diff options
| author | Damien Zammit <damien@zamaudio.com> | 2023-09-24 10:35:10 +0000 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2023-09-24 14:38:03 +0200 |
| commit | b11e10e2c81c2b608176021364a36d84173358e3 (patch) | |
| tree | 8bde3f47151865143341e864040af3bde68385a5 /x86_64 | |
| parent | 31d45d0d8ee1d8eee96fc2a283a388b6b6aca669 (diff) | |
percpu area using gs segment
This speeds up smp again, by storing the struct processor
in a percpu area and avoiding an expensive cpu_number every call
of current_processor(), as well as getting the cpu_number by
an offset into the percpu area. Untested on 64 bit
and work remains to use other percpu arrays.
TESTED: (NCPUS=8) -smp 1 boots to login shell ~2x slower than uniprocessor
TESTED: (NCPUS=8) -smp 2 boots to INIT but hangs there
TESTED: (NCPUS=8) -smp 4 gets stuck seemingly within rumpdisk and hangs
TESTED: (NCPUS=1) uniprocessor is a bit faster than normal
Message-Id: <20230924103428.455966-3-damien@zamaudio.com>
Diffstat (limited to 'x86_64')
| -rw-r--r-- | x86_64/Makefrag.am | 2 | ||||
| -rw-r--r-- | x86_64/locore.S | 7 |
2 files changed, 6 insertions, 3 deletions
diff --git a/x86_64/Makefrag.am b/x86_64/Makefrag.am index 008ac58f..0c67517c 100644 --- a/x86_64/Makefrag.am +++ b/x86_64/Makefrag.am @@ -103,6 +103,8 @@ libkernel_a_SOURCES += \ i386/i386/irq.c \ i386/i386/irq.h \ i386/i386/msr.h \ + i386/i386/percpu.h \ + i386/i386/percpu.c \ i386/i386/pit.c \ i386/i386/pit.h diff --git a/x86_64/locore.S b/x86_64/locore.S index fabbf2e7..d640ef73 100644 --- a/x86_64/locore.S +++ b/x86_64/locore.S @@ -140,6 +140,7 @@ mov %dx,%ds ;\ mov %dx,%es ;\ mov %dx,%fs ;\ + mov $(PERCPU_DS),%dx ;\ mov %dx,%gs #else #define SET_KERNEL_SEGMENTS @@ -350,7 +351,7 @@ timer_normalize: * Switch to a new timer. */ ENTRY(timer_switch) - CPU_NUMBER(%edx) /* get this CPU */ + CPU_NUMBER_NO_GS(%edx) /* get this CPU */ movl VA_ETC,%ecx /* get timer */ movl CX(EXT(current_tstamp),%rdx),%eax /* get old time stamp */ movl %ecx,CX(EXT(current_tstamp),%rdx) /* set new time stamp */ @@ -368,7 +369,7 @@ ENTRY(timer_switch) * Initialize the first timer for a CPU. */ ENTRY(start_timer) - CPU_NUMBER(%edx) /* get this CPU */ + CPU_NUMBER_NO_GS(%edx) /* get this CPU */ movl VA_ETC,%ecx /* get timer */ movl %ecx,CX(EXT(current_tstamp),%rdx) /* set initial time stamp */ movl S_ARG0,%ecx /* get timer */ @@ -1445,7 +1446,7 @@ _syscall64_call: _syscall64_check_for_ast: /* Check for ast. */ - CPU_NUMBER(%r11) + CPU_NUMBER_NO_GS(%r11) cmpl $0,CX(EXT(need_ast),%r11) jz _syscall64_restore_state |