Babu Moger 215e562251 x86/resctrl: Fix memory bandwidth counter width for AMD ... commit 2c18bd525c upstream. Memory bandwidth is calculated reading the monitoring counter at two intervals and calculating the delta. It is the software’s responsibility to read the count often enough to avoid having the count roll over _twice_ between reads. The current code hardcodes the bandwidth monitoring counter's width to 24 bits for AMD. This is due to default base counter width which is 24. Currently, AMD does not implement the CPUID 0xF.[ECX=1]:EAX to adjust the counter width. But, the AMD hardware supports much wider bandwidth counter with the default width of 44 bits. Kernel reads these monitoring counters every 1 second and adjusts the counter value for overflow. With 24 bits and scale value of 64 for AMD, it can only measure up to 1GB/s without overflowing. For the rates above 1GB/s this will fail to measure the bandwidth. Fix the issue setting the default width to 44 bits by adjusting the offset. AMD future products will implement CPUID 0xF.[ECX=1]:EAX. [ bp: Let the line stick out and drop {}-brackets around a single statement. ] Fixes: 4d05bf71f1 ("x86/resctrl: Introduce AMD QOS feature") Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/159129975546.62538.5656031125604254041.stgit@naples-babu.amd.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-07-09 09:37:57 +02:00
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Makefile	x86/resctrl: Avoid confusion over the new X86_RESCTRL config	2019-02-02 10:34:52 +01:00
core.c	x86/resctrl: Fix memory bandwidth counter width for AMD	2020-07-09 09:37:57 +02:00
ctrlmondata.c	x86/resctrl: Prevent NULL pointer dereference when reading mondata	2019-11-03 17:51:22 +01:00
internal.h	x86/resctrl: Fix memory bandwidth counter width for AMD	2020-07-09 09:37:57 +02:00
monitor.c	x86/resctrl: Fix memory bandwidth counter width for AMD	2020-07-09 09:37:57 +02:00
pseudo_lock.c	Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-07-08 17:25:53 -07:00
pseudo_lock_event.h	x86/resctrl: Rename and move rdt files to a separate directory	2018-11-22 20:16:18 +01:00
rdtgroup.c	x86/resctrl: Fix a NULL vs IS_ERR() static checker warning in rdt_cdp_peer_get()	2020-06-30 15:36:56 -04:00