Optimize getppid

kaist-cp · Apr 8, 2022 · 9094820 · 9094820
1 parent c0142a1
commit 9094820
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Showing 7 changed files with 81 additions and 43 deletions.
diff --git a/kernel-rs/Cargo.toml b/kernel-rs/Cargo.toml
@@ -21,7 +21,7 @@ opt-level = 1
 
 [profile.release]
 panic = "abort"
-opt-level = 1
+opt-level = 2
 
 [dependencies]
 array-macro = "2.1.0"

diff --git a/kernel-rs/src/arch/arm/trap.rs b/kernel-rs/src/arch/arm/trap.rs
@@ -16,7 +16,6 @@ use crate::{
         timer::set_next_timer,
         Armv8,
     },
-    kernel::TIME,
     // kernel::KERNEL,
     memlayout::{TRAMPOLINE, TRAPFRAME},
     trap::{IrqNum, IrqTypes, TrapTypes},
@@ -198,7 +197,7 @@ impl TrapManager for Armv8 {
         trapframe: &mut TrapFrame,
         kernel_stack: usize,
         usertrap: usize,
-        syscall_num: usize,
+        _syscall_num: usize,
     ) -> ! {
         // We're about to switch the destination of traps from
         // kerneltrap() to usertrap(), so turn off interrupts until
@@ -228,22 +227,22 @@ impl TrapManager for Armv8 {
         // }
 
         // If it is getppid, print elapsed time per interval.
-        if _syscall_num == 26 {
-            unsafe {
-                crate::kernel::kernel_ref(|kctx| {
-                    for i in 0..2 {
-                        kctx.as_ref().write_fmt(format_args!(
-                            "Interval {}: {}\n",
-                            i + 1,
-                            TIME[i + 1] - TIME[i]
-                        ));
-                    }
-                    // for i in 0..4{
-                    //     kctx.as_ref().write_fmt(format_args!("lap {}: {}\n", i, TIME[i]));
-                    // }
-                })
-            }
-        }
+        // if _syscall_num == 26 {
+        //     unsafe {
+        //         crate::kernel::kernel_ref(|kctx| {
+        //             // for i in 0..8 {
+        //                 kctx.as_ref().write_fmt(format_args!(
+        //                     "Interval {}: {}\n",
+        //                     0,
+        //                     TIME[0] - TIME[9]
+        //                 ));
+        //             // }
+        //             // for i in 0..4{
+        //             //     kctx.as_ref().write_fmt(format_args!("lap {}: {}\n", i, TIME[i]));
+        //             // }
+        //         })
+        //     }
+        // }
 
         unsafe { fn_0(TRAPFRAME, user_pagetable_addr) }
     }

diff --git a/kernel-rs/src/proc/procs.rs b/kernel-rs/src/proc/procs.rs
@@ -14,6 +14,7 @@ use super::*;
 use crate::{
     addr::{Addr, UVAddr, PGSIZE},
     arch::interface::TrapFrameManager,
+    arch::TargetArch,
     fs::{DefaultFs, FileSystem, FileSystemExt},
     hal::hal,
     kalloc::Kmem,
@@ -466,10 +467,29 @@ impl<'id, 's> ProcsRef<'id, 's> {
 
     // get the pid of current process's parent
     pub fn get_parent_pid(&self, ctx: &mut KernelCtx<'id, '_>) -> Pid {
+        // let before = TargetArch::r_cycle();
         let mut parent_guard = self.wait_guard();
+
+        // let after = TargetArch::r_cycle();
+
+        // ctx.kernel().as_ref().write_fmt(format_args!("lap1: {}\n", after - before));
+
+        // let before = TargetArch::r_cycle();
+
         let parent = *ctx.proc().get_mut_parent(&mut parent_guard);
 
+        // let after = TargetArch::r_cycle();
+
+        // ctx.kernel().as_ref().write_fmt(format_args!("lap2: {}\n", after - before));
+
+        // let before = TargetArch::r_cycle();
+
         let lock = unsafe { (*parent).info.lock() };
+
+        // let after = TargetArch::r_cycle();
+
+        // ctx.kernel().as_ref().write_fmt(format_args!("lap3: {}\n", after - before));
+
         lock.pid
     }
 }

diff --git a/kernel-rs/src/syscall.rs b/kernel-rs/src/syscall.rs
@@ -16,7 +16,6 @@ use crate::{
     file::{RcFile, SeekWhence, SelectEvent},
     fs::{FcntlFlags, FileSystem, FileSystemExt, InodeType, Path},
     hal::hal,
-    kernel::TIME,
     ok_or,
     page::{Page, PGSIZE},
     param::{MAXARG, MAXPATH},
@@ -90,11 +89,11 @@ impl CurrentProc<'_, '_> {
 
 impl KernelCtx<'_, '_> {
     pub fn syscall(&mut self, num: i32) -> Result<usize, ()> {
-        let clock = TargetArch::r_cycle();
+        // let clock = TargetArch::r_cycle();
         // record end of stage 2 (begin of stage 3).
-        unsafe {
-            TIME[1] = clock;
-        }
+        // unsafe {
+        //     TIME[1] = clock;
+        // }
         let ret = match num {
             1 => self.sys_fork(),
             2 => self.sys_exit(),
@@ -136,11 +135,11 @@ impl KernelCtx<'_, '_> {
             }
         };
 
-        let clock = TargetArch::r_cycle();
+        // let clock = TargetArch::r_cycle();
         // record end of stage 3 (begin of stage 4).
-        unsafe {
-            TIME[2] = clock;
-        }
+        // unsafe {
+        //     TIME[2] = clock;
+        // }
         ret
     }
 

diff --git a/kernel/arm/trampoline.S b/kernel/arm/trampoline.S
@@ -5,14 +5,6 @@
 .globl trampoline
 trampoline:
 
-.macro flush_cache
-	isb     sy
-        dsb     sy
-        dsb     ishst
-        tlbi    vmalle1is
-        dsb     ish
-        isb
-.endm
 
 .macro	exception_1_entry
 	sub	sp, sp, #272
@@ -143,8 +135,12 @@ trampoline:
 
         msr     ttbr0_el1, x24
 
+		mrs		x3, cntpct_el0
+		msr		tpidr_el0, x3
+
         # flush all the caches
-        flush_cache
+		tlbi    vmalle1is
+		isb
 .endm
 
 /* Exception vectors */
@@ -194,7 +190,9 @@ userret:
         # switch to the user page table.
         msr ttbr0_el1, x1
 
-        flush_cache
+        dsb     nsh
+		tlbi    vmalle1is
+		isb
 
         # restore ELR, SPSR, LR, SP
 	ldp	x21, x22, [x0, #16]      /* SPSR, FPSR */

diff --git a/lmbench/lat_syscall.c b/lmbench/lat_syscall.c
@@ -35,7 +35,8 @@ do_getppid(iter_t iterations, void *cookie)
 		getppid();
 		// end of total execution
 		// x2 = read_cntpct();
-		// printf("total: %lu\n", x2 - x1);
+		// printf("x1: %lu, x2: %lu\n", x1, x2);
+		// printf("diff: %lu\n", x2 - x1);
 	}	
 }
 

diff --git a/user/ulib.c b/user/ulib.c
@@ -4,6 +4,7 @@
 #include "user/user.h"
 
 #define MICROSECS_PER_TICK 100000
+#define US_PER_S 1000000
 
 char*
 strcpy(char *s, const char *t)
@@ -275,13 +276,33 @@ int fsync(int fildes)
 //   return 0;
 // }
 
-// TODO: find better way to convert uptime ticks to real time.
+// TODO: This is only for aarch64. Separate this.
+static inline uint64 r_cntpct() {
+	uint64 x;
+	asm volatile("isb sy");
+	asm volatile("mrs %0, CNTPCT_EL0" : "=r" (x));
+	asm volatile("isb sy");
+	return x;
+}
+
+
+// TODO: This is only for aarch64. Separate this.
+static inline uint64 r_freq() {
+	uint64 x;
+  asm volatile("isb sy");
+	asm volatile("mrs %0, CNTFRQ_EL0" : "=r" (x));
+	asm volatile("isb sy");
+  return x;
+}
+
+// TODO: optimize this not to use floating point operations (Linux timekeeper).
+// user-level uptime syscall
 int gettimeofday(struct timeval *__restrict__ tp, 
                 struct timezone *__restrict__ tzp)
 {
-  int cur = uptime_as_micro();
-  tp->tv_sec = cur / 1000000;
-  tp->tv_usec = cur % 1000000;
+  uint64 uptime_in_micro = (r_cntpct() * US_PER_S) / r_freq();
+  tp->tv_sec = uptime_in_micro / US_PER_S;
+  tp->tv_usec = uptime_in_micro % US_PER_S;
   return 0;
 }