Alexander Shishkin 9a6694cfa2 perf/x86/intel/pt: Do not force sync packets on every schedule-in ... Currently, the PT driver zeroes out the status register every time before starting the event. However, all the writable bits are already taken care of in pt_handle_status() function, except the new PacketByteCnt field, which in new versions of PT contains the number of packet bytes written since the last sync (PSB) packet. Zeroing it out before enabling PT forces a sync packet to be written. This means that, with the existing code, a sync packet (PSB and PSBEND, 18 bytes in total) will be generated every time a PT event is scheduled in. To avoid these unnecessary syncs and save a WRMSR in the fast path, this patch changes the default behavior to not clear PacketByteCnt field, so that the sync packets will be generated with the period specified as "psb_period" attribute config field. This has little impact on the trace data as the other packets that are normally sent within PSB+ (between PSB and PSBEND) have their own generation scenarios which do not depend on the sync packets. One exception where we do need to force PSB like this when tracing starts, so that the decoder has a clear sync point in the trace. For this purpose we aready have hw::itrace_started flag, which we are currently using to output PERF_RECORD_ITRACE_START. This patch moves setting itrace_started from perf core to the pmu::start, where it should still be 0 on the very first run. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@infradead.org Cc: adrian.hunter@intel.com Cc: hpa@zytor.com Link: http://lkml.kernel.org/r/1438264104-16189-1-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2015-08-04 10:16:55 +02:00
..
alpha	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
arc	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
arm	MMC core:	2015-07-24 16:43:16 -07:00
arm64	ARM64/irq: Use access helper irq_data_get_affinity_mask()	2015-07-22 10:57:09 +01:00
avr32	AVR32/time: Migrate to new 'set-state' interface	2015-07-20 12:19:10 +02:00
blackfin	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
c6x	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
cris	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
frv	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
h8300	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
hexagon	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
ia64	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
m32r	m32r: Add ioreadXX/iowriteXX big-endian mmio accessors	2015-07-23 18:08:28 -07:00
m68k	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
metag	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
microblaze	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
mips	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2015-07-19 14:12:22 -07:00
mn10300	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
nios2	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
openrisc	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
parisc	parisc: mm: Fix a memory leak related to pmd not attached to the pgd	2015-07-19 08:56:14 +02:00
powerpc	powerpc/perf/24x7: Fix lockdep warning	2015-07-08 15:18:04 +10:00
s390	s390: adapt entry.S to the move of thread_struct	2015-07-20 13:22:18 +02:00
score	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
sh	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
sparc	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
tile	tile: use free_bootmem_late() for initrd	2015-07-23 14:11:09 -04:00
um	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
unicore32	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
x86	perf/x86/intel/pt: Do not force sync packets on every schedule-in	2015-08-04 10:16:55 +02:00
xtensa	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
.gitignore
Kconfig	x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86	2015-07-18 03:42:51 +02:00