running HT" /bin/echo 0 > /etc/hyperthreaded Fi --------------
> -----Original Message----- > From: Jason Lunz [mailto:lunz@falooley.org] > Sent: Thursday, January 09, 2003 12:03 PM > To: linux-kernel@vger.kernel.org > Subject: detecting hyperthreading in linux 2.4.19 > > > Is there a way for a userspace program running on linux 2.4.19 to tell > the difference between a single hyperthreaded xeon P4 with HT enabled > and a dual hyperthreaded xeon P4 with HT disabled? The /proc/cpuinfos > for the two cases are indistinguishable. > > Jason > > - > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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