diff --git a/libc/arch-arm/krait/bionic/__strcat_chk.S b/libc/arch-arm/krait/bionic/__strcat_chk.S
index 246f159..1a39c5b 100644
--- a/libc/arch-arm/krait/bionic/__strcat_chk.S
+++ b/libc/arch-arm/krait/bionic/__strcat_chk.S
@@ -40,7 +40,7 @@
 ENTRY(__strcat_chk)
     pld     [r0, #0]
     push    {r0, lr}
-    .cfi_def_cfa_offset 8
+    .cfi_adjust_cfa_offset 8
     .cfi_rel_offset r0, 0
     .cfi_rel_offset lr, 4
     push    {r4, r5}
@@ -177,7 +177,7 @@
 .L_strlen_done:
     add     r2, r3, r4
     cmp     r2, lr
-    bhi     __strcat_chk_failed
+    bhi     .L_strcat_chk_failed
 
     // Set up the registers for the memcpy code.
     mov     r1, r5
@@ -185,20 +185,17 @@
     mov     r2, r4
     add     r0, r0, r3
     pop     {r4, r5}
-END(__strcat_chk)
+    .cfi_adjust_cfa_offset -8
+    .cfi_restore r4
+    .cfi_restore r5
 
-#define MEMCPY_BASE         __strcat_chk_memcpy_base
-#define MEMCPY_BASE_ALIGNED __strcat_chk_memcpy_base_aligned
 #include "memcpy_base.S"
 
-ENTRY_PRIVATE(__strcat_chk_failed)
-    .cfi_def_cfa_offset 8
-    .cfi_rel_offset r0, 0
-    .cfi_rel_offset lr, 4
+    // Undo the above cfi directives.
     .cfi_adjust_cfa_offset 8
     .cfi_rel_offset r4, 0
     .cfi_rel_offset r5, 4
-
+.L_strcat_chk_failed:
     ldr     r0, error_message
     ldr     r1, error_code
 1:
@@ -208,7 +205,7 @@
     .word   BIONIC_EVENT_STRCAT_BUFFER_OVERFLOW
 error_message:
     .word   error_string-(1b+4)
-END(__strcat_chk_failed)
+END(__strcat_chk)
 
     .data
 error_string:
diff --git a/libc/arch-arm/krait/bionic/__strcpy_chk.S b/libc/arch-arm/krait/bionic/__strcpy_chk.S
index db76686..00202f3 100644
--- a/libc/arch-arm/krait/bionic/__strcpy_chk.S
+++ b/libc/arch-arm/krait/bionic/__strcpy_chk.S
@@ -39,7 +39,7 @@
 ENTRY(__strcpy_chk)
     pld     [r0, #0]
     push    {r0, lr}
-    .cfi_def_cfa_offset 8
+    .cfi_adjust_cfa_offset 8
     .cfi_rel_offset r0, 0
     .cfi_rel_offset lr, 4
 
@@ -149,21 +149,14 @@
     pld     [r1, #64]
     ldr     r0, [sp]
     cmp     r3, lr
-    bhs     __strcpy_chk_failed
+    bhs     .L_strcpy_chk_failed
 
     // Add 1 for copy length to get the string terminator.
     add     r2, r3, #1
-END(__strcpy_chk)
 
-#define MEMCPY_BASE         __strcpy_chk_memcpy_base
-#define MEMCPY_BASE_ALIGNED __strcpy_chk_memcpy_base_aligned
 #include "memcpy_base.S"
 
-ENTRY_PRIVATE(__strcpy_chk_failed)
-    .cfi_def_cfa_offset 8
-    .cfi_rel_offset r0, 0
-    .cfi_rel_offset lr, 4
-
+.L_strcpy_chk_failed:
     ldr     r0, error_message
     ldr     r1, error_code
 1:
@@ -173,7 +166,7 @@
     .word   BIONIC_EVENT_STRCPY_BUFFER_OVERFLOW
 error_message:
     .word   error_string-(1b+4)
-END(__strcpy_chk_failed)
+END(__strcpy_chk)
 
     .data
 error_string:
diff --git a/libc/arch-arm/krait/bionic/memcpy.S b/libc/arch-arm/krait/bionic/memcpy.S
index 9ff46a8..5d27b57 100644
--- a/libc/arch-arm/krait/bionic/memcpy.S
+++ b/libc/arch-arm/krait/bionic/memcpy.S
@@ -45,7 +45,7 @@
 
 ENTRY(__memcpy_chk)
         cmp         r2, r3
-        bhi         __memcpy_chk_fail
+        bhi         .L_memcpy_chk_fail
 
         // Fall through to memcpy...
 END(__memcpy_chk)
@@ -53,19 +53,20 @@
 ENTRY(memcpy)
         pld     [r1, #64]
         stmfd   sp!, {r0, lr}
-        .cfi_def_cfa_offset 8
+        .cfi_adjust_cfa_offset 8
         .cfi_rel_offset r0, 0
         .cfi_rel_offset lr, 4
-END(memcpy)
 
-#define MEMCPY_BASE         __memcpy_base
-#define MEMCPY_BASE_ALIGNED __memcpy_base_aligned
 #include "memcpy_base.S"
 
-ENTRY_PRIVATE(__memcpy_chk_fail)
+        // Undo the cfi directives from above.
+        .cfi_adjust_cfa_offset -8
+        .cfi_restore r0
+        .cfi_restore lr
+.L_memcpy_chk_fail:
         // Preserve lr for backtrace.
         push    {lr}
-        .cfi_def_cfa_offset 4
+        .cfi_adjust_cfa_offset 4
         .cfi_rel_offset lr, 0
 
         ldr     r0, error_message
@@ -77,7 +78,7 @@
         .word   BIONIC_EVENT_MEMCPY_BUFFER_OVERFLOW
 error_message:
         .word   error_string-(1b+4)
-END(__memcpy_chk_fail)
+END(memcpy)
 
         .data
 error_string:
diff --git a/libc/arch-arm/krait/bionic/memcpy_base.S b/libc/arch-arm/krait/bionic/memcpy_base.S
index 6c098ac..76c5a84 100644
--- a/libc/arch-arm/krait/bionic/memcpy_base.S
+++ b/libc/arch-arm/krait/bionic/memcpy_base.S
@@ -1,122 +1,191 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
+/***************************************************************************
+ Copyright (c) 2009-2013 The Linux Foundation. All rights reserved.
 
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+     * Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+     * Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+     * Neither the name of The Linux Foundation nor the names of its contributors may
+       be used to endorse or promote products derived from this software
+       without specific prior written permission.
 
-/*
- * This code assumes it is running on a processor that supports all arm v7
- * instructions, that supports neon instructions, and that has a 32 byte
- * cache line.
- */
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ POSSIBILITY OF SUCH DAMAGE.
+  ***************************************************************************/
 
-// Assumes neon instructions and a cache line size of 32 bytes.
+/* Assumes neon instructions and a cache line size of 64 bytes. */
 
-ENTRY_PRIVATE(MEMCPY_BASE)
-        .cfi_def_cfa_offset 8
-        .cfi_rel_offset r0, 0
-        .cfi_rel_offset lr, 4
+#include <machine/cpu-features.h>
+#include <machine/asm.h>
 
-        /* do we have at least 16-bytes to copy (needed for alignment below) */
-        cmp         r2, #16
-        blo         5f
+#define PLDOFFS	(10)
+#define PLDTHRESH (PLDOFFS)
+#define BBTHRESH (4096/64)
+#define PLDSIZE (64)
 
-        /* align destination to cache-line for the write-buffer */
-        rsb         r3, r0, #0
-        ands        r3, r3, #0xF
-        beq         2f
+#if (PLDOFFS < 1)
+#error Routine does not support offsets less than 1
+#endif
 
-        /* copy up to 15-bytes (count in r3) */
-        sub         r2, r2, r3
-        movs        ip, r3, lsl #31
-        itt         mi
-        ldrbmi      lr, [r1], #1
-        strbmi      lr, [r0], #1
-        itttt       cs
-        ldrbcs      ip, [r1], #1
-        ldrbcs      lr, [r1], #1
-        strbcs      ip, [r0], #1
-        strbcs      lr, [r0], #1
-        movs        ip, r3, lsl #29
-        bge         1f
-        // copies 4 bytes, destination 32-bits aligned
-        vld4.8      {d0[0], d1[0], d2[0], d3[0]}, [r1]!
-        vst4.8      {d0[0], d1[0], d2[0], d3[0]}, [r0, :32]!
-1:      bcc         2f
-        // copies 8 bytes, destination 64-bits aligned
-        vld1.8      {d0}, [r1]!
-        vst1.8      {d0}, [r0, :64]!
+#if (PLDTHRESH < PLDOFFS)
+#error PLD threshold must be greater than or equal to the PLD offset
+#endif
 
-2:      /* make sure we have at least 64 bytes to copy */
-        subs        r2, r2, #64
-        blo         2f
+	.text
+	.fpu    neon
 
-1:      /* The main loop copies 64 bytes at a time */
-        vld1.8      {d0  - d3},   [r1]!
-        vld1.8      {d4  - d7},   [r1]!
-        pld         [r1, #(32*8)]
-        subs        r2, r2, #64
-        vst1.8      {d0  - d3},   [r0, :128]!
-        vst1.8      {d4  - d7},   [r0, :128]!
-        bhs         1b
+.L_memcpy_base:
+	cmp	r2, #4
+	blt	.L_neon_lt4
+	cmp	r2, #16
+	blt	.L_neon_lt16
+	cmp	r2, #32
+	blt	.L_neon_16
+	cmp	r2, #64
+	blt	.L_neon_copy_32_a
 
-2:      /* fix-up the remaining count and make sure we have >= 32 bytes left */
-        adds        r2, r2, #32
-        blo         4f
+	mov	r12, r2, lsr #6
+	cmp	r12, #PLDTHRESH
+	ble	.L_neon_copy_64_loop_nopld
 
-        /* Copy 32 bytes. These cache lines were already preloaded */
-        vld1.8      {d0 - d3},  [r1]!
-        sub         r2, r2, #32
-        vst1.8      {d0 - d3},  [r0, :128]!
+	push	{r9, r10}
+	.cfi_adjust_cfa_offset 8
+	.cfi_rel_offset r9, 0
+	.cfi_rel_offset r10, 4
 
-4:      /* less than 32 left */
-        add         r2, r2, #32
-        tst         r2, #0x10
-        beq         5f
-        // copies 16 bytes, 128-bits aligned
-        vld1.8      {d0, d1}, [r1]!
-        vst1.8      {d0, d1}, [r0, :128]!
+	cmp	r12, #BBTHRESH
+	ble	.L_neon_prime_pump
 
-5:      /* copy up to 15-bytes (count in r2) */
-        movs        ip, r2, lsl #29
-        bcc         1f
-        vld1.8      {d0}, [r1]!
-        vst1.8      {d0}, [r0]!
-1:      bge         2f
-        vld4.8      {d0[0], d1[0], d2[0], d3[0]}, [r1]!
-        vst4.8      {d0[0], d1[0], d2[0], d3[0]}, [r0]!
-2:      movs        ip, r2, lsl #31
-        itt         mi
-        ldrbmi      r3, [r1], #1
-        strbmi      r3, [r0], #1
-        itttt       cs
-        ldrbcs      ip, [r1], #1
-        ldrbcs      lr, [r1], #1
-        strbcs      ip, [r0], #1
-        strbcs      lr, [r0], #1
+	add	lr, r0, #0x400
+	add	r9, r1, #(PLDOFFS*PLDSIZE)
+	sub	lr, lr, r9
+	lsl	lr, lr, #21
+	lsr	lr, lr, #21
+	add	lr, lr, #(PLDOFFS*PLDSIZE)
+	cmp	r12, lr, lsr #6
+	ble	.L_neon_prime_pump
 
-        ldmfd       sp!, {r0, pc}
-END(MEMCPY_BASE)
+	itt	gt
+	movgt	r9, #(PLDOFFS)
+	rsbsgt	r9, r9, lr, lsr #6
+	ble	.L_neon_prime_pump
+
+	add	r10, r1, lr
+	bic	r10, #0x3F
+
+	sub	r12, r12, lr, lsr #6
+
+	cmp	r9, r12
+	itee	le
+	suble	r12, r12, r9
+	movgt	r9, r12
+	movgt	r12, #0
+
+	pld	[r1, #((PLDOFFS-1)*PLDSIZE)]
+.L_neon_copy_64_loop_outer_doublepld:
+	pld	[r1, #((PLDOFFS)*PLDSIZE)]
+	vld1.32	{q0, q1}, [r1]!
+	vld1.32	{q2, q3}, [r1]!
+	ldr	r3, [r10]
+	subs	r9, r9, #1
+	vst1.32	{q0, q1}, [r0]!
+	vst1.32	{q2, q3}, [r0]!
+	add	r10, #64
+	bne	.L_neon_copy_64_loop_outer_doublepld
+	cmp	r12, #0
+	beq	.L_neon_pop_before_nopld
+
+	cmp	r12, #(512*1024/64)
+	blt	.L_neon_copy_64_loop_outer
+
+.L_neon_copy_64_loop_ddr:
+	vld1.32	{q0, q1}, [r1]!
+	vld1.32	{q2, q3}, [r1]!
+	pld	[r10]
+	subs	r12, r12, #1
+	vst1.32	{q0, q1}, [r0]!
+	vst1.32	{q2, q3}, [r0]!
+	add	r10, #64
+	bne	.L_neon_copy_64_loop_ddr
+	b	.L_neon_pop_before_nopld
+
+.L_neon_prime_pump:
+	mov	lr, #(PLDOFFS*PLDSIZE)
+	add	r10, r1, #(PLDOFFS*PLDSIZE)
+	bic	r10, #0x3F
+	sub	r12, r12, #PLDOFFS
+	ldr	r3, [r10, #(-1*PLDSIZE)]
+
+.L_neon_copy_64_loop_outer:
+	vld1.32	{q0, q1}, [r1]!
+	vld1.32	{q2, q3}, [r1]!
+	ldr	r3, [r10]
+	subs	r12, r12, #1
+	vst1.32	{q0, q1}, [r0]!
+	vst1.32	{q2, q3}, [r0]!
+	add	r10, #64
+	bne	.L_neon_copy_64_loop_outer
+
+.L_neon_pop_before_nopld:
+	mov	r12, lr, lsr #6
+	pop	{r9, r10}
+	.cfi_adjust_cfa_offset -8
+	.cfi_restore r9
+	.cfi_restore r10
+
+.L_neon_copy_64_loop_nopld:
+	vld1.32	{q8, q9}, [r1]!
+	vld1.32	{q10, q11}, [r1]!
+	subs	r12, r12, #1
+	vst1.32	{q8, q9}, [r0]!
+	vst1.32	{q10, q11}, [r0]!
+	bne	.L_neon_copy_64_loop_nopld
+	ands	r2, r2, #0x3f
+	beq	.L_neon_exit
+
+.L_neon_copy_32_a:
+	movs	r3, r2, lsl #27
+	bcc	.L_neon_16
+	vld1.32	{q0,q1}, [r1]!
+	vst1.32	{q0,q1}, [r0]!
+
+.L_neon_16:
+	bpl	.L_neon_lt16
+	vld1.32	{q8}, [r1]!
+	vst1.32	{q8}, [r0]!
+	ands	r2, r2, #0x0f
+	beq	.L_neon_exit
+
+.L_neon_lt16:
+	movs	r3, r2, lsl #29
+	bcc	1f
+	vld1.8	{d0}, [r1]!
+	vst1.8	{d0}, [r0]!
+1:
+	bge	.L_neon_lt4
+	vld4.8	{d0[0], d1[0], d2[0], d3[0]}, [r1]!
+	vst4.8	{d0[0], d1[0], d2[0], d3[0]}, [r0]!
+
+.L_neon_lt4:
+	movs	r2, r2, lsl #31
+	itt	cs
+	ldrhcs	r3, [r1], #2
+	strhcs	r3, [r0], #2
+	itt	mi
+	ldrbmi	r3, [r1]
+	strbmi	r3, [r0]
+
+.L_neon_exit:
+	pop	{r0, pc}
diff --git a/libc/bionic/sysinfo.cpp b/libc/bionic/sysinfo.cpp
index a48bfea..1cb5c79 100644
--- a/libc/bionic/sysinfo.cpp
+++ b/libc/bionic/sysinfo.cpp
@@ -33,6 +33,7 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "private/get_cpu_count_from_string.h"
 #include "private/ScopedReaddir.h"
 
 static bool __matches_cpuN(const char* s) {
@@ -61,26 +62,18 @@
 }
 
 int get_nprocs() {
-  FILE* fp = fopen("/proc/stat", "re");
-  if (fp == NULL) {
-    return 1;
-  }
-
-  int result = 0;
-  char buf[256];
-  while (fgets(buf, sizeof(buf), fp) != NULL) {
-    // Extract just the first word from the line.
-    // 'cpu0 7976751 1364388 3116842 469770388 8629405 0 49047 0 0 0'
-    char* p = strchr(buf, ' ');
-    if (p != NULL) {
-      *p = 0;
+  int cpu_count = 1;
+  FILE* fp = fopen("/sys/devices/system/cpu/online", "re");
+  if (fp != nullptr) {
+    char* line = nullptr;
+    size_t len = 0;
+    if (getline(&line, &len, fp) != -1) {
+      cpu_count = GetCpuCountFromString(line);
+      free(line);
     }
-    if (__matches_cpuN(buf)) {
-      ++result;
-    }
+    fclose(fp);
   }
-  fclose(fp);
-  return result;
+  return cpu_count;
 }
 
 static int __get_meminfo_page_count(const char* pattern) {
diff --git a/libc/private/get_cpu_count_from_string.h b/libc/private/get_cpu_count_from_string.h
new file mode 100644
index 0000000..a0cb95d
--- /dev/null
+++ b/libc/private/get_cpu_count_from_string.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <ctype.h>
+#include <stdlib.h>
+
+// Parse a string like: 0, 2-4, 6.
+static int GetCpuCountFromString(const char* s) {
+  int cpu_count = 0;
+  int last_cpu = -1;
+  while (*s != '\0') {
+    if (isdigit(*s)) {
+      int cpu = static_cast<int>(strtol(s, const_cast<char**>(&s), 10));
+      if (last_cpu != -1) {
+        cpu_count += cpu - last_cpu;
+      } else {
+        cpu_count++;
+      }
+      last_cpu = cpu;
+    } else {
+      if (*s == ',') {
+        last_cpu = -1;
+      }
+      s++;
+    }
+  }
+  return cpu_count;
+}
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 7421b1d..80ff583 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -41,6 +41,7 @@
 
 #include <new>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 // Private C library headers.
@@ -1121,7 +1122,50 @@
   return nullptr;
 }
 
-static int open_library_in_zipfile(const char* const path,
+class ZipArchiveCache {
+ public:
+  ZipArchiveCache() {}
+  ~ZipArchiveCache();
+
+  bool get_or_open(const char* zip_path, ZipArchiveHandle* handle);
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ZipArchiveCache);
+
+  std::unordered_map<std::string, ZipArchiveHandle> cache_;
+};
+
+bool ZipArchiveCache::get_or_open(const char* zip_path, ZipArchiveHandle* handle) {
+  std::string key(zip_path);
+
+  auto it = cache_.find(key);
+  if (it != cache_.end()) {
+    *handle = it->second;
+    return true;
+  }
+
+  int fd = TEMP_FAILURE_RETRY(open(zip_path, O_RDONLY | O_CLOEXEC));
+  if (fd == -1) {
+    return false;
+  }
+
+  if (OpenArchiveFd(fd, "", handle) != 0) {
+    // invalid zip-file (?)
+    close(fd);
+    return false;
+  }
+
+  cache_[key] = *handle;
+  return true;
+}
+
+ZipArchiveCache::~ZipArchiveCache() {
+  for (auto it : cache_) {
+    CloseArchive(it.second);
+  }
+}
+
+static int open_library_in_zipfile(ZipArchiveCache* zip_archive_cache,
+                                   const char* const path,
                                    off64_t* file_offset) {
   TRACE("Trying zip file open from path '%s'", path);
 
@@ -1150,16 +1194,12 @@
   }
 
   ZipArchiveHandle handle;
-  if (OpenArchiveFd(fd, "", &handle, false) != 0) {
+  if (!zip_archive_cache->get_or_open(zip_path, &handle)) {
     // invalid zip-file (?)
     close(fd);
     return -1;
   }
 
-  auto archive_guard = make_scope_guard([&]() {
-    CloseArchive(handle);
-  });
-
   ZipEntry entry;
 
   if (FindEntry(handle, ZipString(file_path), &entry) != 0) {
@@ -1205,7 +1245,8 @@
   return -1;
 }
 
-static int open_library_on_paths(const char* name, off64_t* file_offset,
+static int open_library_on_paths(ZipArchiveCache* zip_archive_cache,
+                                 const char* name, off64_t* file_offset,
                                  const std::vector<std::string>& paths) {
   for (const auto& path_str : paths) {
     char buf[512];
@@ -1216,7 +1257,7 @@
 
     int fd = -1;
     if (strstr(buf, kZipFileSeparator) != nullptr) {
-      fd = open_library_in_zipfile(buf, file_offset);
+      fd = open_library_in_zipfile(zip_archive_cache, buf, file_offset);
     }
 
     if (fd == -1) {
@@ -1234,13 +1275,15 @@
   return -1;
 }
 
-static int open_library(const char* name, soinfo *needed_by, off64_t* file_offset) {
+static int open_library(ZipArchiveCache* zip_archive_cache,
+                        const char* name, soinfo *needed_by,
+                        off64_t* file_offset) {
   TRACE("[ opening %s ]", name);
 
   // If the name contains a slash, we should attempt to open it directly and not search the paths.
   if (strchr(name, '/') != nullptr) {
     if (strstr(name, kZipFileSeparator) != nullptr) {
-      int fd = open_library_in_zipfile(name, file_offset);
+      int fd = open_library_in_zipfile(zip_archive_cache, name, file_offset);
       if (fd != -1) {
         return fd;
       }
@@ -1254,13 +1297,15 @@
   }
 
   // Otherwise we try LD_LIBRARY_PATH first, and fall back to the built-in well known paths.
-  int fd = open_library_on_paths(name, file_offset, g_ld_library_paths);
+  int fd = open_library_on_paths(zip_archive_cache, name, file_offset, g_ld_library_paths);
   if (fd == -1 && needed_by) {
-    fd = open_library_on_paths(name, file_offset, needed_by->get_dt_runpath());
+    fd = open_library_on_paths(zip_archive_cache, name, file_offset, needed_by->get_dt_runpath());
   }
+
   if (fd == -1) {
     fd = open_library_on_default_path(name, file_offset);
   }
+
   return fd;
 }
 
@@ -1367,7 +1412,8 @@
   return si;
 }
 
-static soinfo* load_library(LoadTaskList& load_tasks, const char* name,
+static soinfo* load_library(ZipArchiveCache* zip_archive_cache,
+                            LoadTaskList& load_tasks, const char* name,
                             soinfo* needed_by, int rtld_flags,
                             const android_dlextinfo* extinfo) {
   if (extinfo != nullptr && (extinfo->flags & ANDROID_DLEXT_USE_LIBRARY_FD) != 0) {
@@ -1380,7 +1426,7 @@
 
   // Open the file.
   off64_t file_offset;
-  int fd = open_library(name, needed_by, &file_offset);
+  int fd = open_library(zip_archive_cache, name, needed_by, &file_offset);
   if (fd == -1) {
     DL_ERR("library \"%s\" not found", name);
     return nullptr;
@@ -1427,7 +1473,8 @@
   return false;
 }
 
-static soinfo* find_library_internal(LoadTaskList& load_tasks, const char* name,
+static soinfo* find_library_internal(ZipArchiveCache* zip_archive_cache,
+                                     LoadTaskList& load_tasks, const char* name,
                                      soinfo* needed_by, int rtld_flags,
                                      const android_dlextinfo* extinfo) {
   soinfo* candidate;
@@ -1441,7 +1488,7 @@
   TRACE("[ '%s' find_loaded_library_by_soname returned false (*candidate=%s@%p). Trying harder...]",
       name, candidate == nullptr ? "n/a" : candidate->get_realpath(), candidate);
 
-  soinfo* si = load_library(load_tasks, name, needed_by, rtld_flags, extinfo);
+  soinfo* si = load_library(zip_archive_cache, load_tasks, name, needed_by, rtld_flags, extinfo);
 
   // In case we were unable to load the library but there
   // is a candidate loaded under the same soname but different
@@ -1521,15 +1568,18 @@
     }
   });
 
+  ZipArchiveCache zip_archive_cache;
+
   // Step 1: load and pre-link all DT_NEEDED libraries in breadth first order.
   for (LoadTask::unique_ptr task(load_tasks.pop_front());
       task.get() != nullptr; task.reset(load_tasks.pop_front())) {
     soinfo* needed_by = task->get_needed_by();
     bool is_dt_needed = needed_by != nullptr && (needed_by != start_with || add_as_children);
 
-    soinfo* si = find_library_internal(load_tasks, task->get_name(), needed_by,
-                                       rtld_flags,
+    soinfo* si = find_library_internal(&zip_archive_cache, load_tasks,
+                                       task->get_name(), needed_by, rtld_flags,
                                        is_dt_needed ? nullptr : extinfo);
+
     if (si == nullptr) {
       return false;
     }
diff --git a/tests/dlext_test.cpp b/tests/dlext_test.cpp
index 44b899e..9d8b71d 100644
--- a/tests/dlext_test.cpp
+++ b/tests/dlext_test.cpp
@@ -52,15 +52,15 @@
 #define LIBSIZE 1024*1024 // how much address space to reserve for it
 
 #if defined(__LP64__)
-#define LIBPATH_PREFIX "/nativetest64/libdlext_test_fd/"
+#define LIBPATH_PREFIX "/nativetest64/"
 #else
-#define LIBPATH_PREFIX "/nativetest/libdlext_test_fd/"
+#define LIBPATH_PREFIX "/nativetest/"
 #endif
 
-#define LIBPATH LIBPATH_PREFIX "libdlext_test_fd.so"
-#define LIBZIPPATH LIBPATH_PREFIX "libdlext_test_fd_zipaligned.zip"
+#define LIBPATH LIBPATH_PREFIX "libdlext_test_fd/libdlext_test_fd.so"
+#define LIBZIPPATH LIBPATH_PREFIX "libdlext_test_zip/libdlext_test_zip_zipaligned.zip"
 
-#define LIBZIP_OFFSET 2*PAGE_SIZE
+#define LIBZIP_OFFSET PAGE_SIZE
 
 class DlExtTest : public ::testing::Test {
 protected:
@@ -131,9 +131,9 @@
   handle_ = android_dlopen_ext(lib_path.c_str(), RTLD_NOW, &extinfo);
   ASSERT_DL_NOTNULL(handle_);
 
-  fn f = reinterpret_cast<fn>(dlsym(handle_, "getRandomNumber"));
-  ASSERT_DL_NOTNULL(f);
-  EXPECT_EQ(4, f());
+  uint32_t* taxicab_number = reinterpret_cast<uint32_t*>(dlsym(handle_, "dlopen_testlib_taxicab_number"));
+  ASSERT_DL_NOTNULL(taxicab_number);
+  EXPECT_EQ(1729U, *taxicab_number);
 }
 
 TEST_F(DlExtTest, ExtInfoUseFdWithInvalidOffset) {
@@ -163,7 +163,7 @@
   ASSERT_TRUE(handle_ == nullptr);
   ASSERT_SUBSTR("dlopen failed: file offset for the library \"libname_placeholder\" is negative", dlerror());
 
-  extinfo.library_fd_offset = PAGE_SIZE;
+  extinfo.library_fd_offset = 0;
   handle_ = android_dlopen_ext("libname_ignored", RTLD_NOW, &extinfo);
   ASSERT_TRUE(handle_ == nullptr);
   ASSERT_EQ("dlopen failed: \"" + lib_realpath + "\" has bad ELF magic", dlerror());
@@ -218,13 +218,12 @@
 TEST(dlfcn, dlopen_from_zip_absolute_path) {
   const std::string lib_path = std::string(getenv("ANDROID_DATA")) + LIBZIPPATH;
 
-  void* handle = dlopen((lib_path + "!/libdir/libdlext_test_fd.so").c_str(), RTLD_NOW);
+  void* handle = dlopen((lib_path + "!/libdir/libatest_simple_zip.so").c_str(), RTLD_NOW);
   ASSERT_TRUE(handle != nullptr) << dlerror();
 
-  int (*fn)(void);
-  fn = reinterpret_cast<int (*)(void)>(dlsym(handle, "getRandomNumber"));
-  ASSERT_TRUE(fn != nullptr);
-  EXPECT_EQ(4, fn());
+  uint32_t* taxicab_number = reinterpret_cast<uint32_t*>(dlsym(handle, "dlopen_testlib_taxicab_number"));
+  ASSERT_DL_NOTNULL(taxicab_number);
+  EXPECT_EQ(1729U, *taxicab_number);
 
   dlclose(handle);
 }
@@ -238,12 +237,12 @@
 
   ASSERT_TRUE(android_update_LD_LIBRARY_PATH != nullptr) << dlerror();
 
-  void* handle = dlopen("libdlext_test_fd.so", RTLD_NOW);
+  void* handle = dlopen("libdlext_test_zip.so", RTLD_NOW);
   ASSERT_TRUE(handle == nullptr);
 
   android_update_LD_LIBRARY_PATH(lib_path.c_str());
 
-  handle = dlopen("libdlext_test_fd.so", RTLD_NOW);
+  handle = dlopen("libdlext_test_zip.so", RTLD_NOW);
   ASSERT_TRUE(handle != nullptr) << dlerror();
 
   int (*fn)(void);
@@ -251,6 +250,10 @@
   ASSERT_TRUE(fn != nullptr);
   EXPECT_EQ(4, fn());
 
+  uint32_t* taxicab_number = reinterpret_cast<uint32_t*>(dlsym(handle, "dlopen_testlib_taxicab_number"));
+  ASSERT_DL_NOTNULL(taxicab_number);
+  EXPECT_EQ(1729U, *taxicab_number);
+
   dlclose(handle);
 }
 
diff --git a/tests/libs/Android.build.dlext_testzip.mk b/tests/libs/Android.build.dlext_testzip.mk
index 1e89411..93df213 100644
--- a/tests/libs/Android.build.dlext_testzip.mk
+++ b/tests/libs/Android.build.dlext_testzip.mk
@@ -21,21 +21,21 @@
 include $(CLEAR_VARS)
 
 LOCAL_MODULE_CLASS := SHARED_LIBRARIES
-LOCAL_MODULE := libdlext_test_fd_zipaligned
+LOCAL_MODULE := libdlext_test_zip_zipaligned
 LOCAL_MODULE_SUFFIX := .zip
 LOCAL_MODULE_TAGS := tests
-LOCAL_MODULE_PATH := $($(bionic_2nd_arch_prefix)TARGET_OUT_DATA_NATIVE_TESTS)/libdlext_test_fd
+LOCAL_MODULE_PATH := $($(bionic_2nd_arch_prefix)TARGET_OUT_DATA_NATIVE_TESTS)/libdlext_test_zip
 LOCAL_2ND_ARCH_VAR_PREFIX := $(bionic_2nd_arch_prefix)
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
 my_shared_libs := \
-  $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libdlext_test_fd.so
+  $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libdlext_test_zip.so \
+  $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libatest_simple_zip.so
 
-$(LOCAL_BUILT_MODULE): PRIVATE_ALIGNMENT := 4096 # PAGE_SIZE
 $(LOCAL_BUILT_MODULE) : $(my_shared_libs) | $(ZIPALIGN)
 	@echo "Zipalign $(PRIVATE_ALIGNMENT): $@"
 	$(hide) rm -rf $(dir $@) && mkdir -p $(dir $@)/libdir
 	$(hide) cp $^ $(dir $@)/libdir
 	$(hide) (cd $(dir $@) && touch empty_file.txt && zip -qrD0 $(notdir $@).unaligned empty_file.txt libdir/*.so)
-	$(hide) $(ZIPALIGN) $(PRIVATE_ALIGNMENT) $@.unaligned $@
+	$(hide) $(ZIPALIGN) -p 4 $@.unaligned $@
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index b13400e..3391d79 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -126,6 +126,32 @@
 build_target := SHARED_LIBRARY
 include $(TEST_PATH)/Android.build.mk
 
+
+# -----------------------------------------------------------------------------
+# Libraries used by dlext tests for open from a zip-file
+# -----------------------------------------------------------------------------
+libdlext_test_zip_src_files := \
+    dlext_test_library.cpp \
+
+libdlext_test_zip_shared_libraries := libatest_simple_zip
+
+libdlext_test_zip_install_to_out_data := true
+module := libdlext_test_zip
+module_tag := optional
+build_type := target
+build_target := SHARED_LIBRARY
+include $(TEST_PATH)/Android.build.mk
+
+libatest_simple_zip_src_files := \
+    dlopen_testlib_simple.cpp
+
+libatest_simple_zip_install_to_out_data := true
+module := libatest_simple_zip
+module_tag := optional
+build_type := target
+build_target := SHARED_LIBRARY
+include $(TEST_PATH)/Android.build.mk
+
 # ----------------------------------------------------------------------------
 # Library with soname which does not match filename
 # ----------------------------------------------------------------------------
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 8e1f412..500377c 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -30,6 +30,11 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include <base/file.h>
+#include <base/strings.h>
+
+#include "private/get_cpu_count_from_string.h"
+
 static void* get_brk() {
   return sbrk(0);
 }
@@ -819,6 +824,29 @@
 #endif // defined(__BIONIC__)
 }
 
+TEST(unistd, get_cpu_count_from_string) {
+  ASSERT_EQ(0, GetCpuCountFromString(" "));
+  ASSERT_EQ(1, GetCpuCountFromString("0"));
+  ASSERT_EQ(40, GetCpuCountFromString("0-39"));
+  ASSERT_EQ(4, GetCpuCountFromString("0, 1-2, 4\n"));
+}
+
+TEST(unistd, sysconf_SC_NPROCESSORS_ONLN) {
+  std::string s;
+  ASSERT_TRUE(android::base::ReadFileToString("/sys/devices/system/cpu/online", &s));
+  std::vector<std::string> strs = android::base::Split(s, ",");
+  long online_cpus = 0;
+  for (auto& s : strs) {
+    std::vector<std::string> numbers = android::base::Split(s, "-");
+    if (numbers.size() == 1u) {
+      online_cpus++;
+    } else {
+      online_cpus += atoi(numbers[1].c_str()) - atoi(numbers[0].c_str()) + 1;
+    }
+  }
+  ASSERT_EQ(online_cpus, sysconf(_SC_NPROCESSORS_ONLN));
+}
+
 TEST(unistd, dup2_same) {
   // POSIX says of dup2:
   // If fildes2 is already a valid open file descriptor ...